EP0469259A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Optical oscillator sweeper
Assignee: HP Inc
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Filing: 1991-05-22
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Granted: —
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Expires: 2011-05-22
Abstract
Abstract An external cavity laser is formed by feeding back light from a laser (102, 150, 202) through two or more acoustooptic tuneable filters (AOTF#1, AOTF#2, 210) back to the laser. The Doppler shifts introduced by the filters do not entirely cancel. The net Doppler shift caused by the filters is continuously tuned to cause the bandpass of the filter to follow the shifting resonating frequency of the laser to prevent mode hopping.
Inventors
- 👤 William R. Trutna, Jr.
- 👤 Paul Zorabedian
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-25 08:01
CPC Classifications
H; H01; H01S; H01S3/00; H01S3/10; H01S3/106; H01S3/1068; G; G02; G02B; G02B6/00; G02B6/24; G02B6/42; G02B6/4201; G02B6/4202; G02B6/4203; H01S3/13; H01S3/136; H01S3/137; H01S5/00; H01S5/06; H01S5/065; H01S5/10; H01S5/14; H01S5/141
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
163 words
An optical oscillator comprising: oscillator means for providing light of one or more longitudinal modes within a first pass band, the bandwidth of said bandpass being within a second predetermined gain bandwidth of the oscillator means, said oscillator means including a laser (102, 150, 202) for providing light and feedback means for feeding light from the laser back to the laser in a feedback path to cause light emission in said modes; and a plurality of acoustooptic tuneable filters (AOTF#1, AOTF#2, 210) in the feedback path, each filter causing a Doppler shift of the longitudinal mode frequencies, wherein the filters are such that the Doppler shifts caused by said plurality of filters do not entirely cancel to thereby cause a net Doppler shift of the longitudinal mode frequencies, said net Doppler shift being continuously adjustable to cause the longitudinal modes to sweep the second predetermined bandwidth and to cause the bandpass bandwidth to follow the sweeping modes in order to prevent mode hopping.
Claim 2
Dependent Claim
163 words
An optical oscillator comprising: oscillator means for providing light of one or more longitudinal modes within a first pass band, the bandwidth of said bandpass being within a second predetermined gain bandwidth of the oscillator means, said oscillator means including a laser (102, 150, 202) for providing light and feedback means for feeding light from the laser back to the laser in a feedback path to cause light emission in said modes; and a plurality of acoustooptic tuneable filters (AOTF#1, AOTF#2, 210) in the feedback path, each filter causing a Doppler shift of the longitudinal mode frequencies, wherein the filters are such that the Doppler shifts caused by said plurality of filters do not entirely cancel to thereby cause a net Doppler shift of the longitudinal mode frequencies, said net Doppler shift being continuously adjustable to cause the longitudinal modes to sweep the second predetermined bandwidth and to cause the bandpass bandwidth to follow the sweeping modes in order to prevent mode hopping.
Claim 3
Dependent Claim
76 words
The oscillator of claim 1, further comprising means (222, 224, 226, 252, 254, 256) for driving the filters at different frequencies such that the Doppler shifts caused by said plurality of filters do not entirely cancel, said driving means being such that the driving frequencies are continuously adjustable to cause the longitudinal modes to sweep the second predetermined bandwidth and to cause the bandpass bandwidth to follow the sweeping modes in order to prevent mode hopping.
Claim 4
Dependent Claim
59 words
The oscillator of claim 1, wherein the light provided by the laser passes through the filters twice, so that the oscillator chirps at a rate that is given by twice the net difference in frequency between the filters divided by the time required for the light to propagate from the laser back to the laser through the feedback path.
Claim 5
Dependent Claim
11 words
The oscillator of claim 3, said feedback means including a mirror.
Claim 6
Dependent Claim
11 words
The oscillator of claim 3, said feedback means including two mirrors.
Claim 7
Dependent Claim
12 words
The oscillator of claim 1, said feedback means including an optical fiber.
Claim 8
Dependent Claim
58 words
The oscillator of claim 6, wherein the light provided by the laser passes through the filters once, so that the oscillator chirps at a rate that is given by the net difference in frequency between the filters divided by the time required for the light to propagate from the laser back to the laser through the feedback path.
Claim 9
Dependent Claim
56 words
The oscillator of claim 1, said laser having a cavity with two antireflection coatings (152, 154), said light provided by the laser passing from the laser cavity through one coating to the feedback path and back to the laser through the other coating in the feedback path so that spurious oscillations in the cavity are reduced.
Claim 10
Dependent Claim
12 words
The oscillator of claim 1, wherein said laser is a semiconductor laser.
References Cited (Backward Citations)
No citation records indexed.
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