Tunable filtering of RF or microwave signals based on optical filtering in Mach-Zehnder configuration
First Claim
Patent Images
1. A device, comprising:
- a laser to produce a laser beam at a laser carrier frequency;
an optical modulator to modulate the laser beam in response to an input signal to produce a modulated laser beam that carries the input signal;
an input optical port to receive the modulated laser beam;
a first optical path coupled to the input optical port to receive a first portion of the modulated laser beam and comprising a plurality of first tunable optical resonators optically cascaded to transmit light at the laser carrier frequency through the first optical path;
a second optical path coupled to the input optical port to receive a second portion of the modulated laser beam and comprising a plurality of second tunable optical resonators optically cascaded to transmit light at a selected optical frequency different from the laser carrier frequency through the second optical path;
an output optical port coupled to the first and second optical paths to combine transmitted light from the first and second optical paths to produce an output optical beam; and
an optical detector to convert the output optical beam into an output signal carrying a signal component of the input signal at a frequency that is a difference between the optical carrier frequency and the selected optical frequency.
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Abstract
Devices and techniques for achieving signal filtering in RF or microwave frequencies by optical filtering using two separate optical paths. Each optical path may include one or more optical resonators to achieve desired optical filtering.
148 Citations
17 Claims
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1. A device, comprising:
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a laser to produce a laser beam at a laser carrier frequency; an optical modulator to modulate the laser beam in response to an input signal to produce a modulated laser beam that carries the input signal; an input optical port to receive the modulated laser beam; a first optical path coupled to the input optical port to receive a first portion of the modulated laser beam and comprising a plurality of first tunable optical resonators optically cascaded to transmit light at the laser carrier frequency through the first optical path; a second optical path coupled to the input optical port to receive a second portion of the modulated laser beam and comprising a plurality of second tunable optical resonators optically cascaded to transmit light at a selected optical frequency different from the laser carrier frequency through the second optical path; an output optical port coupled to the first and second optical paths to combine transmitted light from the first and second optical paths to produce an output optical beam; and an optical detector to convert the output optical beam into an output signal carrying a signal component of the input signal at a frequency that is a difference between the optical carrier frequency and the selected optical frequency. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 17)
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9. A method for detecting an RF or microwave signal band carried by an optical signal, comprising:
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splitting an optical carrier beam at an optical carrier frequency that is modulated to carry a plurality of RF or microwave signal bands at optical frequencies different from the optical carrier frequency into a first beam and a second beam; directing the first beam through a first optical path having a plurality of optically cascaded first optical resonators that are in resonance at the optical carrier frequency to transmit, collectively, only light at the optical carrier frequency; directing the second beam through a second, separate optical path having a plurality of optically cascaded second optical resonators that are in resonance at an optical frequency at which a selected RF or microwave signal band is carried to transmit, collectively, only light at the optical frequency at which the selected RF or microwave signal band is carried; combining transmitted light from the first and second optical paths to produce an optical output; and using an optical detector to receive the optical output to recover the selected RF or microwave signal band. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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Specification