Optical locking based on optical resonators with high quality factors
First Claim
Patent Images
1. A device, comprising:
- a laser that produces a laser output beam at a laser frequency;
an optical interferometer located in an optical path of the laser output beam and comprising a first optical path that receives a first portion of the laser output beam, a second optical path that receives a second portion of the laser output beam, and an optical combiner where the first and second optical paths meet each other and terminate, the optical combiner (1) transmitting a part of light from the first optical path and reflecting a part of light from the second optical path to produce a first combined optical output, and (2) transmitting a part of the light from the second optical path and reflecting a part of the light from the first optical path to produce a second combined optical output;
an optical resonator optically coupled in the first optical path to filter light in the first optical path;
a detection module that detects the first and the second combined optical outputs to produce an error signal representing a frequency difference between the laser frequency and a resonance of the optical resonator; and
a feedback control mechanism that receives the error signal and tunes, one of (1) the laser and (2) the optical resonator, in response to the frequency difference of the error signal to lock the laser and the optical resonator with respect to each other.
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Abstract
Techniques and devices for providing optical locking of optical resonators and lasers.
105 Citations
25 Claims
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1. A device, comprising:
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a laser that produces a laser output beam at a laser frequency; an optical interferometer located in an optical path of the laser output beam and comprising a first optical path that receives a first portion of the laser output beam, a second optical path that receives a second portion of the laser output beam, and an optical combiner where the first and second optical paths meet each other and terminate, the optical combiner (1) transmitting a part of light from the first optical path and reflecting a part of light from the second optical path to produce a first combined optical output, and (2) transmitting a part of the light from the second optical path and reflecting a part of the light from the first optical path to produce a second combined optical output; an optical resonator optically coupled in the first optical path to filter light in the first optical path; a detection module that detects the first and the second combined optical outputs to produce an error signal representing a frequency difference between the laser frequency and a resonance of the optical resonator; and a feedback control mechanism that receives the error signal and tunes, one of (1) the laser and (2) the optical resonator, in response to the frequency difference of the error signal to lock the laser and the optical resonator with respect to each other. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for locking a laser and an optical resonator to each other, comprising:
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operating a laser to produce a laser output beam at a laser frequency without modulating the laser beam; directing laser light of the laser output beam into an optical interferometer which includes a first optical path and a second optical path that intersect to produce optical interference between light in the first and second optical paths; optically coupling an optical resonator in the first optical path to filter light in the first optical path; using two optical outputs of the optical interferometer to produce an error signal representing a frequency difference between the laser frequency of the laser and a resonance of the optical resonator; and tuning one of (1) the laser and (2) the optical resonator, in response to the frequency difference of the error signal, to lock the laser and the optical resonator with respect to each other. - View Dependent Claims (11, 12, 13, 14)
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15. A device that stabilizes a resonance of an optical resonator with respect to a laser frequency from a laser, comprising:
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a laser that produces a laser output beam at a laser carrier frequency; an optical resonator placed in an optical path of the laser output beam to receive light of the laser output beam; an optical coupler that couples the optical resonator to the optical path to receive the light of the laser output beam and to produce an optical output, the optical coupler structured and positioned relative to the optical resonator to provide, at an optical filter mode frequency different from the laser carrier frequency, optical coupling that is not under a critical coupling condition under which light coupled into the optical resonator is completely trapped inside the optical resonator; and an optical modulator, in the optical path of the laser output beam between the laser and the optical resonator, to modulate the laser output beam to produce a modulation sideband at which optical coupling of the light in the modulation sideband by the optical coupler into the optical resonator is near the critical coupling condition to thermally stabilize the resonator by optical absorption of light in the modulation sideband, wherein the modulation sideband is different in frequency from the optical filter mode frequency. - View Dependent Claims (16, 17, 18)
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19. A method for operating an optical resonator filter, comprising:
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directing to an optical resonator a resonator controlling laser beam at a laser carrier frequency that is modulated to carry a modulation sideband; operating an optical coupler to couple light at the modulation sideband into the optical resonator near a critical coupling condition under which light coupled into the optical resonator is completely trapped inside the optical resonator to thermally stabilize the resonator by optical absorption of light in the modulation sideband; directing an input optical signal, while the resonator is receiving and is thermally stabilized by the resonator controlling laser beam, through the optical resonator to perform optical filtering of the input optical signal by a resonance of the optical resonator at an optical filter mode frequency that is different from the modulation sideband and the laser carrier frequency of the resonator controlling laser beam. - View Dependent Claims (20, 21)
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22. A device for locking a laser to an optical resonator, comprising:
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a distributed feedback (DFB) laser that is tunable in response to a control signal and produces a laser beam at a laser frequency; an optical resonator structured to support a whispering gallery mode circulating in the optical resonator, the optical resonator being optically coupled to the DFB laser to receive a portion of the laser beam into the optical resonator in the whispering gallery mode and to feed laser light in the whispering gallery mode in the optical resonator back to the DFB laser to stabilize the laser frequency at a frequency of the whispering gallery mode and to reduce a linewidth of the DFB laser; and a resonator tuning mechanism that controls and tunes the frequency of the whispering gallery mode to tune the laser frequency of the DFB laser via the feedback of the laser light from the optical resonator to the DFB laser. - View Dependent Claims (23, 24, 25)
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Specification