1. Hybrid Photonic integration @ Huawei:
for optical transport & C2C
Photonic integration in Si and InP:
Overview of experience and expertise
Roman Malendevich
Confidential and proprietary 02/23/13

2. Outline
Si integration at Luxtera
InP integration at Infinera
• OOK
• Coherent detection & advanced modulation
Summary
Potential future aspirations
• PAM for 500m
• 3D packaging for C2C
Confidential and 2

3. At @ Luxtera:
Si photonics integration
Confidential and 3

4. Si optical chips and interconnect systems
Optical Filters - DWDM
Flip-chip bonded lasers
10G Modulators
4 km
10G Rx
Fiber cable Ge detectors, TIAs
Ceramic Package
copper SOI transistor Optical “wire” SOI transistor
(waveguide)
poly Si
WG
Field oxide "Active" Si Si
Buried Oxide (BOX)
"Handle" Si
Confidential and 4

5. Design experience
Grating couplers
Designed SOI production wafer
structure
• Integration challenge
• Need best system compromise of
performances of individual
components
“Photonics Spectra”, March 2006
– Grating couplers (IL and
bandwidth)
– Waveguide loss
– Modulators (speed and IL)
– AWG (cross-talk and IL)
– Manufacturability and yield
Confidential and 5

6. General rigorous device design methodology
Functionality
Architectural choices
Design inputs and outputs
• Input parameters interactions
Theoretical limits
Key trade-offs
Design:
• theory
• modeling & simulations
• experimental DOEs (tape-outs)
Design and process sensitivities
• corner cases, Monte-Carlo statistics
• manufacturability, yields
Skewing test results
• Repeatability, reproducibility, accuracy, Gage R&R
Correlations and building models
Confidential and 6

7. Wafer level testing: Design and architecture
Million of multi-port devices on ea.
wafer
fibers
RF • 6D alignment
Multiple input-output fibers
• separated by only 127um
DC Finds ea. device in seconds
• not minutes
Initial aligning structures:
• one-port reflecting Littrow gratings
Capacitor Z-axis spacing sensor
• tight 5um air gap across 8” wafer
Operator-free 24/7
Still in production (10 years)
• 9 patents
8” Si wafer “Photonics Spectra”, March 2006
Confidential and 7

8. At @ Infinera:
InP photonics integration
Confidential and 8

9. 10ch. x 10G OOK Tx and Rx PICs
Optics and Photonics News (2009) CS MANTECH Conference (2006)
Confidential and 9

10. 10ch. x 10G OOK Transmitter module
200G spacing
0
Normalized Power (dB)
-10
-20
-30
-40
-50
Tx PIC -60
1.525 1.530 1.535 1.540 1.545
Wavelength (µm)
Fiber Systems, Lightwave Europe (2006)
OPN (2009)
Confidential and 10

11. Advanced modulation formats
Confidential and 11

12. Pol-Mux DQPSK Reference Tx box: Performance
HW development and integration
Amplitude
• Ref Tx to Ref Rx: test data shown
• OSNR-loaded long-term (24/7) stability <0.1dB Q
Phase
90o 0o
TE
180o 270o
TM
Confidential and 12

13. Reference Tx for PM-DQPSK and coherent QPSK
(typical HW configuration)
Confidential and 13

14. Typical test set for BER test (simplified)
OFC 2011 (OML7)
Confidential and 14

15. Non-coherent DQPSK Rx
Passive PIC: uses 1-bit delay
Pros:
• No LO frequency mismatch || Pol. demux done by MIMO analog control
• No need for coherent DSP ASIC || Saves 1-2 yrs development time || Saves power
Cons:
• Reduced Rx power sensitivity
• TE/TM paths must be bit aligned – need integrated PBS and pol. rotator → High losses in InP
• MIMO circuits’ zero offsets complicate pol. tracking || Reduced Q performance
MIMO ASIC
1-bit delay
OFC 2011 (OML7)
Confidential and 15

16. Coherent Rx
Active Rx PIC: uses DFB LO
Pros:
• Pol. tracking done by DSP ASIC digitally
• DSP compensates for PMD, CD
• PBS can be external
• Better Rx power sensitivity
Cons:
• Requires development time of complex, power-hungry DSP
• Tx DFB and LO DFB must have limited linewidth, phase noise
“10-channel, 28 Gbaud PM-QPSK, monolithic InP Terabit Superchannel Receiver PIC”
M. Kato, R. Malendevich, D. Lambert et al., 2011 IEEE Photonics invited, & OFC 2011, invited
Confidential and 16

17. 1 Tb/s Tx PIC
Each PIC:
>400 integrated functions
Each λ:
“Terabit Superchannel Coherent InP PM-QPSK Transmitter PIC”
P. Evans, M. Fisher, R. Malendevich et al., Opt. Express 19 2011 & OFC 2011 (post-deadline)
Confidential and 17

18. InP DQPSK modulator
“Terabit Superchannel Coherent InP PM-QPSK Transmitter PIC”
P. Evans, M. Fisher, R. Malendevich et al., Opt. Express 19 2011 & OFC 2011 (post-deadline)
Confidential and 18

19. Tx DFB Frequency Noise Power Spectral Density (PSD)
Fundamental problem: phase noise σ = 2π ⋅ LW ⋅ ∆t
Linewidth < 1MHz
Linewidth < 1MHz
Ref. on slide 18
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20. First live network coherent PIC demo (2010)
Confidential and 20

21. et al.
Linear Tx driver
From coherent DSP
Confidential and 21

22. *
et al.
* O. Gerstel (VZ) et al, “Elastic Optical Networking: A New Dawn for the Optical Layer?”, IEEE Comm. Magazine, 2012
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23. Gridless super-channel transmission
Same ref. as on slide 23
Confidential and 23

24. “Elastic optical network”
(spectrum defragmentation)
Same ref. as on slide 23
Confidential and 24

25. Potential future aspirations
Confidential and 25

26. PAM for 500m
Ref.: IEEE 100G taskforce
Confidential and 26

27. 3D Packaging for C2C
Ref.: Computer Systems Based on Silicon Photonic Interconnects,
Sun, IEEE Proceedings (2009) Confidential and 27

28. Summary
The field of photonics integration is blossoming
• With applications in long-haul, metro, local, FTTH and datacenter
networks, as well as C2C and MCM communication
– Even in your living room!
• A number of start-ups (Aurrion, Skorpio Technologies, Luxtera) and
giants (Intel, Huawei, Cisco/Lightwire, Oracle/Sun, IBM, Finisar,
Samsung) intensifying the field
• The future of photonic integration looks as promising as ever
• I have personally worked on OOK and coherent PICs, modules and
systems, integrated both in Si and InP
– From concept to real world, customer demos and production
Confidential and 28

29. Addendums
Confidential and 29

30. Academics
CREOL (Center for Research and Education in Optics &
Lasers) Univ. of Central Florida
Kiev National University
• 1st runner-up National Physics Olympics
Confidential and 30