Skip to main content

The Path to 100G Single Lambda in the Data Center - Part 5

Published Date

AFL Reflections
Maury Wood, Test & Inspection
September 2017
 
The Path to 100G Single Lambda (100GSL™) in the Data Center

As we resume this blog series, before jumping back into the 100G single lambda signal chain, it makes sense to summarize some of the 100G single lambda (100GSL™) announcements made during the summer of 2017.  There has been great deal of activity in the electro-optic component and subsystem segments relating to this next generation leap forward – turns out that 100G single lambda is a super-hot topic in Fall 2017. As the EO components are enabling ingredients in next gen 100G single lambda transceivers, assessing commercial status is worthwhile in terms of helping to predict system-level timelines for this exciting technology.

By way of context, in 2014, Scott Kipp, President of the Ethernet Alliance (EA), presented a paper entitled "Ethernet Alliances 100 GbE Challenges" (http://www.ethernetalliance.org/wp-content/uploads/2013/04/Ethernet-Alliance-100GbE-Challenges-09-16-14.pdf).  In it, he described what he called the "100 GbE Single Lambda Holy Cup".  Ostensibly, the Ethernet Alliance will award this cup to "The first company to publicly demonstrate a 100GbE Single Lambda in a 3.5W QSFP28" MSA pluggable transceiver module.  Requirements to win include:

  • Use of CAUI (25 Gbps CAUI-4 or 50 Gbps CAUI-2 presumably, possibly 100 Gbps CAU-1) electrical interface lanes
  • Reach of 2km over duplex SMF with a 4.0 dB (or less) insertion loss or 100m over duplex MMF with a 2.0 dB insertion loss

The EA has a similar challenge (which Kipp dubbed the Holy Grail) outstanding for a 1.5W 100GbE SFP+ MSA pluggable transceiver module using CAUI with similar reach criteria.  While the industry has moved on to other transceiver MSAs, now three years after this call to action, the EA’s intent is clear.

Ethernet Alliance

Earlier this summer, Source Photonics wrote a blog post on this quest to 100G single lambda, by way of highlighting their R&D efforts to help facilitate this technological benchmark.  As this series has highlighted, Source Photonics makes clear that 53GBaud PAM4 modulation is fundamental to this goal.  They also highlight their InP electro-absorption (EA) modulated laser (EML) TOSA and PIN photodiode ROSA.  The single chip EML integrates a DFB laser plus EA Mach-Zehnder (M-Z) modulator, and Source Photonics claims a pre-FEC BER better than 1 x 10-5 (compliant to KP4 threshold), impressive 6 dB link budget, and with power consumption on SMF consistent with the 3.5W target.  Source Photonics demonstrated this solution with MACOM at OFC in March 2017.  Source Photonics also makes clear the importance of complex DSP-based equalization methods and FEC to achieve the 100G single lambda goal.  Source Photonics and Credo jointly demonstrated 100G single lambda technology at ECOC17 in Gothenburg, Sweden.

MACOM has emerged as a key innovator of 100G single lambda components.  While perhaps best known as a broad line microwave and millimeter wave IC supplier, their recent acquisition of Applied Micro (APM) has given them world-class DSP capability.  Their 100G single lambda chipset includes the 16 mm FinFET process PRISM "mixed signal PHY" that comprises multiple functions: PAM4 signal digital mod, linear (analog) laser mod, FEC processor, and digital EQ.  On the integrated optics side, MACOM has a wafer scale laser and fiber alignment technology called Etched Facet Technology.  MACOM also offers a set of companion 53GBaud TIAs, PIN photodiodes, TOSAs and ROSAs.

MultiPHY announced their 16 nm MPF3101 “FlexPhy” PAM4 DSP at the recent ECOC17 show, and Lightwave Logic used the same occasion to announce their 50GBaud polymer ridge waveguide M-Z modulator.  As might be expected, FlexPhy includes on-chip ultra-high speed ADCs and DACs, a Reed Solomon (544, 514) FEC engine, and patented equalization engines.

The Polaris is Inphi's 16 nm PAM4 DSP for 100G single lambda, announced in March 2017 along with companion linear drivers and linear TIAs. Polaris is congfigurable engine with 28GBaud and NRZ electrical interfaces with retiming and gearbox functionality to support multiple transciever MSAs.

Twenty-two companies announced their participation in the 100G Lambda MSA initiative on September 12, 2017.  This new MSA is aligned to the forthcoming 100GBASE-DR (100 Gbps single lambda spanning 500m on SMF) and 400GBASE-DR4 (4 x 100 Gbps single lambda spanning 500m on SMF) standards from the IEEE 802.3 committee.  Not surprisingly, PAM4 signaling and Reed Solomon (544, 514) Forward Error Correction is specified.

These and other announcements (from Finisar, Inphi, Applied Optoelectronics, et al.) are the precursor to commercial transceiver announcements likely in 1H2018.  It looks like 2019 will be a full year of single lambda 100G deployment, with the implication that 200G (four fiber duplex), 400G (eight fiber duplex) and 800G (16 fiber duplex) short and medium reach links start to become cost effective in hyperscale data centers.  The 100G single lambda quest is accelerating, and AFL looks forward to supplying "AFL 100GSL Ready" products and services in support of this exciting next generation fiber optics communication technology!