| 摘要 |
We describe an optical spectral filtering device and associated method for selectively directing a portion of a wavelength multiplexed input signal, entering through an optical fiber, into one or more output signals provided to one or more optical fibers and/or electronic outputs. The optical filtering is accomplished using free-space diffractive wavelength demultiplexing optics combined with a fixed (permanent) patterned structure located in the spectrally dispersed image plane. The structure can block or direct a selected spectral portion of the optical signal to one or more separate outputs, such as an optical fiber or power detector. A single active element in the optical path is used to spatially shift, or steer, the entire input spectrum at the dispersed spectral image plane, to control the portion of the input spectrum illuminating specific features on the permanent patterned structure. In one preferred embodiment, a variable-bandwidth tunable optical spectral power meter is constructed using an optical power detector with a fixed wedge-shaped aperture to detect a portion of a wavelength multiplexed input signal, and a tilting mirror is used to control the signal entering the detector, such that tilting the mirror in one axis will adjust the center wavelength of the signal being detected and tilting the mirror in the orthogonal axis adjusts the spectral bandwidth of the detected signal.
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