Crosstalk-Free 32-ch DWDM Demultiplexer On Standard Si Pic Platform Enabled By Fully-Integrated Cascaded AMZ Triplet

Enabled by an autonomous calibration mechanism, crosstalk-free (−38.5 dB) fabrication-tolerant 32-ch DWDM demultiplexer on a standard Si PIC platform is demonstrated for the first time. On this platform, due to its nano-sized waveguide core dimensions, extremely precise fabrication control of waveguides has been required so far to suppress the crosstalk of demultiplexers for large-channel-count DWDM systems. This requirement made this platform impractical for such systems. To exclude this requirement, we have proposed a calibration mechanism which can be fully integrated into an assembly composed of an electric IC (EIC) and a standard Si PIC. The Si PIC has a structure of cascaded asymmetric Mach-Zehnder (AMZ) triplet consisting of AMZ interferometers designed to function as a demultiplexer. This structure enables monitoring the errors in the optical lengths of waveguides composing itself. Based on the monitored values, the controller implemented on the EIC determines the driving conditions of waveguide heaters to eliminate the errors. This feature excludes the necessity to strictly control the optical lengths in the fabrication process, making it possible to realize a crosstalk-free 32-ch DWDM demultiplexer on a standard Si PIC platform. Compatible with the vast component libraries of standard Si PIC platform, this device provides a path to ultrahigh-capacity integrated DWDM transceivers.