Demonstration of Multi-Casting in a 1 × 9 LCOS Wavelength Selective Switch

• Published in: Journal of lightwave technology 2014-02, Vol.32 (3), p.402-410
• Main Authors: Robertson, Brian, Haining Yang, Redmond, Maura M., Collings, Neil, Moore, John R., Jinsong Liu, Jeziorska-Chapman, Anna M., Pivnenko, Mike, Lee, Sharon, Wonfor, Adrian, White, Ian H., Crossland, William A., Chu, D. P.
• Format: Article
• Language: English
• Subjects: Algorithm design and analysis; Applied sciences; Circuit properties; Crosstalk; Electric, optical and optoelectronic circuits; Electronics; Exact sciences and technology; Information, signal and communications theory; Insertion loss; Integrated optics. Optical fibers and wave guides; Liquid crystal on silicon; Multi-casting; Multicast communication; Multiplexing; Optical and optoelectronic circuits; optical fiber communication; Optical fiber communications; Optical switches; Optical telecommunications; Optimization; Signal and communications theory; Switching and signalling; Systems, networks and services of telecommunications; Telecommunications; Telecommunications and information theory; wavelength division multiplexing; wavelength selective switch
• ISSN: 0733-8724; 1558-2213
• DOI: 10.1109/JLT.2013.2293919

A multi-functional 1 × 9 wavelength selective switch based on liquid crystal on silicon (LCOS) spatial light modulator technology and anamorphic optics was tested at a channel spacing of 100 and 200 GHz, including dynamic data measurements on both single beam deflection and multi-casting to two ports. The multi-casting holograms were optimized using a modified Gerchberg-Saxton routine to design the core hologram, followed by a simulated annealing routine to reduce crosstalk at non-switched ports. The effect of clamping the magnitude of phase changes between neighboring pixels during optimization was investigated, with experimental results for multi-casting to two ports resulting in a signal insertion loss of -7.6 dB normalized to single port deflection, a uniformity of ±0.6%, and a worst case crosstalk of -19.4 dB, which can all be improved further by using a better anti-reflection coating on the LCOS SLM coverplate and other measures.