LCOS Gridless Wavelength Selective Switch Based on LCOS Technology Yasuki SAKURAI To meet ever-increasing demand for network capacity, both the spectral e ciency and symbol rate carried by a single channel have been increasing dramatically. As a promising candidate, elastic optical path networks have been proposed as a spectrally e cient networking technology, which e ectively supports per-channel variable tra c demands. The elastic optical networks allow us to deal with the mix of various tra cs with arbitrarily variable symbol rates and modulation formats, which are not only 10 Gbps legacy channels but also core tra c channels over 400 Gbps. In such networks, bandwidth and frequency variable gridless wavelength selective switches play an important role. In this paper, we summarize recent network revolution due to elastic optical path networks and also report the performance of gridless wavelength selective switches based on LCOS technology. Key words: wavelength selective switch WSS, liquid crystal on silicon LCOS, reconfigurable optical add-drop multiplexer ROADM, gridless, di ractive optical element DOE QAM quadrature amplitude modulation OFDM orthogonal frequency division multiplexing 1 2 ITU-T International Telecommunication Union Telecommunication Standardization Sector WDM wavelength division multiplexing WDM WDM LCOS liquid crystal on silicon ROADM reconfigurable optical add/drop multiplexer LCOS WSS: wavelength selective switch 1. ROADM/WXC ROADM 1 ROADM/WXC santec 485 0802 5823 E-mail: ysakurai@santec-net.co.jp 236 18
1 ROADM 3 2 WSS 3 WXC ROADM/WXC WDM / add/drop WDM O/E optical/ electrical E/O 2 WSS 3 WXC WSS 2 6 WSS mux/demux WDM add/drop WDM Tx / Rx mux/ demux Tx/Rx 3 / QAM OFDM 42 5 2013 400 Gbps 1 Tbps 4 5 10 Gbps 40 Gbps ROADM/WXC WSS ITU-T ROADM/WXC WDM WSS WDM 3 2. WSS ROADM/WXC WSS N 1 N 1 1 N 1 N mux/demux WDM demux, mux WDM WSS 4 WDM 237 19
5 LCOS 4 WSS WDM LC liquid crystal LCOS MEMS micro-electromechanical systems DMD digital mirror device 6 MEMS DMD LC LCOS MEMS LC WDM 1 DMD LCOS DMD on/o WSS LCOS ms DMD WSS 3. LCOS LCOS DOE: di ractive optical element LCOS 238 20 DOE 5 LCOS LCOS ITO indium tin oxide CMOS complementary metal oxide semiconductor Si DOE DOE 2p rad LCOS d q 2p rad l q in q d h q in q d m l L 1 h sin p q p q 2 2 L d q 3 m L DOE DOE LCOS WSS WSS 2 WSS AR antireflecticve LCOS LCOS LCOS 1920 1080 HDTV high definition televison 0 12 Vp-p 12 bit 8.0 mm 8.5 mm LCOS
8 1 4 WSS 6 1 7 3 5 65 0.05 db LCOS DOE 1 6 42 5 2013 DOE WSS DOE L l 4 7 2 Λ 1 π η exp jφ exp j 2 m x x dx 4 Λ Λ 0 F x DOE 8 DOE 2p rad 7 WSS 4. WSS 1 4 WSS 1 4 8 C PDL polarization dependent loss 6.5 db 35 db 0.5 db 0 db 165 110 20 mm WSS 1U 239 21
9 WSS 10 WSS 3 db TEC thermoelectric cooler TEC 30 50 W LCOS TEC 10 W 9 WSS C 96 9 50 GHz 0.5 db 3.0 db 45 GHz 38 GHz WDM WSS WSS 10 WSS 5 IL db 10 log exp ln 2 2 Dn BW 3 2n 5 Dn BW 3 n 3 db WSS 3 db m : 45.8 GHz / s : 0.43 GHz m : 0.09 GHz / s : 0.25 GHz WSS 3 db 10 WSS n 5.0 20 3 db 99.7 3s 34 GHz 11 240 22 11 WSS LCOS 11. WSS LCOS
1 M. Jinno, H. Takara, B. Kozicki, Y. Tsukishima, T. Yoshimatsu, T. Kobayashi, Y. Miyamoto, K. Yoneganaga, A. Takada, O. Ishida and S. Matsuoka: Demonstration of novel spectrume cient elastic optical path network with per-channel variable capacity of 40 Gb/s to over 400 Gb/s, Proc. of 34th European Conference on Optical Communication ECOC, Paper Th.3.F.6 2008. 2 M. Jinno, H. Takara, B. Kozicki, Y. Tsukishima, Y. Sone and S. Matsuoka: Spectrum-e cient and scalable elastic optical path network: Architecture, benefits, and enabling technologies, IEEE Commun. Mag., 47 2009 66 73. 3 P. Colbourne and B. Collings: ROADM switching technologies, Proc. of Optical Fiber Communication Conference and Exposition/National Fiber Optic Engineers Conference OFC/ NFOEC, Paper OTuD1 2011. 4 T. J. Xia, G. A. Wellbrock, Y. Huang, E. Ip, M. Huang, Y. Shao, T. Wang, Y. Aono, T. Tajima, S. Murakami and M. Cvijetic: Field experiment with mixed line-rate transmission 112-Gb/s, 450-Gb/s, and 1.15-Tb/s over 3,560 km of installed fiber using filterless coherent receiver and EDFas only, Proc. of Optical Fiber Communication Conference and Exposition/National Fiber Optic Engineers Conference OFC/NFOEC, Paper PDPA3 2012. 5 Y. Huang, E. Ip, P. N. Ji, Y. Shao, T. Wang, Y. Aono, Y. Yano and T. Tajima: Terabit/s optical superchannel with flexible modulation format for dynamic distance/route transmission, Proc. of Optical Fiber Communication Conference and Exposition/ National Fiber Optic Engineers Conference OFC/NFOEC, Paper OM3H.4 2012. 6 P. Wall, P. Colbourne, C. Reimer and S. McLaughlin: WSS switching engine technologies, Proc. of Optical Fiber Communication Conference and Exposition/National Fiber Optic Engineers Conference OFC/NFOEC, Paper OWC1 2008. 7 E. G. Loewen and E. Popov: Di raction Gratings and Applications CRC Press, New York, 1997 pp. 149 190. 8 J. Kelly: Application of liquid crystal technology to telecommunication devices, Proc. of Optical Fiber Communication Conference and Exposition/National Fiber Optic Engineers Conference OFC/NFOEC, Paper NThE1 2007. 9 LCOS 2012 C-3-20 2012. 10 F. Heismann: System requirements for WSS filter shape in cascaded ROADM networks, Proc. of Optical Fiber Communication Conference and Exposition/National Fiber Optic Engineers Conference OFC/NFOEC, Paper OThR1 2010. 11 K. Sone, X. Wang, S. Oda, G. Nakagawa, Y. Aoki, I. Kim, P. Palacharla, T. Hoshida, M. Sekiya and J. C. Rasmussen: First demonstration of hitless spectrum defragmentation using real-time coherent receivers in flexible grid optical networks, Proc. of 38th European Conference on Optical Communication ECOC, Paper Th.3.D.1 2012. 2012 12 6 42 5 2013 241 23