Low-Loss Polarization-Insensitive Silicon-on-Insulator-Based WDM Filter for Triplexer Applications

We have designed and fabricated a low-loss polarization-insensitive silicon-on-insulator-based photonic integrated circuit wavelength-division-multiplexing transceiver filter for triplexer applications. The filter is realized by two-stage Fourier-transform-based Mach-Zehnder interferometers to handle the uploading of 1.3-mum data stream and the demultiplexing of 1.49-mum/1.55-mum channels for downstream traffics, respectively. The fabricated filter has less than 0.2-dB ripple over 20-nm flat passband for downstream channels and more than 100-nm bandwidth for the upstream channel. The excess loss of the filter is less than 0.35 dB with less than 0.1-dB polarization-dependent loss.