Optical add-drop multiplexers based on the antisymmetric waveguide Bragg grating.

A novel optical add-drop multiplexer (OADM) based on a null coupler with an antisymmetric grating was designed and experimentally demonstrated. The antisymmetric grating exclusively produces a reflection with mode conversion in a two-mode waveguide. This improves the performance compared with previous demonstrations that used tilted Bragg gratings.

Demonstration of mode conversion using anti-symmetric waveguide Bragg gratings.

We experimentally demonstrate a novel grating which only produces reflection with mode conversion in a two-mode waveguide. That characteristic can improve the performance of optical devices that currently use tilted Bragg gratings to provide the mode conversion. Tilted Bragg gratings produce also reflections without mode conversion which increases noise and crosstalk of the optical device.

Low-loss silica-on-silicon two-dimensional Fabry-Perot cavity based on holographic Bragg reflectors.

We report on the demonstration of an integrated slab-waveguide-based concentric Fabry-Perot resonator that employs holographic Bragg reflectors as cavity mirrors. The cavity, produced in a low-loss silica-on-silicon slab waveguide by high-fidelity deep-ultraviolet photolithographic fabrication, exhibits a reflectivity-limited Q factor of approximately 10(5). Increasing the mirror's reflectivity will provide Q values similar to those of silica-based ring resonators, whereas the folded Fabry-Perot resonator design allows access to a substantially larger free spectral range by cavity shortening.

Wavelength division multiplexing based on apodized planar holographic Bragg reflectors.

We report wavelength division multiplexing based on lithographically fabricated slab-waveguide-contained planar holographic Bragg reflectors (HBRs). Partial HBR diffractive contour writing and contour displacement are successfully demonstrated to enable precise bandpass engineering of multiplexer transfer functions and make possible compact-footprint devices based on hologram overlay. Four- and eight-channel multiplexers with channel spacings of approximately 50 and approximately 100 GHz, improved sidelobe suppression, and flattop passbands are demonstrated.

Bandpass engineering of lithographically scribed channel-waveguide Bragg gratings.

We propose and demonstrate a powerful approach to spectral bandpass engineering (apodization) of one-dimensional channel-waveguide Bragg reflectors. Bandpass engineering is accomplished by precise photolithographic control of the length and the longitudinal placement of individual grating lines, which provides unique line-by-line diffractive amplitude and phase control. Channel-waveguide gratings that exhibit complex filtering functions have been fabricated and modeled.