Design of cascaded volume holographic gratings to increase the number of channels for an optical demultiplexer

Abstract

The design and demonstration of a holographic optical demultiplexer based on cascaded volume holographic gratings are presented. By serially adding a second holographic grating, which has a different grating period, slant angle, and center wavelength compared with those of the first grating, the operating wavelength range of the optical demultiplexer could be expanded, and, therefore, the number of channels of the holographic demultiplexer is doubled. As a result of the experiment, a 0.4 nm spaced 130- channel demultiplexer with a channel uniformity of 3.5 dB, a 3 dB bandwidth of 0.12 nm, and channel cross talk of -20 dB is experimentally achieved.

Fabrication of Microholographic Gratings on Al2O3 Grown by Atomic Layer Deposition Using a Femtosecond Laser

“…An optical grating can be encoded on a sample surface by two-beam interference using a single near-infrared femtosecond laser pulse [1,2]. Diffraction gratings have been commonly fabricated on silver halide emulsion, photoresist, and photopolymer optical materials, for example [3][4][5]. With individual femtosecond laser pulses, permanent gratings have been encoded on surfaces of glass, crystal, and silicon dioxide thin film [6][7][8][9].…”