Design and optimization of a novel silicon-on-insulator wavelength diplexer

We propose a novel silicon-on-insulator (SOI) wavelength diplexer design based on an adiabatic bent taper and an unconventional multimode waveguide. The geometry of the device is optimized using particle swarm optimization (PSO). The device has an ultra-short length of 15 μm. Simulated insertion loss at peak wavelength is less than 0.25 dB with 1-dB bandwidth around 100 nm for both O band and C band. The device is fabrication tolerant as demonstrated by simulated yield estimates. The reported design targets 1310 and 1550 nm as peak wavelengths; the design methodology is easily applicable to other wavelengths of interest.