$8\times 8$ Flexible Wavelength Cross-Connect for CDC ROADM Application

We propose and demonstrate an 8 × 8 flexible wavelength cross-connect (FWXC) switch that supports flex-grid wavelength assignment switching with contentionless feature. The developed switch is characterized for insertion loss, passband, frequency-tuning granularity, and port crosstalk. Based on the FWXC, we experimentally demonstrate a novel ultracompact colorless/directionless/contentionless-reconfigurable optical add drop multiplexer supporting four directions. Mixed 10G/40G/100G signals on add, drop, and express paths are tested. The optical signal-to-noise ratio (OSNR) penalties are observed <;0.25 dB for all the cases.