Silicon Photonics for HPC Interconnects, 100 Gbps and Beyond

Silicon Photonics for HPC Interconnects, 100 Gbps and Beyond

Brian [email protected]

1

Luxtera Company Overview

• Founded: 2001Spin Out from Caltech

• Headquarters

• Pioneered a new class of Semiconductor “Silicon CMOS Silicon CMOS Photonics”Photonics”• Headquarters

Carlsbad, CA

• Privately HeldShipping product for revenue

PhotonicsPhotonicsEnables Single CMOS chip opto-electronic transceiverBreaks both performance andShipping product for revenue Breaks both performance and price/performance barriers

• Strong Intellectual Property PortfolioPortfolio

Over 80 US Patents issuedOver 40 additional pending

2Brian Welch, [email protected]

Overview

• Motivations– IBTA Interconnect Roadmap

• Silicon Photonics– Technology Summary

• Contemporary Applications– 40 Gbps QSFP Active Optical Cables

• Next Generation Solutions– 25 Gbps per lane interconnects

• Beyond 25 Gbps


Motivations

• Enterprise interconnect throughput has increased by over 10x in the last d ddecade– From 10Gbps per link to 120

Gbps• Within two years solutionsWithin two years solutions

capable of over 300 Gbps will be required– Next generation enterprise

CPUs can deliver up to 320CPUs can deliver up to 320 Gbps of signaling

• Ability to scale out is limited, driving the need for d ti ll hi h i l

InfiniBand IBTA Roadmap Plans for 100G dramatically higher serial rates– Over 25 Gbps per Lane

EDR need for 2011


TECHNOLOGY SUMMARYSilicon Photonics

TECHNOLOGY SUMMARY

Brian Welch, [email protected] 5

Silicon Photonics

• Silicon Photonics is a scalable platform capable of meeting the increasing needs of the enterprise world.

– Silicon Photonics has near infinite optical bandwidth.

Sili Ph t i l ith th ITRS d• Silicon Photonics scales with the ITRS roadmap, ensuring interconnects will not be the limiting factor in fabric developmentfactor in fabric development.

– Silicon Photonics scaling is cost neutral– Silicon Photonics scaling is cost neutral.


Silicon Photonics

Fully Integrated CMOSPhotonic, Analog & Digital Circuits

Standard CMOS Analog & Digital Circuits

Silicon Photonic Circuits

EPIC – Electro Photonic Integrated Circuit

Silicon Photonics

==++Waveguides Waveguide Structures

Vertical Couplers High/Low Speed Modulators

Added to standard Silicon Enables: Low‐cost highIntegrated PD & TIA/LAWaveguide Photo‐detectors

Luxtera’s CMOS Photonics technology

Added to standard Silicon CMOS chip fab and CMOS chip design flow

Enables: Low cost, high volume optics platform


Photonics and Electronics on a Common Wafer

Based on Commercial Process :• “Photonically-enabled” CMOS process

• “Pluggable” process modules added for photonicsgg p p• All processes and tools used are standard and fully

compatible with CMOS

Based on Commercial Process :“Photonically-enabled” CMOS process

“Pluggable” process modules added for photonicsAll processes and tools used are standard and fully

Poly Gate ContactsMetal 1

GeField Oxide

Salicide Block

p ocesses a d too s used a e sta da d a d u ycompatible with CMOS

Buried Oxide

Active Si

Si Substrate


Silicon Photonics Key Components

25G Integrated Photodiodes25G MZ Modulators


Wafer‐Scale TestingVertical Optical Coupling

Low Cost Light Sources for CMOS Photonics

• Integration of light sources with CMOS photonics:

• CW Laser always on – Like a DC

• For multi‐channel transceivers a single laser can be shared between the channels reducing laser costCW Laser always on Like a DC

power supply• Since the laser is always on, no need

for expensive high‐speed Lasers

the channels reducing laser cost

Micro‐packaged laser: Flip‐chip laser:Light Source

Passive Splitters 8 MZI

ModulatorsOptical

Interfaces


40 GBPS QSFP AOCContemporary Applications

40 GBPS QSFP AOC


Blazar 40 Gbps QSFP AOCLowest Power:

780 mW typical; 1.09 W MaxLongest Reach:

Up to 4,000 metersUp to 4,000 metersSingle Mode Fiber

Lowest Bit Error Rate:<10-15 Bit-Error Rate

Lowest Latency:QSFP PluggableQSFP Pluggable Lowest Latency:340ps per TX, 340ps per RX5ns per meter of fiber

High Bandwidth:42 Gbps (4 x 10 52 Gbps)

Q ggQ ggActive Cable AssemblyActive Cable Assembly

24 AWG Passive Copper<7m 42 Gbps (4 x 10.52 Gbps)

Standards Compliant: QSFP MSA mechanical complianceEthernet SFP+ compliant electrical interface

<7m

32 AWG Active Copper

<12mFiber4,000m

IBTA QDR compliant (UNH Certified)High Reliability:

MTBF > 5 Million hoursFIT < 200

12

Blazar 4x10 Gbps Silicon Photonics IC

Unprecedented Opto/Electronic CMOS IntegrationOptics• Fiber coupled directly to the die• Integrated wave guides• Integrated modulators• Integrated photo‐detectors

Analog and Digital Electronics

4x10 Gb/sElectricalSFP+

DigitalAnalog and Digital Electronics

• Integrated modulator driver

• Integrated amplifiers

• Integrated digital functions

Receivers

Transmitters O ti l

DigitalCore

• Integrated digital functions

Applications

• QDR 40G InfiniBand

• 4x10G and 40G Ethernet

4x10 Gb/sElectricalSFP+

Transmitters OpticalInterfaces

• PCIe Extensions

• 4x8G Fibre Channel

Monolithically integrated in mainstream SOI CMOS


Monolithically integrated in mainstream SOI CMOS

Blazar MSA Compliant Packaging


25 GBPS PER LANENext Generation Solutions

25 GBPS PER LANE INTERCONNECTS


Challenges of Scaling in Conventional Technologies

• Copper Interconnects:– Increasing lane rates drives the need for heavier

gauge wiring, and/or shorter lengths– Increasing lane count increases fiber bulk and

decreases usabilitydecreases usability• Multi-Mode Interconnects:

– Increasing lane rate puts pressure on high speedIncreasing lane rate puts pressure on high speed VCSELs, mandating higher current densities

– Fiber core and photodiode spot sizes need to reduce to enable rate scaling


Advantages of Silicon Photonics

• Silicon Photonics only requires electrical scaling with increased data rate.– Silicon Photonics optical components have OE

bandwidth far beyond any near term needs (over 100 GHz)GHz)

– Silicon Photonics interfaces and medium remain constant irrespective of rate

• Single mode fiber and waveguide type photodiodes

– Silicon Photonics light sources are unmodulated, and require no modification to support higher ratesrequire no modification to support higher rates


Silicon Photonics at 25 Gbps

Luxtera’s Silicon Photonics is EDR InfiniBand Ready Now!

• Clean Transmitter and Receiver E l ith L Jitt R lt

Demonstrated 25G Performance

Eye along with Low Jitter Results in:

– Low Bit Error Rate– Long Reach

• No need for faster lasers– Current CW lasers can be reused

• Single Mode fiber is future proof– Over 2 Terabyte capable

• No significant incremental cost gover 40G

– Same Die size– Same Laser– Same Fiber


INFINIBAND HDR AND OTHERBeyond 25 Gbps

INFINIBAND HDR AND OTHER ADVANCED FABRICS


Beyond 25 Gbps

• HDR tentatively scheduled for 2014

il bilitavailability• HDR likely to push

signaling rates beyond 40signaling rates beyond 40 Gbps– Over 400 Gbps aggregate

interconnect throughputinterconnect throughput

• Terabit cables needed within the coming InfiniBand IBTA Roadmap Plans for 100G within the coming decade? EDR need for 2011


Silicon Photonics for HPC Interconnects, 100 Gbps and Beyond

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