Hybrid-Integrated Tunable Hollow Waveguide DBR Laser
We propose a novel hybrid-integrated tunable laser with a hollow waveguide distributed Bragg reflector, enabling a wide continuous tuning with a single-tuning parameter. The wavelength tuning of hollow waveguide lasers is demonstrated for the first time.
Fabrication and characterization of hollow waveguide distributed bragg reflectors
We present the fabrication and characterization of a novel distributed Bragg reflector consisting of a grating loaded slab hollow waveguide. In this structure, we are able to obtain a high reflectivity even by using thin and short surface gratings because of the large contrast in refractive indices between a grating material and an air-core. We fabricated a slab hollow waveguide Bragg reflector with 620µm long, 190nm deep 1st-order circular grating composed of SiO2 exhibiting strong Bragg reflection at 1558nm with an air-core thickness of 10µm for TM mode. The peak reflectivity is 65% including fiber coupling loss, the 3dB bandwidth is 2.8nm and the grating-induced loss is less than 0.5dB.
Modeling and Fabrication of Hollow Optical Waveguide for Photonic Integrated Circuits
We present the design and fabrication of hollow optical waveguides with highly reflective mirrors on the guiding walls of waveguides. We demonstrate the possibility of polarization-insensitive and low-loss slab waveguides by loading properly designed dielectric multilayer mirrors. We also propose a novel three-dimensional (3D) hollow waveguide with an etched groove structure for confining light in a lateral direction. We also predict that the propagation constant is independent of the ambient temperature, resulting in temperature-insensitive photonic waveguide devices such as optical filters and grating optical demultiplexers. We fabricate slab and 3D hollow optical waveguides with Au coating and present their propagation characteristics. The propagation loss of a slab waveguide was 1–2 dB/cm and 3–4 dB/cm for transverse electric (TE) and transverse magnetic (TM) modes, respectively. We also suggest the possibility of low-loss 3D hollow waveguides.