Integrated optical wavelength demultiplexer
First Claim
1. An integrated optical wavelength demultiplexer comprising a substrate, a thin film waveguide deposited on the substrate, input means for introducing multichromatic light from an optical fiber into the waveguide, collimating means within the waveguide for collimating the light at a wavelength dispersive element in the form of a thin-film prism, and focussing means within the waveguide for focussing specific wavelength components of the light separated by the dispersive element onto specific ones of an array of photodetectors formed underneath the waveguide.
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Accused Products
Abstract
An integrated optical wavelength demultiplexer has deposited on a waveguide layer a pair of Luneburg lenses, the first for collimating light from an optical fiber, the second for focussing light at an array of photodetectors formed under the waveguide layer. Between the lenses is the dispersive element, a thin-film prism of a highly dispersive low-loss material such as arsenic trisulfide. A known integrated optical demultiplexer, which uses a chirped diffraction grating to spatially disperse (rather than angularly disperse) the optical wavelengths, would suffer a greater insertion loss particularly for wavelengths coupled out at a later point in the grating. Demultiplexing with a thin-film prism should also result in the capability to handle a larger number of channels, for a given channel isolation and substrate area.
56 Citations
7 Claims
- 1. An integrated optical wavelength demultiplexer comprising a substrate, a thin film waveguide deposited on the substrate, input means for introducing multichromatic light from an optical fiber into the waveguide, collimating means within the waveguide for collimating the light at a wavelength dispersive element in the form of a thin-film prism, and focussing means within the waveguide for focussing specific wavelength components of the light separated by the dispersive element onto specific ones of an array of photodetectors formed underneath the waveguide.
Specification