Large scale optical circuit switches for future data center applications ONDM2017 workshop Yojiro Moriand Ken-ichi Sato
Outline 1. Introduction -Optical circuit switch for datacenter- 2. Sub-switch configuration 3. Large-scale optical switch Ø based on tunable laser Ø based on tunable filter 4. Summary 1
Datacenter Flow Small flow Large flow Mail Search Datacenter flow= Mice flow + Elephant flow 2
Hybrid Network Architecture Electrical packet switch network Mice flows are processed by electrical packet switches Requirements Internet Intra-datacenter network 1. Large port count for supporting Electrical many ToR packet switches 2. High speed switching to reduce latency switches 3. Low cost Mice flow Elephant flow Optical circuit switch network Elephant flows are processed by an optical circuit switch Optical circuit switch 3
Large-scale optical circuit switch Space switch Wavelength-routing switch Pros: Wavelength independency Pros: Cost effectiveness Cons: Complexity (Port count) 2 Cons: Bandwidth limitation Combination of space switch and wavelength-routing switch 4
Outline 1. Introduction -Optical circuit switch for datacenter- 2. Sub-switch configuration 3. Large-scale optical switch Ø based on tunable laser Ø based on tunable filter 4. Summary 5
Space Switch MxM DC switch & Multicast switch 1xM MZI switch Mach-Zehnder Interferometer (MZI) out 1 out 2 1xM switch Mx1 coupler in out M-1 out M DC: Delivery and coupling 6
Wavelength-routing Switch NxN wavelength-routing switch based on tunable laser NxN wavelength-routing switch based on tunable filter #1 #2 λ1 λ2 LD #1 LD #2 Nx1 AWG #1 #2 λn λ1 #N Wavelength-tunable laser Nx1 coupler EDFA λn Wavelength-fixed filter (1xN AWG) LD #N Fixed-wavelength laser EDFA #N λ2 Wavelength-tunable filter 7
Outline 1. Introduction -Optical circuit switch for datacenter- 2. Sub-switch configuration 3. Large-scale optical switch Ø based on tunable laser Ø based on tunable filter 4. Summary 8
Switch based on Tunable Laser MN N MxM DC switch Wavelength-tunable transmitter Fiber connection Nx1 coupler M NxN WR switch EDFA λ1 λ2 λn λ1 λ2 λn λ1 λ2 λn λ1 λ2 λn 1xN AWG Wavelength-fixed filter Tunable laser MxM DC switch EDFA 1xN AWG Total # MN N M M Per-port 1 1/M 1/N 1/N MN 9
Experimental Demonstration [OECC2016] 1,440x1,440 optical switch Ø DC-switch scale is 8 Ø # of wavelengths is 180 (on 25-GHz grid) 10Gbps intensity-modulated signals Tunable laser (target) 180 CW sources Synchronous controller Intensity modulator 2-ch pattern generator Intensity modulator (non -target) Crosstalk source Power controller WSS P in DC switch Aggregation&Amplification WR switch 8x1 256x1 25.7dB Odd coupler coupler 25/50GHz interleaver EDFA 1.5dB Even (30dB gain) 4dB 1x8 switch 11.6dB 179 (static) or 178 (dynamic) wavelengths Monolithic twin 1x90 AWGs BERT Structure of fast-tunable laser (Collaboration with AIST) PLC-based AWG (Collaboration with NTT Electronics) PLC chip 36.4x44.0 mm 2 Module box 120x70x7 mm 3 10
Switching Time [OECC2016] Edge wavelength (a) Adjacent wavelength (b) Center wavelength (c) Edge wavelength log 10 (BER) in 10 4 bits λ1 0-1 -2-3 -4 λ2 λ1 λ2 λ1 λ91 λ2 λ1 λ91 λ1 (a) (b) (c) λ1 λ180 λ180 λ1 498 µs 498 µs 498 µs FEC threshold λ91 (a) (b) (c) Time (100µs/div) λ180 Good transmission characteristic with <500μs switching time 11
Outline 1. Introduction -Optical circuit switch for datacenter- 2. Sub-switch configuration 3. Large-scale optical switch Ø based on tunable laser Ø based on tunable filter 4. Summary 12
Switch based on Tunable Filter N Aggregation and distribution part LD1 LDN Nx1 AWG EDFA 1xN splitter N MxM multicast switch M MN LD1 LDN MN LD1 LDN Wavelength-fixed laser Wavelength-tunable filter Silicon photonics technologies Fixed laser Nx1 AWG EDFA MxM multicast switch Tunable filter Total # MN M M N MN Per-port 1 1/N 1/N 1/M 1 13
Silicon-Photonic Switch Components [ECOC2016] Fabricated 8x8 MC/DC switch (collaboration with AIST) 12mm (collaboration with NEC) Fabricated tunable filter switch 14 mm (a) chip (b) module (c) measured switching time Total loss: 16 db On-chip loss: 4 db Yojiro MORI, Nagoya University (a) chip (b) module (c) measured switching time Total loss: 18 db On-chip loss: 4 db 14
Proof-of-Concept Experiment [ECOC2016] Adjacent channels as Inter -band crosstalk source 2x1 coupler EDFAs LD Mod. EDFA VOA Fiberdelay LD PPG 25GHz/50GHz spacing adjacent channels Mod. Target channel: 1546.52nm LD IM 10-Gbps intensity modulation 2x8 coupler Intra-band crosstalk VOAs 8x8 multicast switch DUT VOA 2x1 coupler Rx OSA Pre amp. Log 10 BER 0-1 -2-3 -4-5 -6-7 -8 Tunable filter (25-GHz grid) 1ch 1ch w/o w/o intra intra 1ch 1ch w/ w/ intra intra 50G 3ch w/o 50G intra w/o intra 50G 3ch w/ 50G intraw/ intra 25G 3ch w/o 25G intra w/o intra 25G 3ch w/ 25G intraw/ intra Inter-band crosstalk with both 50GHz and 25GHz spacing -9-38 -37-36 -35-34 -33-32 Received channel Power P in [dbm] 15
Outline 1. Introduction -Optical circuit switch for datacenter- 2. Sub-switch configuration 3. Large-scale optical switch Ø based on tunable laser Ø based on tunable filter 4. Summary 16
Summary l We introduced large-scale optical circuit switches for future intra-datacenter applications. l The large-scale switch can be attained with a combination of space switches and wavelengthrouting switches. l We demonstrated optical switches based on tunable laser or tunable filter. l Considering the switching time, tunable-filter-based switch may be suitable for future applications. Thank you for you kind attention 17