A High-Performance Ultracompact Optical Interleaver Based on Double-Ring Assisted Mach–Zehnder Interferometer

We present an ultracompact and high-performance optical interleaver based on a microring assisted Mach-Zehnder interferometer using an ultrahigh-index-contrast waveguide (17% Delta). The device, a 100/200-GHz interleaver at 1.55-mum region, exhibits flat and nearly square passband and better than -30-dB stopband extinction ratio. Fiber-to-fiber loss is -2.2 dB. Passband bandwidth is 90 and 121 GHz at -1 and -20 dB, respectively. The dimension of this interleaver chip is 12times1 mm. Design optimization is also discussed for further performance improvement.