Gregory Fish, Aurrion Inc. USAOSA Optical Interconnects for Extreme-Scale Computing IncubatorAugust 9-11, 2015

Heterogeneous Photonic Integration for WDM based Optical Interconnects

Evolution of PhotonicsUsing the silicon manufacturing supply chain to make photonics

OSA Optical Interconnects for Extreme-Scale Computing Incubator, August 9-11, 2015

Conventional Silicon Photonics

In House Fabrication Foundry Infrastructure

Custom Packaging Techniques – Cooling, Gold Box Hermetic Packaging

OSAT Packaging - Self Hermetic, Uncooled

$$$$ $

Physics Based Simulations Silicon Based EDA

Transmission Line and decoupled drivers (cm) Electronic Co-design (<mm)

~10 pJ/bit ~pJ/bit

Heterogeneous Integration: Materials and Silicon Technologies

Heterogeneous Integration for Si photonic PICs: Combining multiple materials into a photonic circuit to use the best material for the function, while remaining compatible with Si foundry tools and processes.

Heterogeneous Electronic/Photonic Integration: Combining multiple Silicon technologies, including photonics together into a chip-scale microsystem.

OSA Optical Interconnects for Extreme-Scale Computing Incubator, August 9-11, 2015

Photonics

Heterogeneous Photonic Systems on Chip (SoC) Heterogeneous Electronic/Photonic System in Package (SiP)

NonlinearMaterials

DetectorsModulators &

Switches

Lasers

Low Loss Waveguides

Chip Produced in Silicon Foundry

MEMS

ITRS 2010Whitepaper

Hom

ogenous Integration

Heterogeneous Integration

4 fibers8 fibers

16 fibers

Scaling Bandwidth

OSA Optical Interconnects for Extreme-Scale Computing Incubator, August 9-11, 2015

25G

50G

100G

4 wavelengths8 wavelengths

16 wavelengths

Drivers for WDM in the Emerging Data Centers• Scale of largest Data Centers is driving

>500m interconnect lengths which requires Single Mode Fiber.

• IEEE Standards for SMF use WDM for reaches beyond 500m.

• 40G LR4 (10 km)• 100G LR4 (10km)• 400G FR8 (2km) & 400G LR8 (10km) (approved)

• Industry Standard based solutions need to be cost effective to avoid fragmentation.

1295 1300 1305 1310

-30

-20

-10

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wavelength (nm)

norm

aliz

ed p

ower

(dB

)

NRZ

1

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1295 1300 1305 1310

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-20

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norm

aliz

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ower

(dB

)

1270 1275 1280 1285 1295 1300 1305 1310

wavelength (nm)

3

2

1

0

PAM4

OSA Optical Interconnects for Extreme-Scale Computing Incubator, August 9-11, 2015

Enabling Uncooled WDM

OSA Optical Interconnects for Extreme-Scale Computing Incubator, August 9-11, 2015

Close integration of electronics and photonics

Lasers operating over a wide temperature range

[B. Koch et al., OFC 2013, PDP5C.8]

[B. Lee et al., OFC 2015, Tu3.G3]

Modulators operating over a wide wavelength range

Electronics-like packaging

Heterogeneous Components and Processing for Uncooled WDM

OSA Optical Interconnects for Extreme-Scale Computing Incubator, August 9-11, 2015

Active materials

defined by lithography

No critical alignment

Mature silicon photonics passives

Integration of multiple III-V

Materials

Reduced topology for

Standard Processing

Hermetic at Chip Scale

Wafer scale processing

Die PlacementSubstrate Removal

III-V ProcessingInterconnect

Heterogeneous Integration Process

Demonstration of an Heterogeneous Integration platform for Silicon Photonics

• Processed on Silicon wafers using Foundry Infrastructure.• Optimized III-V Materials for Active Components with Silicon Photonics.• Heterogeneous III-V Components on Silicon Match and even Exceed performance of Native III-V substrate.

Heterogeneous Integration:Platform and Component Library Overview

OSA Optical Interconnects for Extreme-Scale Computing Incubator, August 9-11, 2015

Laser and SOAs

Modulators

High Speed Photodiodes

Passives and MUX/DEMUX

0.80.9

11.11.21.31.41.5

0 500 1000 1500 2000 2500 3000

Ith/I

th0

Hours

Wavelength Stabilized

Heterogeneous Process is Reliable

High Temperature OperationUncooled Lasers on SiliconHeterogeneous O-Band Laser• Uncooled (no TEC)• > 40 dB side mode suppression• <400 kHz linewidth• RIN <-145 dB/√Hz• Laser diode efficiency: ~15% at T=80C• Reliability demonstrated:

• >4M laser accelerated aging device-hrsand counting

OSA Optical Interconnects for Extreme-Scale Computing Incubator, August 9-11, 2015

WDM Laser Arrays

High yield integrated laser breaks cost barrier• Large WDM arrays processed in parallel

Uncooled operation• Wavelength-locking across temperature

(20-80C) without a TEC• 200GHz (or 800GHz) grid

OSA Optical Interconnects for Extreme-Scale Computing Incubator, August 9-11, 2015

High Speed ModulatorsElectroabsorption Modulator (EAM)• >35GHz 3dB bandwidth• Vpp=1.0 V (>4dB ER), 2V (~9 dB ER)• Compact (<200um) , <3 dB IL• <0.5 pJ/bit at 32 Gb/s with CMOS driver

Mach-Zehnder Modulator (MZM)• 23 GHz, 3dB bandwidth • < 3 V for Pi phase shift• >15 dB ER• < 3 dB IL

OSA Optical Interconnects for Extreme-Scale Computing Incubator, August 9-11, 2015

25 Gb/s

28 Gb/s

30 Gb/s

32 Gb/s

35 Gb/s

>35GHz

See OFC2015 Paper Tu3G.3

High Speed Photodiodes

Heterogeneous Waveguide PD

• p-i-n photodiode with InGaAs absorber and Si waveguide layer

• 3dB bandwidth >35GHz

OSA Optical Interconnects for Extreme-Scale Computing Incubator, August 9-11, 2015

20 Gb/s

30 Gb/s

40 Gb/s

50 Gb/s

60 Gb/s

Low Loss Passives

• Low-loss (<1dB/cm) silicon waveguides and low-loss crossings.

• High yield complex MUX/DEMUX structures with 200mm fabrication tooling.

• Athermal operation for uncooled WDM.

OSA Optical Interconnects for Extreme-Scale Computing Incubator, August 9-11, 2015

MUX/DEMUX

IO Coupling

Heterogeneous Integrated Photonic Circuits and Packaging for Uncooled WDM

Heterogeneous Photonic Circuit Manufacturing• Silicon photonics PIC using foundries

• Assembly using silicon OSATs

• Complete BGA transceiver

• Low cost optical connector attach

OSA Optical Interconnects for Extreme-Scale Computing Incubator, August 9-11, 2015

ConclusionsWDM is effective and necessary approach for bandwidth scaling, yet brings challenges.

Heterogeneous Integration on Silicon Photonics addresses the challenges:• Cost effective integration of laser and other III-

V materials.

• Athermal and tunable optical elements for wavelength.

• Intimacy with electronics for control and signal integrity through advanced Si packaging.

OSA Optical Interconnects for Extreme-Scale Computing Incubator, August 9-11, 2015