1. 先端超高周波情報工学 ( 博士後期課程 ) 先端超高速情報工学 ( 留学生特別コース） Advanced High-Speed Communication Engineering Hirohito Yamada Optical devices and integrated optical circuits for photonic network applications Lecture on July 2, 2015

2. Self-intoroduction Hirohito Yamada 1987Graduated from Dep. of Electronics, Graduate School of Eng.,Tohoku Univ. Doctor Engineering in study of surface emitting laser diodes 1987 – 1997 Research Laboratories, NEC Corp. Research and development of laser diodes for optical communications 1997 – 1998 Physical Sciences, NEC Research Institute, Inc., Princeton, NJ Research of wavelength tunable lasers with photorefractive materials 1998 – 2006 Research Laboratories, NEC Corp. Research of photonic crystal and Si-wire waveguide devices 2006 –Graduate School of Engineering, Tohoku University Education in Department of Communications Engineering Research of Si photonic devices for optical communications

3. Lecture contents Purpose of this lecture: - To understand background of requiring photonic networks - To study about future photonic network systems - To study about optical devices and integrated optical circuits Lecture contents: - Background of requiring high capacity optical network - Photonic network and photonic node - Optical devices and integrated optical circuits for photonic network Lecture slide can be downloaded from: http://www5a.biglobe.ne.jp/~babe Any questions: E-mail: yamada@ecei.tohoku.ac.jp

4. Background of requiring high-speed network

5. Optical fiber submarine networks Cited from https://www.alcatel-lucent.com/solutions/submarine-networks

6. Spreading application range of optical communication Storage Area Network(SAN) with Active Optical Cable(AOC) Bus interface for the SONY VAIO ZBackplane of a server Universal Bus Interface for PC Light Peak

7. Growth of internet traffic in Japan year 2005200620072008200920102011200420132012 Cited from: H26 年度版情報通信白書 Total download traffic in Japan Total upload traffic in Japan Daily average value Total download traffic in Japan was about 2.6T bps at the end of 2013 Annual growth rate: 30%

8. Power consumption forecast of network equipments Domestic internet traffic is increasing 40%/year If increasing trend continue, by 2024, power consumption of ICT equipments will exceed total power generation at 2007 http://www.aist-victories.org/jp/about/outline.html Annual power consumption of network equipments ( ×10 11 Wh) year Total internet traffic (Tbps) Network traffic Total power generation at 2007 Power consumption

9. Spreading application range of optical communication Rack to rack → Board to board → Chip to chip → On chip interconnection Cited from: C. Gunn, “CMOS Photonics™ Technology Enabling Optical Interconnects” Luxtera, Inc. Light Peak Infiniband DDR(20Gbps)AWG24 Up to 20m Active optical cable (AOC) Up to 100m

10. Optical module for board-to-board optical link 10Gbps, 12ch(120Gbps) Parallel optical module MicroPOD TM made by Avago IBM Power775 super computer System board of Power775

11. On chip optical interconnection for LSI Global interconnection Local interconnection Transistor layer - High speed - Low power consumption - Low noise Optical interconnection Cross-section of LSI chip (Intel) 130nm 6-layer cupper wire - Clock frequency - Power consumption - Noise problem Emerging performance limit of LSI Performance limit of electrical interconnection Many core architecture Optical interconnection Electrical interconnection

12. Signal transmission capacity Question: How much information can be transmitted by a thin piece of optical fiber ? - Apple Next Gen. Thunderbolt: 20G bps Hint: - FTTH (NTT FLETS ・光 Premium, KDDI au 光 ): 1G bps A. 100G bps (1G = 10 9 ) B. 10T bps (1T = 10 12 ) C. 1P bps (1P = 10 15 )

13. Multiplexing in telecommunications t1t1 t3t3 t2t2 Bandwidth of transmission line f1f1 Signal bandwidth f2f2 f3f3 f4f4 frequency t t1t1 t2t2 t3t3 1 msec Time-division multiplexing (TDM) Frequency-division multiplexing (FDM) Single transmission line

14. Multiplexing in optical communications Electrical multiplexing - Electrical time-division multiplexing (ETDM) - Electrical frequency-division multiplexing (EFDM) Up to 100G bps, limited by response speed of electronics time (frequency) Ch1Ch2Ch3 Light Source Photo Detector/ Demodulator Optical Modulator Optical fiber 40G bps bps: bit per second 1G bps 100M bps 64k bps 100M bps 1G bps 40G bps ETDM or EFDM DemultiplexerMultiplexer Optical Electrical

15. Optical Modulation Direct modulation of laser diode Optical modulator - Electro-absorption (EA) optical modulator - LiNbO 3 (LN) MZI optical modulator L-I characteristics of laser diode Optical signal Electrical signal Current 40G bps EA modulator (OKI) LN optical modulator (Sumitomo Osaka Cement) Light output

16. Developing history of optical-link capacity Developing history of optical-link capacity in Japan 1 st generation with ETDM, EFDM (Electrical method)

17. Multiplexing method of 1 st and 2 nd generations Electrical multiplexing - Electrical time-division multiplexing (ETDM) - Electrical frequency-division multiplexing (EFDM) Up to 100Gbps, limited by response speed of electronics Optical multiplexing - Wavelength division multiplexing (WDM) More than 10T bps transmission (40G bps×273 wave ＝ 10.9T bps, 117km) have been demonstrated in 2001 Using many different wavelength as different channel λ1λ1 λ2λ2 λ3λ3 λ4λ4 λ5λ5 λ6λ6 λ7λ7 λ1λ1 λ2λ2 λ3λ3 λ4λ4 λ5λ5 λ6λ6 λ7λ7 WDM transmission (1 st generation) (2 nd generation) time (frequency) Ch1Ch2Ch3 - Optical time-division multiplexing (OTDM) Bandwidth of silica optical fiber C-bandL-band 1460nm1530nm1565nm1625nm S-band ~21 THz

18. WDM transmission with single fiber LaserPD DEMOD 40G bps MOD Laser MODPD DEMOD MOD Wavelength Multiplexer Wavelength Demultiplexer Single fiber 40G bps λ1λ1 λ2λ2 λ3λ3 λ1λ1 λ2λ2 λ3λ3 120G bps 40G bps Electrical Multiplexing Electrical Demltiplexing

19. Developing history of optical-link capacity 2 nd generation using WDM and Optical Amp. (Optical method) F-6M WDM System WDM + ETDM OTDM WDM + OTDM 1.6T (40G × 40) 3 rd

20. Multiplexing method of 3 rd generations Coherent transmission ‥‥ modulating both amplitude and phase of lightwave Optical orthogonal detection, Optical heterodyne/homodyne detection Digital coherent optical transmission Multilevel modulation ‥‥ QAM, DPSK/DQPSK/DP-QPSK etc. Digital signal processing (DSP) ‥‥ Error correction code (FEC) Electrical Code-division multiplexing (CDM) (3 rd generation)

21. Increasing transmission capacity of optical link 19801990200020102020 year 100T 10T 1T 100G 10G 1G 100M 1P Transmission capacity per single fiber (bps) Electrical Mux.(Laboratory) Electrical Mux.(Commercial) Optical Mux.(Laboratory) Optical Mux.(Commercial) ETDM EFDM 1 st Gen.2 nd Gen.3 rd Gen. WDM OTDM Multilevel Modulation Digital coherent What technology drive next gen. ?

22. Multiplexing method of 4 th generations 1. SDM using an optical fiber with multi-core Space-division multiplexing (SDM) 1.01P bps (380G bps×222 wavelength×12 core) 52.4 km transmission with multi-core fiber (NTT, Fujikura Ltd, Hokkaido Univ. and Technical University of Denmark reported in ECOC2012) (4 th generation) Optical Cross section of 19 core fiber (Furukawa Electric Co., Ltd) core Ch1 SDM transmission with a multi-core fiber Ch2 Ch3 Ch4 Ch1 Ch2 Ch3 Ch4 core 125 μm Conventional single-core fiber 125 μm core clad

23. Multiplexing method of 4 th generations Space-division multiplexing (SDM)(4 th generation) Optical 2. SDM using spatial modes with a multi-mode fiber Mode1 Mode2 Mode3 Mode4 Mode5 SDM transmission with a multi-mode fiber Propagating modes in a multimode fiber LP 01 modeLP 11 modeLP 02 mode LP 21 modeLP 31 mode Each spatial mode transmit different signal as different channel

24. Multiplexing method of 4 th generations 3. Multi-input/multi-output (MIMO) transmission with a multi-mode fiber Tx1 Tx2 Tx3 Rx1 Rx2 Rx3 MIMO transmission for wireless systems “ Space” is the final frontier of optical communication Rx1 Rx2 Rx3 Tx1 Tx2 Tx3

25. Increasing transmission capacity of optical link 19801990200020102020 year 100T 10T 1T 100G 10G 1G 100M 1P 305T (19 core) 109T (7 core) 1.6T Transmission capacity per single fiber (bps) Electrical Mux.(Laboratory) Electrical Mux.(Commercial) Optical Mux.(Laboratory) Optical Mux.(Commercial) ETDM EFDM 1 st Gen.2 nd Gen.3 rd Gen. 4 th Gen. WDM OTDM Multilevel Modulation Digital coherent Multicore fiber 1P (12 core) Total network traffic in Japan 2.6T (2013) +40%/year

26. Needs for developing new technology Fan-in/Fan-out for multi-core fiber Compact fan-in/fan-out Masaki Nara, “Vertical Coupling Optical Interface for Single Lithography Silicon Photonics”

27. Needs for developing new technology Connector for multi-core fiber Optical amplifier for multi-core fiber Spatial-mode converter for multi-mode fiber New studies are starting to explore the small “space” Furukawa Electric Co, Ltd Sumitomo Electric Industries, Ltd Kyushu Univ.

28. Optical network Photo diode Optical signal Electrical signal Laser diode Laser diode Header analysys Optical devices Electron devices Optical modulator Optical modulator Laser diode Optical modulator Electronic switch Label detection Optical(O) – Electrical(E) – Optical(O) Buffer memory Optical link (optical fiber) node (router) node (router) Construction of router

29. Switching method Circuit switching Packet switching ex) telephone ex) data communication, Internet Circuit switch One line is exclusively used by end-to-end One line is shared by all user Packet switch LabelData

30. Packet switching Each packet has a label which inform destination address of data Packet switch labelPort Routing table ① ① ② ③ ④ ⑤ ⑥ 1 2 3 4 1 2 3 4 ② ③ ④ ⑤ ⑥ 4 4 1 2 3 4 labelPort Routing table ① 1 1 1 2 ② ③ ④ ⑤ ⑥ 3 4 Packet switch outputs packet at any port based on routing table Every data is divided by a unit of packet Routing table is made by the address information of each packet

31. Processing speed bottleneck in each node Optical link (optical fiber) node (router) node (router) Tollgate Expressway Link capacity: 10Tbps (40Gbps × 256 wave WDM) Processing speed: 100Gbps Traffic jam

32. Resolving bottleneck by photonic network node (router) ETC system Optical link (optical fiber) node (router) Link capacity: 10Tbps (40Gbps × 256 wave WDM) Processing speed: 100Gbps Expressway

33. What is photonic network Next generation network routing optical signal without OE/EO conversion (OE/EO: optical → electrical / electrical → optical) OPS router Mesh-type NW OPS router OADM(Optical Add/Drop Multiplexer) WDM ring NW OADM OXC WDM ring NW OADM OBS(Optical Burst Switching) OXC(Optical cross connect) WDM ring-type network WDM mesh-type network OPS(Optical Packet Switching) Photonic MPLS(Multi-Protocol Label Switching)

34. Wavelength Router 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 DEMUXMUX DEMUX Port 1 Port 2 Port 3 Port 4 Port 5 Port 6 Port 7 Port 8 Output port can be switched by changing wavelength 1 1 3 3 MUX

35. Arrayed waveguide grating(AWG) 50 mm Arrayed Waveguide Grating (AWG) SiO 2 core SiO 2 clad Si substrate 0.5  m Made of silica waveguide N × N wavelength router can be constructed by an N × N AWG AWG made by Si-wire waveguide 50  m Size 1/1000 λ 1, λ 2, λ 3, …, λ N λ 2, λ 3, λ 4, …, λ 1 λ 3, λ 4, λ 5, …, λ 2 λ N, λ 1, λ 2, …, λ N-1 Extremely small AWG can be realized by Si-wire waveguide

36. Thermo-optic switch with Si-wire waveguide T. Chu et al., Optics Express 13, 10109 (2005) Electrode Microheaters Si-wire waveguide Switching characteristics T. Chu et al., Proc. SPIE 6477 (2007) Photograph of the 1×8 switch Footprint size: 4 mm×2 mm Port1 Port2 Port8

37. Optical Add/Drop Multiplexer(OADM) R-OADM (Reconfigurable OADM) Certain wavelength signal can be dropped out or added in OADM 1 ‥‥ n i i WDM signal Add/Drop wavelength can be settable OADM 1 ‥‥ n i i WDM signal OADM WDM ring NW OADM WDM ring NW OADM

38. R-OADM made of Si-wire waveguide - Wavelength tuning by T-O effect - Wavelength tuning range: 6.6 nm - Channel switching time: < 100 μsec Wavelength tuning characteristicsDemultiplexing characteristics T. Chu et al., IEEE Photon. Technol. Lett. 18, 1409 (2006)

39. Tunable wavelength laser Tunable laser with ring resonator

40. Function and construction of OPS node Routing control ‥‥ Producing routing table Label processing ‥‥ Reading label information and deciding output port based on routing table Switching ‥‥ Switching output port of packet Packet Scheduling ‥ ‥ Controlling output timing to avoid packet collision Buffering ‥‥ Keeping data waiting a while for the timing of output DateLabel Routing (Producing routing table) Label processing (Deciding output port) Switching (Switching output port) Scheduling (Packet collision control) Buffering (waiting data output) Output

41. Optical label processing t Data Color label 1 2 3 4 2 4 3 1 1 4 3 2 Optical fiber grating t Data Matching of label and grating pattern Circulator Missmatching

42. Optical Buffer 1. Based on Optical Delay Line and Optical Switch 2. Based on Slow Light Electromagnetically Induced Transparency(EIT) 300,000km/s → 28m/s 0.9μK(-273 ℃ ) Natrium (Na) 70 ～ 90K(-203 ～ -183 ℃ ) Rubidium (Rb) 300,000km/s → 1km/s optical switch optical delay line |1> |3> |2> coupling probe probe frequency absorption transmittance

43. Integrated Optical Circuit Integrating various micro photonic devices Photonic Network Photonic node Integrated optical circuit Optical switchSi waveguideMUX/DEMUX Micro photonic devices for optical network Photonic network Resonator

44. Reporting Assignment Describe your idea of the future network which can solve problems of explosion of network traffic, and what can we do for enjoying comfortable and ecological network life. Format: Word or PDF File Submission to yamada@ecei.tohoku.ac.jp Deadline: 3 rd August

45. Moore's Law Predicted by Gordon Moore (One of founders of Intel corp.) in 1965 Observation based on the history of computing hardware, the number of transistors on integrated circuits doubles every two years (Performance of electronics doubles every 18 months) Evolution of Intel CPU Collapse of Moore’s Law Core 2 Duo Core i7