| 摘要 |
An adaptive filter having a correlation weighting structue having a single Bragg cell, acting as a tapped delay line and having an input and an output, the Bragg cell intensity modulating a write laser beam for computing correlation values, and modulating a read laser field strength for multiplying the correlation values by delayed signal values. A photorefractive element is arranged such that substantial portions of diffracted and undiffracted light components from the single Bragg cell overlap within the photorefractive element. A write laser is intensity modulated by an error signal to produce an optical write signal that is received at the photorefractive element input and which writes correlation coefficients in the photorefractive element. A read laser produces a light signal, a portion of which is diffracted by the single Bragg cell, the portion of the light signal that is not diffracted by the single Bragg cell being partially diffracted by the photorefractive element. A photodetector having an input receives the portion of the light signal that is diffracted by the single Bragg cell and the portion of the read laser light signal that is diffracted by the photorefractive crystal, the photodetector output producing a filtered signal. The read laser light is isolated from the write laser light such that only the read laser light reaches the photodetector.
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