We propose a single-chip-based module that provides the entire switching/monitoring/equalizing/shuffling functionality needed in 8-channel fully reconfigurable optical add/drop multiplexers. This subsystem on a chip includes an array of switches for adding/dropping individual channels, optical power taps and integrated photodetectors for power monitoring, variable optical attenuators for channel power equalization, and optical cross-connects for channel shuffling at the add and drop ports for full wavelength agility. The chip is based on a polymer-on-silicon platform that allows hybrid integration of passive and active elements. Waveguiding circuitry is built in an optical polymer, and it includes thermo-optic switches, variable optical attenuators, and power taps. Out-of-plane coupling mirrors are formed by ablation of 45° slopes in the polymer waveguides with an Excimer laser, followed by metalization. A self-aligning flipchip process is used to mount photodetector arrays on top of mirrors fabricated in tap waveguides for power monitoring.
The worst-case fiber-to-fiber insertion loss for the proposed module, between 1528 and 1610 nm wavelength, is 1.2 dB from Input to Output (Express), including 4% tapped power, and 1.2 dB from Input to Drop and from Add to Output (4.1 dB with 8×8 shuffle cross-connects). The polarization dependent loss for any path is under 0.2 dB, and the polarization mode dispersion is under 0.05 ps. The channel-to-channel crosstalk is 50 dB, the switch extinction is 45 dB, and the return loss is 50 dB.