Tunable Optical Filter With Cascaded Waveguide Fabry–Pérot Resonators Featuring Liquid Crystal Cladding

We developed and fabricated a tunable optical filter using Si-waveguide multiple-cavity Fabry-Pérot resonators with ferro-electric liquid crystal cladding. The proposed filter can be monolithically integrated with other Si photonics devices because no cleaved facets are required. Also, the bistable characteristic of ferro-electric liquid crystal cladding means the power consumption is low. We tested wavelength operation in the fabricated device and determined that it was able to obtain a phase shift of 0.38 π. It also had improved resonant wavelength characteristics.