1 × 25 LCOS-based wavelength selective switch with flexible passbands and channel selection

Wavelength-selective-switching based reconfigurable optical add-drop multiplexers are the essential components of current and next generation dynamic optical networks. A proof-of-concept 1 × 25 wavelength selective switch is demonstrated experimentally based on liquid crystal on silicon (LCOS) technology and 2-foptical system. Each of the input C-band wavelength channel can be independently selected and switched into arbitrary output ports. The channel passband and channel spacing can be adjusted flexibly by applying holograms onto an LCOS chip. The insertion loss for polarized beam ranges from 5.4 to 7.5 dB for 1-20 output ports and increases up to 9.6 dB at side ports for 100 GHz spaced ITU-T channels over the C-band. The general channel crosstalk is below −20 dB. The minimum resolution of center frequency for each channel is 5 GHz (0.04 nm). The performance can be further improved by using an LCOS chip with smaller pixel pitch, higher-quality optical components and accurate alignment of the fiber-lenslet array.