How scaling optical networks is soon to change

Carrier division multiplexing and spatial division multiplexing (CSDM) are both needed, argues Lumentum’s Brian Smith.

The era of coherent-based optical transmission as is implemented today is coming to an end, argues Lumentum in a White Paper. 

Brian Smith

The author of the paper, Brian Smith, product and technology strategy, CTO Office at Lumentum, says two factors account for the looming change.

One is Shannon’s limit that defines how much information can be sent across a communications channel, in this case an optical fibre.

The second, less discussed regarding coherent-based optical transport, is how Moore’s law is slowing down.

”Both are happening coincidentally,” says Smith. “We believe what that means is that we, as an industry, are going to have to change how we scale capacity.”

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Xtera demonstrates 40 Terabit using Raman amplification

Feature: 100 Gig and Beyond. Part 2

• Xtera's Raman amplification boosts capacity and reach
• 40 Terabit optical transmission over 1,500km in Verizon trial
• 64 Terabit over 1,500km in 2015 using a Raman module operating over 100nm of spectrum  

Herve Fevrier

Optical transport equipment makers continue to research techniques to increase the data carried long distances over a fibre without sacrificing reach. The techniques include signal processing of the transmit signal to cram data-carrying channels closer in the C-band, advanced soft-decision forward error correction (SD-FEC) and receiver signal processing to counter transmission impairments.

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The great data rate-reach-capacity tradeoff

Source: Gazettabyte

Optical transmission technology is starting to bump into fundamental limits, resulting in a three-way tradeoff between data rate, reach and channel bandwidth.

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