marching towards a fully-integrated dwdm link for hpcs
TRANSCRIPT
Marching towards a fully-integrated DWDM link for HPCs through ULTRALIT program
Di Liang Sr. Research Scientist, PI Large-Scale Integration Photonics (LSIP) Lab Hewlett Packard Labs
ARPA-E ENLITENED Phase 2 Kickoff Jan. 13 & 15, 2021
D. Liang @ ARPA-E ENLITENED Phase 2 Kickoff, 2020 Photonic Interconnected Exascale
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racks can behave as a single server
100’s
Reduces energy
to move data
Reduces cost to move data
High-radix topologies
become possible
Optimizes bandwidth per
pin
D. Liang @ ARPA-E ENLITENED Phase 2 Kickoff, 2020 HPE DWDM Photonics 2.0 - ULTRALIT (kickoff on 04/14/20)
ULTRA-ENERGY-EFFICIENT INTEGRATED DWDM OPTICAL INTERCONNECT (ULTRALIT)
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– Goal: A fully-integrated DWDM optical transceiver solution on silicon with over 1 Tb/s data rate and <1.5 pJ/bit energy efficiency at 50 oC (proposal goal)
Differential technical concepts: – DWDM+SDM with single QD source
– NRZ medium-BW modulation/λ
– Integrated III-V/oxide/Si MOS capacitor – Athermal & efficient channel control
(laser, modulator, deinterleaver, DEMUX) – Efficient NRZ modulation
– Ge and III-V co-integration on Si
– Multiple source and detector flavors – Monolithic, heterogeneous and a combined version – SiGe and QD avalanche photodetectors
Or wavelength deinterleaver [UCSB]
D. Liang @ ARPA-E ENLITENED Phase 2 Kickoff, 2020 DWDM TRx system energy efficiency evaluation
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– 10/20λ-source with 60/30 GHz ch. spacing – 10 modulator/bank with 60 GHz ch. spacing – 40 ch. x 25 Gb/s (NRZ) = 1 Tb/s/chip – Goal: on(off)-chip comb laser WPE: >5%(10%)
SOA WPE: >10%(20%) <1 pJ/bit energy efficiency for both on- and off-chip
comb source configurations
D. Liang @ ARPA-E ENLITENED Phase 2 Kickoff, 2020 Multi-wavelength source development
Heterogeneous QD comb lasers on silicon (HPE)
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– Low-threshold operation (min Jth=163 mA/cm2)
– Flexible 15-100 GHz channel spacing design
– Record-large comb width: 3 dB: 12 nm; 6 dB: 18 nm; 10 dB: 25 nm
25 nm
>220λ, ∆λ=15.5 GHz
Kurczveil, FiO+LS FTu6E.6 (2020)
1x2 MMI 2x2
MMI Grating Coupler
Lcavity = 2.6 mm (FSR: 15.5 GHz)
SOA SOA SA
Lext = 780 µm
R=50%
R=100% LSOA = 1200 µm LSA = 176 µm
10 dB
D. Liang @ ARPA-E ENLITENED Phase 2 Kickoff, 2020 Multi-wavelength source development
Monolithic QD modelocked lasers and amplifiers on silicon (UCSB)
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SOA
MLL
0 100 200 300 400 5000
5
10
15
20
Pow
er (m
W)
Current (mA)
SA section floatingRoom temperature
Wavelength (nm)
Pow
er (d
Bm)
18λ, 60 GHz, Max. WPE: 10%
MLL
SOA
D. Liang @ ARPA-E ENLITENED Phase 2 Kickoff, 2020 High-speed modulator development
Heterogeneous MOS capacitor microring modulators (built on the same chip with lasers)
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R=10 µm R=20 µm
R=10 µm, ER=5.6 dB
R=20 µm, ER=7.9 dB
28 Gb/s
RC-limited BW
Reference Type Mod. Rate (Gb/s) ER (dB) VπL
(V-cm) IL (dB)
Webster, OFC (2015) S-MZI 40 8 NA NA
Hiraki, Nat. Photon. 11, 482 (2017) H-MZI 32* 3.1 0.09 1
Thiessen, Opt. Expr. 27, 102 (2019) H-MZI 25 2.3 1 0.5
This work H-Ring 28 5.6 1 0.5
Sirinivasan, ECOC (2020)
S: silicon, H: heterogeneous * pre-emphasis drive signal
D. Liang @ ARPA-E ENLITENED Phase 2 Kickoff, 2020 Highly sensitive APD development
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SiGe APD Heterogeneous QD APD (laser epi)
20 Gb/s, 17.1 V
20 oC, 15 Gb/s (17 V)
D. Liang @ ARPA-E ENLITENED Phase 2 Kickoff, 2020 Preliminary link testing I (confidential)
Heterogeneous comb laser LiNbO3 modulator commercial InGaAs Rx
– 28-ch., 60-GHz comb laser
– External modulation up to 32 Gb/s limited by the pattern generator
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D. Liang @ ARPA-E ENLITENED Phase 2 Kickoff, 2020 Preliminary link testing II (confidential)
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– All discrete lasers, modulators and detectors are fabricated in the same process
– 11-ch. comb laser MOSCAP modulator
– MOSCAP modulator heterogeneous QD APD
– I/O loss (6.5-10 dB/GC) and insertion loss from tunable filter (5 dB) huge link budget (≥ 28 dB for Tx, ≥38 dB for TRx)
– 2 optical amplifiers contribute too much noise
– Full TRx link test is on-going with SiGe APD
D. Liang @ ARPA-E ENLITENED Phase 2 Kickoff, 2020 Advanced integration platform development (confidential)
Direct epitaxy on a bonded III-V-on-silicon template
– Decouple intertwined mismatches in lattice, polarity and thermal expansion in heteroepitaxy.
– Enable seamless integration with SiPh PIC
– Potential appreciable cost saving by 300 mm-scale epitaxy and multiple regrowths
– Promising experimental results: – Record-low threading dislocation density of III-V epitaxy
on Si – Record-narrow PL FWHM on both III-V and Si substrate
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D. Liang @ ARPA-E ENLITENED Phase 2 Kickoff, 2020 Bonus outcome, I
Widely tunable, narrow-Dl heterogeneous QD lasers
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Tran, APL Photonics (2020) Heterogeneous QD
Guo, CLEO PDP (2020) Malik, Photon. Research 8, 1551-1557 (2020) [Editor Pick]
52 nm (48-58 dB) ∆λ=5.3 kHz (10X improvement)
( )3
21spH
E
h nPQ Q
π νν α∆ = +
D. Liang @ ARPA-E ENLITENED Phase 2 Kickoff, 2020 Bonus outcome, II
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High-performance monolithic and heterogeneous DFB lasers
M: monolithic, H: heterogeneous
P1
N
P2
Vmos:-6:1:6 V
Wan, LPR 14, 2000037 (2020) Liang, IPC (postdeadline) (2020)
D. Liang @ ARPA-E ENLITENED Phase 2 Kickoff, 2020 Program execution status
– Covid-19 impact: – Hiring freeze (postdoc, intern) – Comb laser and SiGe APD fab – Laser and SOA testing
– Risk mitigation: – Combined designs to minimize
fab runs – Relocated testing facility
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D. Liang @ ARPA-E ENLITENED Phase 2 Kickoff, 2020 Publication list
– Journal: 1. D. Liang, A. Descos, S. Srinivasan, C. Zhang, G. Kurczveil, Z. Huang, and R. Beausoleil, "High-Performance 1310 nm Quantum-Dot Distributed Feedback Laser with
Integrated Capacitive Control," Optica, 2021 (submitted). 2. Y. Wan, C. Xiang, J. Guo, R. Koscica, M. Kennedy, J. Selvidge, Z. Zhang, L. Chang, W. Xie, D. Huang, A. C. Gossard, and J. E. Bowers, "High speed evanescent quantum-dot
lasers on Si," Light: Science and Applications, 2021 (submitted). 3. A. Malik, J. Guo, M. A. Tran, G. Kurczveil, D. Liang, and J. E. Bowers, "Widely tunable, heterogeneously integrated quantum dot O-band lasers on silicon," Photonics Research
(Editor Pick), vol. 8, pp. 1551-1557, 2020. 4. Y. Wan, J. C. Norman, Y. Tong, M. J. Kennedy, W. He, J. Selvidge, C. Shang, M. Dumont, A. Malik, H. K. Tsang, A. C. Gossard, and J. E. Bowers, "1.3 µm Quantum Dot-
Distributed Feedback Lasers Directly Grown on (001) Si," Laser & Photonics Reviews, vol. 14, p. 2000037, 2020. 5. B. Tossoun, G. Kurczveil, Y. Yuan, A. Jones, C. Zhang, A. Descos, Z. Huang, A. Beling, J. C. Campbell, D. Liang, and R. G. Beausoleil, "InAs quantum dot waveguide
photodiodes heterogeneously integrated on silicon," Optica, vol. 6, pp. 1277-1281, 2019 – Conference: 1. Y. Wan, C. Xiang, R. Koscica, M. Kennedy, J. Guo, Z. Zhang, L. Chang, W. Xie, D. Huang, A. C. Gossard, and J. E. Bowers, "High speed evanescent quantum-dot lasers on
Si," in OFC, 2021 (submitted). 2. Y. Wan, J. Norman, Y. Tong, M. Kennedy, C. Shang, J. Selvidge, H. K. Tsang, A. C. Gossard, and J. E. Bowers, "1.3 µm regrown quantum-dot distributed feedback lasers on
(001) Si: a pathway to scale towards 1 Tbit/s " in CLEO, 2021 (submitted). 3. S. Srinivasan, D. Liang, and R. G. Beausoleil, "Heterogeneous SISCAP Microring Modulator for High-Speed Optical Communication," in ECOC Virtual, 2020, pp. paper Tu1B-7. 4. D. Liang, A. Descos, C. Zhang, G. Kurczveil, Z. Huang, and R. Beausoleil, "A Heterogeneous O-Band Quantum-Dot DFB Laser with Integrated MOS Capacitive Control " in
IEEE Photonics Conference (postdeadline) Virtual Conference, 2020. 5. B. Tossoun, S. Srinivasan, A. Descos, G. Kurczveil, D. Liang, and R. Beausoleil, "High-Speed III-V on Si Quantum Dot Avalanche Photodiodes with Polarization Dependent
Gain " in IEEE Photonics Conference Virtual Conference, 2020, p. ThE1.2. 6. S. Srinivasan, B. Tossoun, G. Kurczveil, Z. Huang, D. Liang, and R. Beausoleil, "160Gb/s optical link using Quantum-Dot comb laser source and SiGe APD," in IEEE
Photonics Conference Virtual Conference, 2020, p. MH1.2 7. J. Guo, A. Malik, M. A. Tran, G. Kurczveil, D. Liang, and J. E. Bowers, "Widely Tunable, Narrow Linewidth Quantum Dot Lasers heterogeneously Integrated on Silicon," in
CLEO (postdeadline) San Jose, CA, USA, 2020. 8. D. Liang, G. Kurczveil, Z. Huang, B. Wang, A. Descos, S. Srinivasan, Y. Hu, W. V. Sorin, S. Cheung, S. Liu, P. Sun, T. V. Vaerenbergh, M. Fiorentino, J. E. Bowers, and R. G.
Beausoleil, “Green Integrated DWDM Photonics for Next-gen High-performance Computing,” in OFC San Diego, CA, USA, 2020. – 3 patents 15