Interview: Finisar’s CEO reflects on a notable year
Michael Hurlston has had an eventful 2018.
The year started with him replacing Finisar’s veteran CEO, Jerry Rawls, and it is now ending with Finisar being acquired by the firm II-VI for $3.2 billion.
Finisar is Hurlston’s first experience in the optical component industry, having spent his career in semiconductors. One year in and he already has strong views about the industry and its direction.
Michael Hurlston
“We have seen in the semiconductor industry a period of massive consolidation in the last three to four years,” says Hurlston, in his first interview sinced the deal was announced. “I think it is not that different in optics: scales matters.”
Hurlston says that, right from the start, he recognised the need to drive industry consolidation. “We had started thinking about that fairly deeply at the time the Lumentum-Oclaro acquisition was announced and that gave us more impetus to look at this,” says Hurlston. The result was revealed in November with the announced acquisition of Finisar by II-VI.
“Finisar considered so many deals in the past but could not converge on a solution,” says Vladimir Kozlov, CEO and founder of market research firm, LightCounting. "It needed a new CEO to bring a different perspective. The new II-VI will look more like many diversified semiconductor vendors, addressing multiple markets: automotive, industrial and communications."
“We really have two complementary companies for the most part,” says Hurlston, who highlights VCSELs and reconfigurable optical add-drop multiplexers (ROADMs) as the only product segments where there is overlap. Merging II-VI and Finisar with disparate portfolios further benefits scale, he says.
Chip background
Hurlston’s semiconductor experience was gained at Broadcom and involved Wi-Fi devices. The key lessons he learned there is the importance of offering differentiated products to customers and the need to expand into new application areas.
“Wi-Fi is a standard, a technology, that has rules as you have to interoperate between different chipsets and different producers,” says Hurlston. “But we did find ways to differentiate under a standards umbrella.”
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“It turns out co-packaging is a great top-line opportunity for optics companies because eventually we will be tasked with pulling together that sub-system”
What he has found, to his surprise, is that it is harder to differentiate in the optical components industry. “What we are trying to do is find spots where we can offer differentiation,” says Hurlston.
Optical components usage needs to also expand into new segments, he says, just as Wi-Fi evolved from a PC-centric technology to home networking and ultimately mobile handsets.
Hurlston cites as an example in the optical components industry how VCSELs are now being used for 3D sensing in handsets. There are also emerging opportunities in automotive and the data centre.
For the automative market, applications include in-cabin sensing to assist drivers and LIDAR (laser detection and ranging) to help vehicles build up an image of their surroundings in real-time. “LIDAR is further out but it is a significant opportunity,” says Hurlston.
For data centres, a key opportunity silicon co-packaging: bringing optics closer to switch silicon.
Currently, switch platform use pluggable optical modules on the faceplate to send and receive data. But with switch silicon capacity doubling every two years, the speed and density of the input-output means optics will have to get closer to the switch silicon.
On-board optics - as promoted by the Consortium for On-Board Optics (COBO) - is one option. Another is co-packaged optics, where the optics and silicon are placed in the same package.
“It turns out co-packaging is a great top-line opportunity for optics companies because eventually we will be tasked with pulling together that sub-system,” says Hurlston. “The integration of the switch chip and optics is something that will be technically difficult and necessitate differentiation.”
Challenges
As well as the issue of acquisitions, another area Hurlston has tackled in his short tenure is Finisar’s manufacturing model and how it can be improved.
“Finisar is a technology company at heart but the life-blood of the company is manufacturing,” he says.
Manufacturing is also one area where there is a notable difference between chips and optics. “There are manufacturing complexities with semiconductors and semiconductor process but optics takes it to a whole different level,” he says.
This is due to the manufacturing complexity of optical transceiver which Finisar’s CEO likens to manufacturing a mobile phone. There are chips that need a printed circuit board onto which are also added optical subassemblies housing such components as lasers and photo-detectors.
“Part of it [the complexity] is the human labour - the human touch - that is involved in the manufacturing and assembling of these transceivers ” he says. Finisar says its laser fab employs several hundred people whereas its optical transceiver factories employ thousands: 5,000 staff in Malaysia and some 5,500 in China.
“Our manufacturing model has been where I’ve spent a lot of time,” says Hurston. Some efficiencies have been gained but not nearly as much as he initially hoped.
Consolidation
One of the issues that has hindered greater industry consolidation has been the need for synergy between companies. A semiconductor company will only acquire or merge with another semiconductor company, and the same with a laser company looking for another laser player, he says. “What I admire about II-VI is that they are pretty bold,” says Hurlston. “What II-VI did is go after something that is not overlapping.”
He believes the creation of such broad-based suppliers is something the optics industry will have to do more of: “The transceiver guys are going to have to go after different areas of the value chain.”
In most mature industries, three large diversified companies typically dominate the marketplace. Given Lumentum’s acquisition of Oclaro has just closed and II-VI’s acquisition of Finisar is due to be completed in mid-2019, will there be another large deal?
“This is a big industry and the opportunity today and going forward is big,” says Hurlston. But there are so many players in different parts of the supply chain such that he is unsure whether these niche companies will survive in the long run.
“Whether there will be three, four or five large players, I don’t know,” he says. “But we are definitely going to see fewer; this [II-VI - Finisar deal] isn't the last transaction that drives industry consolidation.”
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“Whether there will be three, four or five large players, I don’t know but we are definitely going to see fewer”
How will Finisar make optical transceivers in such a competitive marketplace, that includes an increasing number of Chinese entrants, while delivering gross margins that meet Wall Street expectations?
Finisar does have certain advantages, he says, such as making its own lasers. “We also make our own semiconductors, a lot of the semiconductor solutions the Chinese guys have are sourced,” he says. “That gives us an inherent advantage.”
Having its own manufacturing facilities in the Far East means that Chinese players have no inherent manufacturing advantage there. However, he admits that the gross margin expected of Finisar is higher that its Chinese competitors.
This is why Finisar’s CEO stresses the need to pursue pockets of differentiation and why the company has to be first to market in important productareas that all players will target. “We historically have not been first to market,” he says. “We have made adjustments in the last year in our time-to-market and our ability to get to big products transitions that will be hyper-competitive first.”
Hurston expresses some satisfaction in the improved revenues and gross margins as reported in Finisar’s last two quarters’ results, albeit these quarters coming after what he calls ‘a low base’.
“We have also made significant progress in 3D sensing that has been a big challenge for us,” he says.
What next?
Hurlston says he hopes to have a role in the new company once the deal closes.
“But If I don’t, I’ve really enjoyed working with the [Finisar] team and in this space,” he says. “It’s been a bit of a learning curve but I’ve learnt a couple of tricks. Hopefully there will be another opportunity to apply some of that learning to a job elsewhere.”
Finisar demonstrates its first silicon photonics transceiver
- Finisar unveiled its first silicon photonics-based product, a 400-gigabit QSFP-DD DR4 module, at the recent ECOC event.
- The company also showed transceiver technology that simplifies the setting up of dense wavelength-division multiplexing (DWDM) links.
- Two 200-gigabit QSFP56 client-side modules and an extended reach 30km 400-gigabit eLR8 were also demonstrated by Finisar.
- A 64-gigabaud integrated tunable transmitter and receiver assembly (ITTRA) was used to send a 400-gigabit coherent wavelength.
Finisar is bringing to market its first silicon photonics-based optical module.
Christian UrricarietThe 400GBASE-DR4 is an IEEE 500m-reach 400-gigabit parallel fibre standard based on four fibres, each carrying a 100-gigabit 4-level pulse amplitude modulation (PAM-4) signal. Finisar’s DR4 is integrated into a QSFP-DD module.
“The DR4 is the 400-gigabit interface that most of the hyperscale cloud players are interested in first,” says Christian Urricariet, senior director of global marketing at Finisar.
The company demonstrated the module at the recent European Conference on Optical Communication (ECOC), held in Rome.
Silicon photonics-based DR4
The DR4 is an integrated design, says Finisar, comprising modulators and photo-detectors as well as modulator drivers and the trans-impedance amplifiers (TIAs).
Finisar chose silicon photonics for the DR4 after undertaking an extensive technology study. Silicon photonics emerged as ‘a clear winner’ in terms of cost and performance for photonic designs made up of similar functions in parallel, such as the four-channel DR4. Silicon photonics manufacturing is also scalable, making it ideal for high-volume designs.
The DR4 is the 400-gigabit interface that most of the hyperscale cloud players are interested in first
The DR4 can also be used in a breakout mode to interface to four 100GBASE-DR modules. Also referred to as the DR1, the 100GBASE-DR fits within an SFP-DD or a QSFP28 module.
The DR4-DR1 combination can link four servers, each using a 100-gigabit link, to a 400-gigabit port on a top-of-rack or mid-row switch. The top-of-rack 400-gigabit DR4 can also connect to a leaf switch with multiple 100-gigabit ports. “The DR4 can be used ‘top-of-rack down’ [to servers] or ‘top-of-rack up’ [to leaf switches],” says Urricariet. “This is similar to what people are doing with the [100-gigabit parallel fibre] PSM4.”
400-gigabit eLR8
Finisar also showcased an extended reach version of the IEEE 400GBASE-LR8 standard.
Dubbed the eLR8, the QSFP-DD module is a technology demonstrator not a product that extends the reach of the LR8 from 10km to 30km.
Finisar already has an LR8 product in a CFP8 pluggable module and is moving the design to the smaller QSFP-DD. The LR8 is an eight-wavelength duplex interface where each wavelength carries a 50-gigabit PAM-4 signal.
“The 400GBASE-LR8 is a low-risk approach to achieving a 400-gigabit duplex single-mode link in the short term,” says Urricariet. “You don’t have to wait for 100-gigabit PAM-4 [ICs] to be manufactured in high volume.”
Urricariet says the IEEE is considering developing an extended LR8 standard with a 40km reach but such distances could also be addressed using inexpensive coherent technology.
Finisar’s design achieves the extended range using the same components as its LR8 module - directly modulated DFB lasers and PIN photodetectors. “There is plenty of margin with that [LR8 design],” says Urricariet. This suggests Finisar picked the best performing DFBs and PINs for the eLR8 design.
The QSFP-DD 10km LR8 design is sampling now, with general availability from the first half of 2019.
Flextune
Configuring DWDM links can be likened to two groups of people separated in a wood at night. Each individual has a flashlight and is tasked with finding a counterpart from the second group, a process repeated until everyone is paired.
Setting up DWDM links is comparable to telling each individual the exact path to take to find their counterpart. The Flextune technology that Finisar has developed can be viewed as giving each individual the confidence to stride out - sweeping their flashlights as they go - till they find a counterpart.
Currently, setting up a DWDM link requires coordination between a field engineer and network operations staff. Each tunable transceiver that is plugged into a port is told which wavelength to tune to. The system itself may tell the transceiver the wavelength to use or a field engineer programs each transceiver before it is plugged into the platform.
Equally, the transceiver output fibre must be connected to the right optical multiplexer and demultiplexer (mux-demux) port, as do the transceivers at the link’s other end.
The result is a time-consuming process that is prone to human error.
With Flextune, the tunable transceivers are plugged into the equipment’s ports and connected to the mux-demux’s ports. “It does not matter which port,” says Urricariet. “The transceivers search for each other and self-configure to the right wavelength.”
Each Flextune-enabled transceiver operates independently of the transceiver at the other end; there is no master-slave arrangement, says Urricariet, although a master-slave arrangement can be used if requested.
The mux-demux must also be a blocking architecture for Flextune to work. “If the mux-demux does not block the other wavelengths on each port, then you have a mess,” says Urricariet. With such a mux-demux, the channels scanned are blocked until the transceiver’s output is passed to the right channel. Once the link is established, the two transceivers set permanently to that wavelength.
“It [the process] happens at both ends simultaneously and on all the ports,” says Urricariet. “The basic technique can self-tune up to 96 [DWDM] channels in around five minutes.”
Being able to tune independently of the host equipment means that the Flextune-enabled transceivers can also be sold directly to operators and plugged into any of their equipment.
Urricariet says Flextune promises welcome operational savings given DWDM’s increasing adoption in the access network with developments such as 5G fronthaul.
The basic technique can self-tune up to 96 [DWDM] channels in around five minutes
Flextune will also be used for metro and data centre interconnect applications, as well as connecting Remote PHY nodes being deployed in cable networks. “The Remote PHY is also a big focus for this type of feature,” says Urricariet.
Finisar demonstrated Flextune with its 10-gigabit tunable SFP+ modules that are now sampling. Flextune will also be adopted for its 25-gigabit SFP+ that will sample ‘very soon’, followed by coherent modules.
“We do have a CFP2-ACO module in production and other coherent products on our roadmap,” says Urricariet. “We will be looking to implement Flextune technology in these products as well.”
Google has started deployments of 2x200GbE
200 Gigabit Ethernet: a growing interim solution
Finisar also demonstrated two 200-gigabit modules. The QSFP56 implements the 2km FR4 specification. The 200-gigabit FR4 uses four coarse WDM (CWDM) wavelengths, each carrying a 50-gigabit PAM-4 signal.
Finisar has previously said it will develop 200-gigabit modules for the large-scale data centres interested in the technology as an interim solution before 400-gigabit modules ramp. Such an intermediate market for “one hyperscaler and maybe two” is sufficient to justify making 200-gigabit modules, says Urricariet.
Market research firm LightCounting has increased its forecast for 200 Gigabit Ethernet (GbE) modules due to interest from Facebook.
A presentation by Facebook at ECOC suggested that 400 GbE is far from being ready, says Vladimir Kozlov, CEO of LightCounting. “It looks like 200GbE is being considered now, but Facebook may change its mind again,” says Kozlov. “In the meantime, Google has started deployments of 2x200GbE [in an OSFP module] as planned.”
As with the 400-gigabit eLR8, Finisar also demonstrated an extended reach version of the 200-gigabit FR4 to achieve a 10km reach. “This is not to be confused with the 10km 200-gigabit LR4 that is a LAN-WDM grid based design,” says Urricariet. “The extended FR4 uses a CWDM grid.”
ITTRA
At OFC 2018 in March, Finisar unveiled its 32-gigabaud (Gbaud) integrated tunable transmitter and receiver assembly (ITTRA) that combines the optics and electronics required for an analogue coherent optics interface.
The ITTRA comprises a tunable laser, an optical amplifier, modulators, modulator drivers, coherent mixers, a photo-detector array and the accompanying TIAs. All the components of the 32Gbaud ITTRA are integrated within a gold box that is 70 percent smaller than the size of a CFP2 module. The integrated assembly also has a power consumption below 7.5W.
At ECOC, the company demonstrated its second ITTRA design operating at 64Gbaud to transmit a 400-gigabit wavelength using 16-ary quadrature amplitude modulation (16-QAM). Finisar would not detail the power consumption of the 64Gbaud ITTRA.
“The doubling of the speed to 64Gbaud will enable 400-gigabit DCO modules as well as 400ZR,” says Urricariet. Digital coherent optics (DCO) refers to coherent modules that integrate the optics and the coherent digital signal processor (DSP).
Samples and production of the 64Gbaud ITTRA are due in 2019.
Optical module trends: A conversation with Finisar
Finisar demonstrated recently a raft of new products that address emerging optical module developments. These include:
- A compact coherent integrated tunable transmitter and receiver assembly
- 400GBASE-FR8 and -LR8 QSFP-DD pluggable modules and a QSFP-DD active optical cable
- A QSFP28 100-gigabit serial FR interface
- 50-gigabit SFP56 SR and LR modules
Rafik Ward, Finisar’s general manager of optical interconnects, explains the technologies and their uses.
Compact coherent
Finisar is sampling a compact integrated assembly that supports 100-gigabit and 200-gigabit coherent transmission.
The integrated tunable transmitter and receiver assembly (ITTRA), to give it its full title, includes the optics and electronics needed for an analogue coherent optics interface.
The 32-gigabaud ITTRA includes a tunable laser, optical amplifier, modulators, modulator drivers, coherent mixers, a photo-detector array and the accompanying trans-impedance amplifiers, all within a gold box. “An entire analogue coherent module in a footprint that is 70 percent smaller than the size of a CFP2 module,” says Ward. The ITTRA's power consumption is below 7.5W.
Rafik WardFinisar says the ITTRA is smaller than the equivalent integrated coherent transmitter-receiver optical sub-assembly (IC-TROSA) design being developed by the Optical Internetworking Forum (OIF).
“We potentially could take this device and enable it to work in that [IC-TROSA] footprint,” says Ward.
Using the ITTRA enables higher-density coherent line cards and frees up space within an optical module for the coherent digital signal processor (DSP) for a CFP2 Digital Coherent Optics (CFP2-DCO) design.
Ward says the CFP2 is a candidate for a 400-gigabit coherent pluggable module along with the QSFP-DD and OSFP form factors. “All have their pros and cons based on such fundamental things as the size of the form factor and power dissipation,” says Ward.
But given coherent DSPs implemented in 7nm CMOS required for 400 gigabit are not yet available, the 100 and 200-gigabit CFP2 remains the module of choice for coherent pluggable interfaces.
The demonstration of the ITTRA implementing a 200-gigabit link using 16-QAM at OFC 2018. Source: Finisar
400 gigabits
Finisar also demonstrated its first 400-gigabit QSFP-DD pluggable module products based on the IEEE standards: the 2km 400GBASE-FR8 and the 10km 400GBASE-LR8. The company also unveiled a QSFP-DD active optical cable to link equipment up to 70m apart.
The two QSFP-DD pluggable modules use eight 50-gigabit PAM-4 electrical signal inputs that are modulated onto eight lasers whose outputs are multiplexed and sent over a single fibre. Finisar chose to implement the IEEE standards as its first QSFP-DD products as they are low-power and lower risk 400-gigabit solutions.
The alternative 2km 400-gigabit design, developed by the 100 Lambda MSA, is the 400G-FR4 that uses four 100-gigabit optical lanes. “This has some risk elements to it such as the [PAM-4] DSP and making 100-gigabit serial lambdas work,” says Ward. “We think the -LR8 and -FR8 are complementary and could enable a fast time-to-market for people looking at these kinds of interfaces.”
The QSFP-DD active optical cable may have a reach of 70m but typical connections are 20m. Finisar uses its VCSEL technology to implement the 400-gigabit interface. At the OFC show in March, Finisar demonstrated the cable working with a Cisco high-density port count 1 rack-unit switch.
I sometimes get asked by customers what is the best way to get to higher-density 100 gigabit. I point to the 400-gigabit DR4.
QSFP28 FR
Finisar also showed it 2km QSFP28 optical module with a single wavelength 100-gigabit PAM-4 output. The QSFP28 FR takes four 25 gigabit-per-second electrical interfaces and passes them through a gearbox chip to form a 50-gigabaud PAM-4 signal that is used to modulate the laser.
The QSFP28 FR is expected to eventually replace the CWDM4 that uses four 25-gigabit wavelengths multiplexed onto a single fibre. “The end-game is to get a 100-gigabit serial module,” says Ward. “This module represents the first generation of that.”
Finisar is also planning a 500m QSFP28 DR. The QSFP28 DR and FR will work with the 500m IEEE 400GBASE-DR4 that has four outputs, each a fibre carrying a 100-gigabit PAM-4 signal, with the -DR4 outputs interfacing with up to four FR or DR modules.
“I sometimes get asked by customers what is the best way to get to higher-density 100 gigabit,” says Ward. “I point to the 400 gigabit DR4, even though we call it a 400-gigabit part, it is also a 4x100-gigabit DR solution.”
Ward says that the 500m reach of the DR is sufficient for the vast majority of links in the data centre.
SFP56 SR and LR
Finisar has also demonstrated two SFP56 modules: a short reach (SR) version that has a reach of 100m over OM4 multi-mode fibre and the 10km LR single-mode interface. The SR is VSCEL-based while the LR uses a directly-modulated distributed feedback laser.
The SFP is deployed widely at speeds up to and including 10 gigabits while the 25-gigabit SFP shipments are starting to ramp. The SFP56 is the next-generation SFP module with a 50-gigabit electrical input and a 50-gigabit PAM-4 optical output.
The SFP56 will be used for several applications, says Finisar. These include linking servers to switches, connecting switches in enterprise applications, and 5G wireless applications.
Finisar says its 50 and 100 gigabit-per-lane products will likely be released throughout 2019, in line with the industry. “The 8-channel devices will likely come out at least a few quarters before the 4-channel devices,” says Ward.
Finisar's 10 Gig bi-directional DWDM architecture
Finisar has developed a bi-directional 10-gigabit SFP+ module for the metro-access market. The dense wavelength-division multiplexing (DWDM) module is designed to expand capacity at locations where fibre is scarce. And being tunable, the SFP+ also simplifies network planning for the operators.
Finisar demonstrated the module working at the recent ECOC 2017 show held in Gothenburg.
Market applications
Interest is growing in using WDM optics for wireless, metro-access and cable networks that are undergoing upgrades. The interest in WDM at the network edge is due to a need to use fibre resources more efficiently. “We are seeing that globally, more and more dark fibre is being used up,” says Leo Lin, director of product line management at Finisar.
Leo LinGiven the cost of leasing and installing fibre, operators are keen to make the best use of their existing fibre and are willing to pay more for WDM optics.
According to Finisar, leasing a fibre can cost $250-$2,000 per fibre annually while the cost of installing fibre can be $500,000 per 10km. “Using WDM optics, you can get payback in less than a year,” says Lin.
LightCounting Market Research's latest forecast estimates that the global wireless transceiver market for 10 gigabit WDM will be approximately $400 million in 2022.
Finisar’s bi-directional 10-gigabit SFP+ product is also being aimed at two emerging ITU Telecom standards: G.metro and NG-PON2.
G.Metro and NG-PON2
The G.metro standard supports up to 40 DWDM wavelengths on a 100GHz wavelength grid. Tuneable transponders each at 10 gigabits-per-second (Gbps) are used and have a reach of up to 20km without amplification.
NG-PON2 is a time and wavelength division multiplexing, passive optical network (TWDM-PON) standard. “In addition to TWDM-PON, they want to have a few dedicated point-to-point WDM links, an overlay on top of the PON,” says Lin.
G.metro uses both the C-band and the L-band: one band is used for the sent wavelengths and the other band for the received wavelengths. In contrast, Finisar’s bi-directional approach sends and receives wavelengths using the C-band only.
“The G.metro standard calls out bi-directional and tuneable optics, and our bi-directional module product can be directly used here,” says Lin. “Since ECOC, we have had quite some support from operators and OEMs that will add our architecture as one of the channel options in both G.metro and NG-PON2.”
Bidi design
Finisar describes its design as a dual-band bi-directional DWDM approach. To understand the design, it helps to compare it to existing DWDM duplex and single fibre schemes.
Standard DWDM (A), a hybrid bi-directional scheme that uses 50GHz AWGs (B), and the bi-directional approach (C) using the C- and L-bands being proposed for G.metro and NG-PON2. Finisar's approach is shown in the diagram below. Source Finisar.
With standard DWDM, two fibres are used, each having a multiplexer and demultiplexer pair. The C-band is used with wavelengths sent down one fibre and received on the other (see diagram A).
The hybrid bi-directional DWDM design (diagram B) sends wavelengths in both directions on one fibre. The hybrid approach is growing in popularity, says Finisar, to address fibre scarcity, for example between a central office and a remote node. For the hybrid scheme, only a single multiplexer-demultiplexer pair is needed. But to fit all the wavelengths on one fibre, a 50GHz channel mux-demux is used rather than a cheaper 100GHz one.
Another bi-directional scheme - one that G.metro and NG-PON2 are promoting - uses 100GHz channels but requires both the C-band and the L-band (diagram C). Here, east-to-west traffic is sent across one band while west-to-east traffic is sent on the other.
“This approach requires cyclic arrayed-waveguide gratings,” says Lin. A cyclic or colourless arrayed-waveguide grating (AWG) can separate or combine wavelengths across multiple bands. But unlike the hybrid bi-directional case, one fibre only connects to each bi-directional transceiver hosting a C-band wavelength in one direction and an L-band one travelling in the opposite direction. Using fewer fibres saves cost and space.
Finisar’s bi-directional design is similar but with one important twist: only the C-band is used.
To do this, two carriers are placed into the single 100GHz channel: one an upstream wavelength and one a downstream one. The result is 40, 10Gbps wavelengths - 80 carriers in total - spread across the C-band (see diagram below).
Finisar's bi-directional architecture uses two carriers per channel spread across the C-band. Source: Finisar
A tuneable filter is used in the module not only to match the channel that the remote module’s tuneable laser will use, but also to select the particular band in a given channel, either the upstream or downstream band. The result is that one bi-directional module can be used for all 40 channels. “One single part number for the far end and the near end,” says Lin.
The technical challenge Finisar faced to make its design work is separating the two closely spaced carriers in a 100GHz channel.
Finisar says that with a 50GHz DWDM system, the wavelength must sit centrally in the channel and that requires a wavelength locker. The two carriers within its 100GHz band are not placed centrally yet Finisar has developed a way to separate the two without needing wavelength-locker technology.
The tuneable bi-directional approach also simplifies network planning. If an operator wants to add a new wavelength and drop it at an existing node, the node’s optical add-drop multiplexer does not need to be upgraded.
“All operators have different channel plans and customised optical add-drop multiplexers in the field,” says Lin. “In our case, we are even simpler than the duplex. In duplex you need a multiplexer-demultiplexer pair; in our case, any AWG or thin-film filter based design can be used.”
Finisar uses an out-of-band communication channel for the central office module to co-ordinate the channel to be used with a newly inserted remote module. “You can plug in a module on any available port and it establishes a link by itself in under 10 seconds,” says Lin.
Roadmap
Finisar is working to extend the reach of its 10-gigabit bi-directional tuneable SFP+ DWDM architecture to beyond the current 40km to 60km with the use of a bi-directional EDFA.
The current 40km reach is determined by the link budget chosen for the expected use cases with the assumption being that multiple add-drop sites will exist between the central office and the remote end. “The tuneable laser used is the same that is used in our tuneable XFP+, so supporting beyond 80km is not a problem,” says Lin.
Finisar says it is working on a 25-gigabit bi-directional module that will be available in 2019.
Meanwhile, select customers are evaluating samples of the 10-gigabit bi-directional SFP+ module. General availability is expected by mid-2018.
Books of the year 2016 - Part 2
Simon Poole, director, new business ventures, Finisar Australia
The highlight of the year in fiction was reading The Shepherds’ Crown, the last of the Discworld novels from the wonderful Terry Pratchett. He, along with his cast of extraordinary characters, including the marvellous Tiffany Aching – a fabulous role model for teenage girls, held up a mirror to the foibles and strengths of our humanity, and will be sorely missed.
Farewell also to the fearless Christoph Hitchens; re-reading God is not Great reminded me of the strengths of his analysis and the importance of ethics and morals in our dealings with each other.
From a work perspective, The Other Side of Innovation: Solving the Execution Challenge by Vijay Govindarajan and Chris Trimble is one of the few books about innovation that tries to address the real issues which are, to my mind, around the implementation of the ideas rather than their generation. Recommended for anyone who has to manage innovation within an existing organisation with all its strengths and weaknesses.
Loudon Blair, senior director, corporate strategy office, Ciena
Three books read this year caused me to innocently stumble upon a recurring theme of how we are responding to rapid advances in communications technology.
As an adult, reading the 19th century classic, Alice’s Adventures in Wonderland by Lewis Carroll, provided a fascinating insight into Carroll’s creative mind. I was especially intrigued by how he plays with the reader’s interpretation of the English language - how we can say one thing and be understood to have said something else. It is a reminder in these days of email misinterpretation and text shorthand to be clear about what we intend to communicate.
The Alchemist by Paulo Coelho is a story of a shepherd boy seeking his personal legend and has multiple layers of interpretation. Coelho talks about how your personal legend is something that you have always wanted to accomplish. You know what it is when you are young because, at that age, everything is possible. But as you get older, you can lose track of your goal as some “mysterious force” convinces you that it is impossible to realize. However, Coelho says that when you really want something, “the universe conspires in helping you achieve it”.
I think there is a lot to be said for this idea that there is a universe of help out there to steer us towards our goals. As a society, we have never been more connected. Through the Internet and social networks, we have created a highly interactive and diverse networking universe which helps us attain our goals on a daily basis.
Drive: The Surprising Truth About What Motivates Us by Daniel H. Pink explores the issue of motivation in the workplace. Pink discusses how, as society evolves, traditional motivational techniques that may have been useful in the past, can be counter-productive in the future.
His discussion on how our workplace is evolving from routine rule-based tasks to non-routine conceptual tasks sidetracked me on to a commonly explored concern today about how artificial intelligence and robotics may replace many of today’s jobs.
As an engineer working to develop the next generation of the Internet, this caused me to reflect on the responsibility and implications of the future we will create as technical innovators.
OIF starts work on a terabit-plus CFP8-ACO module
The Optical Internetworking Forum (OIF) has started a new analogue coherent optics (ACO) specification based on the CFP8 pluggable module.
The CFP8 is the latest is a series of optical modules specified by the CFP Multi-Source Agreement and will support the emerging 400 Gigabit Ethernet standard.
Karl GassAn ACO module used for optical transport integrates the optics and driver electronics while the accompanying coherent DSP-ASIC residing on the line card.
Systems vendors can thus use their own DSP-ASIC, or a merchant one if they don’t have an in-house design, while choosing the coherent optics from various module makers. The optics and the DSP-ASIC communicate via a high-speed electrical connector on the line card.
ACO design
The OIF completed earlier this year the specification of the CFP2-ACO.
Current CFP2-ACO modules support single-wavelength transmission rates from 100 gigabit to 250 gigabit depending on the baud rate and modulation scheme used. The goal of the CFP8-ACO is to support up to four wavelengths, each capable of up to 400 gigabit-per-second transmissions.
This project is going to drive innovation
“This isn’t something there is a dire need for now but the projection is that this will be needed in two years’ time,” says Karl Gass of Qorvo and the OIF Physical and Link Layer Working Group optical vice chair.
OIF members considered several candidate optical modules for the next-generation ACO before choosing the CFP8. These included the existing CFP2 and the CFP4. There were some proponents for the QSFP but its limited size and power consumption is problematic when considering long-haul applications, says Gass.
Source: Finisar
One difference between the CFP2 and CFP8 modules is that the electrical connector of the CFP8 supports 16 differential pairs while the CFP2 connector supports 10 pairs.
“Both connectors have similar RF performance and therefore can handle similar baud rates,” says Ian Betty of Ciena and OIF board member and editor of the CFP2-ACO Implementation Agreement. To achieve 400 gigabit on a wavelength for the CFP8-ACO, the electrical connector will need to support 64 gigabaud.
Betty points out that for coherent signalling, four differential pairs per optical carrier are needed. “This is independent of the baud rate and the modulation format,” says Betty.
So while it is not part of the existing Implementation Agreement, the CFP2-ACO could support two optical carriers while the CFP8 will support up to four carriers.
“This is only the electrical connector interface capacity,” says Betty. “It does not imply it is possible to fit this amount of optics and electronics in the size and power budget.” The CFP8 supports a power envelope of 20W compared to 12W of the CFP2.
The CFP2-ACO showing the optical building blocks and the electrical connector linking the module to the DSP-ASIC. Source: OIF
The CFP8 occupies approximately the same area as the CFP2 but is not as tall such that the module can be doubled-stacked on a line card for a total of 16 CFP8-ACOs on a line card.
Given that the CFP8 will support up to four carriers per module - each up to 400 gigabit - a future line card could support 25.6 terabits of capacity. This is comparable to the total transport capacity of current leading dense WDM optical transport systems.
Rafik Ward, vice president of marketing at Finisar, says such a belly-to-belly configuration of the modules provides future-proofing for next-generation lineside interfaces. “Having said that, it is not clear when, or how, we will be able to technically support a four-carrier coherent solution in a CFP8 form factor,” says Ward.
Oclaro stresses that such a high total capacity implies that sufficient coherent DSP silicon can fit on the line card. Otherwise, the smaller-height CFP8 module may not enable the fully expected card density if the DSP chips are too large or too power-hungry.
OIF goal
Besides resulting in a higher density module, a key OIF goal of the work is to garner as much industry support as possible to back the CFP8-ACO. “How to create the quantity of scale so that deployment becomes less expensive and therefore quicker to implement,” says Gass.
The OIF expects the work to be similar to the development of the CFP2-ACO Implementation Agreement. But one desired difference is to limit the classes associated with the module. The CFP2-ACO has three class categories based on whether the module has a limited and linear output. “The goal of the CFP8-ACO is to limit the designs to single classes per wavelength count,” says Gass.
Gass is looking forward to the CFP8-ACO specification work. Certain standards efforts largely involve making sure components fit into a box whereas the CFP8-ACO will be more engaging. “This project is going to drive innovation and that will drive some technical work,” says Gass.
ECOC '15 Reflections: Part 2
Martin Zirngibl, head of network enabling components and technologies at Bell Labs.
Silicon Photonics is seeming to gain traction, but traditional component suppliers are still betting on indium phosphide.
There are many new start-ups in silicon photonics, most seem to be going after the 100 gigabit QSFP28 market. However, silicon photonics still needs a ubiquitous high-volume application for the foundry model to be sustainable.
There is a battle between 4x25 Gig CWDM and 100 Gig PAM-4 56 gigabaud, with most people believing that 400 Gig PAM-4 or discrete multi-tone with 100 Gig per lambda will win.
Will coherent make it into black and white applications - up to 80 km - or is there a role for a low-cost wavelength-division multiplexing (WDM) system with direct detection?
One highlight at ECOC was the 3D integrated 100 Gig silicon photonics by Kaiam.
In coherent, the analogue coherent optics (ACO) model seems to be winning over the digital coherent one, and people are now talking about 400 Gig single carrier for metro and data centre interconnect applications.
As for what I’ll track in the coming year: will coherent make it into black and white applications - up to 80 km - or is there a role for a low-cost wavelength-division multiplexing (WDM) system with direct detection?
Yukiharu Fuse, director, marketing department at Fujitsu Optical Components
There were no real surprises as such at ECOC this year. The products and demonstrations on show were within expectations but perhaps were more realistic than last year’s show.
Most of the optical component suppliers demonstrated support to meet the increasing demand of data centres for optical interfaces.
The CFP2 Analogue Coherent Optics (CFP2-ACO) form factor’s ability to support multiple modulation formats configurable by the user makes it a popular choice for data centre interconnect applications. In particular, by supporting 16-QAM, the CFP2-ACO can double the link capacity using the same optics.
Lithium niobate and indium-phosphide modulators will continue to be needed for coherent optical transmission for years to come
Recent developments in indium phosphide designs has helped realise the compact packaging needed to fit within the CFP2 form factor.
I saw the level of integration and optical engine configurations within the CFP2-ACO differ from vendor to vendor. I’m interested to see which approach ends up being the most economical once volume production starts.
Oclaro introduced a high-bandwidth lithium niobate modulator for single wavelength 400 gigabit optical transmission. Lithium niobate continues to play an important role in enabling future higher baud rate applications with its excellent bandwidth performance. My belief is that both lithium niobate and indium-phosphide modulators will continue to be needed for coherent optical transmission for years to come.
Chris Cole, senior director, transceiver engineering at Finisar
ECOC technical sessions and exhibition used to be dominated by telecom and long haul transport technology. There is a shift to a much greater percentage focused on datacom and data centre technology.
What I learned at the show is that cost pressures are increasing
There were no major surprises at the show. It was interesting to see about half of the exhibition floor occupied by Chinese optics suppliers funded by several Chinese government entities like municipalities jump-starting industrial development.
What I learned at the show is that cost pressures are increasing.
New datacom optics technologies including optical packaging, thermal management, indium phosphide and silicon integration are all on the agenda to track in the coming year.
STMicro chooses PSM4 for first silicon photonics product
- Lowers the manufacturing cost of optical modules
- Improves link speeds
- Reduces power consumption
STMicro's in-house silicon photonics EDA. "We will develop the EDA tools to the level needed for the next generation products," says Flavio Benetti.
Transmode adopts 100 Gigabit coherent CFPs
Transmode has detailed line cards that bring 100 Gigabit coherent CFP optical modules to its packet optical transport platforms.
We can be quicker to market when newer DSP-based CFPs appear
Jon Baldry
"We believe we are the first to market with line-side coherent CFPs, bringing pluggable line-side optics to a WDM portfolio," says Jon Baldry, technical marketing director at Transmode. Baldry says that other system vendors already support non-coherent CFP modules on their line cards and that further vendor announcements using coherent CFPs are to be expected.
The Swedish system vendor announced three line cards: a 100 Gig transponder, a 100 Gig muxponder and what it calls its Ethernet muxponder (EMXP) card. The first two cards support wavelength division multiplexing (WDM) Layer 1 transport: the 100 Gig transponder card supports two 100 Gig CFP modules while the 100 Gig muxponder supports 10x10 Gig ports and a CFP.
The third card, the EMXP220/IIe, has a capacity of 220 Gig: 12x10 Gigabit Ethernet ports and the CFP, with all 13 ports supporting optional Optical Transport Network (OTN) framing. "You can think of it as a Layer 2 switch on a card with 13 embedded transponders," says Baldry. The three cards each take up two line card slots.
Transmode's platforms are used for metro and metro regional networks. Metro has more demanding cost, space and power efficiency requirements than long distance core networks. "The move that the whole industry is taking to CFP or pluggable-based optics is a big step forward [in meeting metro's requirements]," says Baldry.
The line cards will be used with Transmode's metro edge TM-Series packet optical family that is suited for applications such as mobile backhaul and business services. "Within packet-optical networks, we can do customer premise Gigabit Ethernet all the way through to 100 Gig handover to the core on the same family of cards running the same Layer 2 software," says Baldry. Transmode believes this capability is unique in the industry.
The TM-3000 chassis is 11 rack units (RU) high and can hold eight double-slot cards, for a total of 800 Gig CFP line side capacity.
Source: Transmode
100 Gig coherent modules
Transmode is talking to several 100 Gig coherent CFP module makers. The company will use multiple suppliers but says it is currently working with one manufacturer whose product is closer to market.
Acacia Communications announced the first CFP module late last year and other module makers are expected to follow at the upcoming OFC show in March 2014.
The roadmap of the CFP modules envisages the CFP to be followed by the smaller CFP2 and smaller still CFP4. For the CFP2 and CFP4, the coherent digital signal processor (DSP) ASIC is expected to be external to the module's optics, residing on the line card instead. The 100 Gig CFP, however, integrates the DSP-ASIC within the module and this approach is favoured by Transmode.
"We can be quicker to market when newer DSP-based CFPs appear; today we can do 800km and in the future that will go to a longer reach or lower power consumption," says Baldry. "Also, the same port can take a coherent CFP or a 100BASE-SR4 or -LR4 CFP without having the cost burden of a DSP on the card whether it is needed or not."
The company also points out that by using the integrated CFP it can choose from all the coherent designs available whereas modules that separate the optics and DSP-ASIC will inevitably offer a more limited choice.
There are also 100 Gigabit direct detection CFPs from the likes of Finisar and Oplink Communications and Transmode's cards would support such a CFP module. But for now the company says its main interest is in coherent.
"One key requirement for anything we deploy is that it works with the existing optical infrastructure," says Baldry. "One difference between 100 Gig metro and long haul is that a lot of the long distance 100 Gig is new build, whereas the metro will require 100 Gig over existing infrastructure and coherent works very nicely with the existing design rules and existing 10 Gig networks."
The 100 Gig transponder card consumes 75W, with the coherent CFP accounting for 30W of the total. The card can be used for signal regeneration, hosting two 100 Gig coherent CFPs rather than the more typical arrangement of a client-side and a line-side CFP. The card's power consumption exceeds 75W, however, when two coherent CFPs are used.
The 100 Gig transponder and Ethernet muxponder will be available in the second quarter of 2014, says Transmode, while the 100 Gig muxponder card will follow early in the third quarter of the year.
MultiPhy eyeing 400 Gig after completing funding round
MultiPhy is developing a next-generation chip design to support 100 and 400 Gigabit direct-detection optical transmission. The start-up raised a new round of funding in 2013 but has neither disclosed the amount raised nor the backers except to say it includes venture capitalists and a 'strategic investor'.
The start-up is already selling its 100 Gig multiplexer and receiver chips to system vendors and module makers. The devices are being used for up to 80km point-to-point links and dense WDM metro/ regional networks spanning hundreds of kilometers. "In every engagement we have, the solutions are being sold in both data centre and telecom environments," says Avi Shabtai, CEO of MultiPhy.
The industry has settled on coherent technology for long-distance 100 Gig optical transmission but coherent is not necessarily a best fit for certain markets if such factors as power consumption, cost and compatibility with existing 10 Gig links are considered, says Shabtai.
The requirement to connect geographically-dispersed data centres has created a market for 100 Gig direct-detection technology. The types of data centre players include content service providers, financial institution such as banks, and large enterprises that may operate their own networks.
In every engagement we have, the solutions are being sold in both data centre and telecom environments
MultiPhy's two chips are the MP1101Q, a 4x25 Gig multiplexer device, and the MP1100Q four-channel receiver IC that includes a digital signal processor implementing the MLSE algorithm.
The chipset enables 10 Gig opto-electronics to be used to implement the 25 Gig transmitter and receiver channels. This results in a cost advantage compared to other 4x25 Gig designs. A design using the chipset can achieve 100 Gig transmissions over a 200GHz-wide channel or a more spectrally efficient 100GHz one. The latter achieves a transmission capacity of 4 Terabits over a fibre.
ADVA Optical Networking is one system vendor offering 100 Gig direct-detection technology while Finisar and Oplink Communications are making 100 Gigabit direct-detection optical modules. Oplink announced that it is using MultiPhy's chipset in 2013.
Overall, at least four system vendors are in advanced stages of developing 100 Gig direct-detection, and not all will necessarily announce their designs, says Shabtai. Whereas all the main optical transmission vendors have 100 Gig coherent technology, those backing 100 Gig direct detection may remain silent so as not to tip off their competitors, he says.
We assume we can do more using those [25 Gig] optical components with our technology
Meanwhile, the company is using the latest round of funding to develop its next-generation design. MultiPhy is focussed on high-speed direct-detection despite having coherent technology in-house. "Coherent is on our roadmap but direct detection is a very good opportunity over the next two years," says Shabtai. "You will see us come with solutions that also support 400 Gig."
A 400 Gigabit direct-detection design using its next generation chipset will likely come to market only in 2016 at the earliest by which time 25 Gig components will be more mature and cheaper. Using existing 25 Gig technology, a 400 Gig design requires 16, 25 Gig channels. However, the company will likely extend the performance of 25 Gig components to achieve even faster channel speeds, just like it does now with 10 Gig components to achieve 25 Gig speeds. The result will be a 400 Gig design with fewer than 16 channels. "We assume we can do more using those [25 Gig] optical components with our technology," says Shabtai.