Tunable hollow optical waveguides for photonic integrated circuits

Abstract

We propose a tunable hollow optical waveguide with a variable air core toward a new class of photonic integrated circuits. We present various unique features in hollow waveguides and the combination with microelectro-mechanical system (MEMS) will gives us widely tunable waveguide devices. We presente the design and fabrication of a tunable hollow waveguide with a variable air core. We describe the full-vectorial modeling of 3D and slab hollow waveguides with a variable air core, which is also supported by experiments. We demonstrated low loss and polarization insensitive waveguiding in an air core with optimized multilayer coating. The result shows a possibility of a large change of ~3% in propagation constant with a variable air core. We will present a wide variety of device applications based on hollow waveguides, which include tunable grating demultiplexers, variable attenuators, optical switches, tunable Bragg reflectors, tunable dispersion compensators and tunable lasers. The device structure can be formed by fully planar fabrication processes based on lithography and etching. The proposed concept may open up a new class of various tunable optical devices, which give us unique features of wide tunability, compact size and temperature insensitivity.