Optical transversal filter
First Claim
1. An optical transversal filter for processing an electromagnetic input signal comprising:
- a light source adapted to generate a plurality of optical signals modulated in correspondence with said input signal;
a plurality of optical time delay units optically coupled in a cascade, said cascade being optically coupled to said light source and adapted to differentially time delay selected ones of said plurality of optical signals passing therethrough;
an optical trimmer device optically coupled to the last of said optical time delay units in said cascade; and
a filter output assembly coupled to said optical trimmer device, said filter output assembly being adapted to convert the sum of the plurality of processed optical signals to a corresponding filtered electrical signal;
each of said optical time delay units comprising a spatial light modulator (SLM) having an array of liquid crystal pixels disposed such that respective ones of said optical signals pass through respective pixels.
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Accused Products
Abstract
An optical transversal filter includes a processing system having a light source adapted to be modulated by an input electromagnetic signal and generate a plurality of collimated optical signals, a cascade of optical time delay units sequentially coupled to act upon the collimated optical signals passing from the light source to selectively differentially time delay respective ones of the optical signals, an optical trimmer device coupled to receive the differentially time delayed optical signals and to selectively attenuate respective ones of those signals, and a filter output assembly which receives and sums the optical signals from the trimmer device optically and converts the sum to a corresponding filtered electrical signal, or alternatively, converts the respective optical signals to electrical signals and electrically sums the signals. Each optical time delay unit includes a spatial light modulator having liquid crystal pixels disposed such that the polarization orientation of each respective optical signal is controlled by passing respective optical signals through respective ones of the pixels. Dependent on its polarization orientation, each optical signal passes through a delay assembly optically coupled to the respective spatial light modulator in the optical time delay unit on either a direct path or a delay path.
31 Citations
26 Claims
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1. An optical transversal filter for processing an electromagnetic input signal comprising:
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a light source adapted to generate a plurality of optical signals modulated in correspondence with said input signal; a plurality of optical time delay units optically coupled in a cascade, said cascade being optically coupled to said light source and adapted to differentially time delay selected ones of said plurality of optical signals passing therethrough; an optical trimmer device optically coupled to the last of said optical time delay units in said cascade; and a filter output assembly coupled to said optical trimmer device, said filter output assembly being adapted to convert the sum of the plurality of processed optical signals to a corresponding filtered electrical signal; each of said optical time delay units comprising a spatial light modulator (SLM) having an array of liquid crystal pixels disposed such that respective ones of said optical signals pass through respective pixels. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A method of filtering a wideband signal with an optical transversal filter comprising the steps of:
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modulating a laser source with said wideband signal to generate a plurality of corresponding optical signals, each of said optical signals comprising respective temporally synchronized pulses; processing said plurality of optical signals in a beam processing system so as to selectively time delay individual ones of said optical signals to generate a desired differential time delay between the respective ones of the pulses in said optical signals; attenuating selected ones of the respective optical signals emanating from said beam processing system by passing the signals through an optical analog trimmer device; and summing the plurality of optical signals and generating a corresponding electrical signal. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26)
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Specification