Patent EP0104942A2 successfully refreshed from Google Patents.
EP0104942A2
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EP
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Brillouin ring laser
Assignee: Leland Stanford Junior University
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Filing: 1983-09-27
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Granted: —
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Expires: 2003-09-27
Abstract
Abstract A Brillouin ring laser comprises a fiber optic resonator formed from a loop (14) of fiber optic material (10) and a fiber optic directional coupler (20) for optically closing the loop (14).
Inventors
- 👤 Herbert John Shaw
- 👤 Marvin Chodorow
- 👤 Loren F. Stokes
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-28 19:52
CPC Classifications
H; H01; H01S; H01S3/00; H01S3/30; H01S3/302; G; G01; G01C; G01C19/00; G01C19/58; G01C19/64; G01C19/66; H01S3/05; H01S3/08; H01S3/081; H01S3/083
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
173 words
A Brillouin ring laser, comprising: a length of optical fiber (10) having first and second end portions (12, 16) and forming a loop portion (14) between said end portions (12, 16); a fiber optic coupler (20) for optically closing said loop portion (14), the length of said loop portion (14) selected to cooperate with said coupler (20) to form a resonant cavity; a light source (22) for introducing pump light into said first end portion (12) to provide a pump lightwave which propagates through said loop portion (14), said pump lightwave circulating through said resonant cavity and increasing in intensity to a level (P c ) which is greater than the intensity (P i ) of the pump light in said first end portion (12), said intensity level (Pc) sufficient to cause stimulated Brillouin scattering in said fiber loop portion (14) to provide a Brillouin wave which circulates through said fiber loop portion (14) in a direction opposite that of said pump lightwave, and is shifted in frequency relative to said pump lightwave.
Claim 2
Dependent Claim
173 words
A Brillouin ring laser, comprising: a length of optical fiber (10) having first and second end portions (12, 16) and forming a loop portion (14) between said end portions (12, 16); a fiber optic coupler (20) for optically closing said loop portion (14), the length of said loop portion (14) selected to cooperate with said coupler (20) to form a resonant cavity; a light source (22) for introducing pump light into said first end portion (12) to provide a pump lightwave which propagates through said loop portion (14), said pump lightwave circulating through said resonant cavity and increasing in intensity to a level (P c ) which is greater than the intensity (P i ) of the pump light in said first end portion (12), said intensity level (Pc) sufficient to cause stimulated Brillouin scattering in said fiber loop portion (14) to provide a Brillouin wave which circulates through said fiber loop portion (14) in a direction opposite that of said pump lightwave, and is shifted in frequency relative to said pump lightwave.
Claim 3
Dependent Claim
75 words
A Brillouin ring laser, as defined in Claim 1, wherein said intensity (P c ) of said circulating pump lightwave is greater than: where: A is the effective core area of said fiber (10); g is the Brillouin gain coefficient of said fiber (10); YO is the insertion loss of said coupler (20); a o is the amplitude attenuation coefficient of said fiber (10); and L is the length of the fiber loop portion (14).
Claim 4
Dependent Claim
32 words
A Brillouin ring laser, as defined in either of Claim 1 or 2, wherein said intensity (P i ) of said pump lightwave in said first end portion (12) is greater than:
Claim 5
Dependent Claim
33 words
A Brillouin ring laser, as defined in any of Claims 1 to 3, wherein the loop length (L) is chosen such that the fiber transmission losses are equal to the coupler insertion losses.
Claim 6
Dependent Claim
31 words
A Brillouin ring laser, as defined in any of Claims 1 to 4, wherein said intensity (Pi) of said pump lightwave in said first end portion (12) is less than 10mW.
Claim 7
Dependent Claim
224 words
A Brillouin ring laser, as defined in any of Claims 1 to 5, in the form of a rotation sensor, and further comprising: a detector (118) for detecting light from said second end portion (16); said source (22) further introducing a second input pump lightwave into said second end (16), said pump lightwaves propagating in opposite directions about said loop (14), both of said pump lightwaves at a resonant frequency of said loop (14), and having sufficient intensity to cause stimulated Brillouin scattering in said loop to provide said Brillouin wave and second Brillouin wave, said Brillouin waves counter-propagating relative to said and pump lightwave and said second pump lightwave, respectively, and resonating in said loop (14) at a frequency less than said pump lightwaves, the frequency at which each of said Brillouin waves resonates changing in response to rotation of said loop portion (14) to provide a frequency difference therebetween, indicative of the rotation rate of said loop portion (14); said fiber optic coupler coupling a fraction of each of said Brillouin waves from said loop (14) to form a Brillouin output wave, said Brillouin output wave having a beat. frequency equal to the difference in frequency between said Brillouin waves; and said second end portion (16) guiding said Brillouin output wave to said detector (118), said detector (118), detecting said beat frequency.
Claim 8
Independent Claim
54 words
A method of providing stimulated Brillouin oscillation in an optical fiber (10), comprising: forming a loop (14) in said fiber (10); optically closing said loop (14) with a fiber optic directional coupler (20); pumping said loop (14) with light at a resonant frequency of said loop (14) with sufficient intensity to cause Brillouin scattering.
Claim 9
Independent Claim
54 words
A method of providing stimulated Brillouin oscillation in an optical fiber (10), comprising: forming a loop (14) in said fiber (10); optically closing said loop (14) with a fiber optic directional coupler (20); pumping said loop (14) with light at a resonant frequency of said loop (14) with sufficient intensity to cause Brillouin scattering.
Claim 10
Dependent Claim
39 words
A method of providing stimulated Brillouin oscillation in an optical fiber, as defined in Claim 6, additionally comprising the step of: chosing the length of said loop (14) such that fiber transmission losses are equal to coupler insertion losses.
Claim 11
Independent Claim
157 words
A method of providing stimulated Brillouin oscillation, as defined in any of Claims 7-8, in order to sense rotation, wherein said pumping step further comprises introducing first and second input pump lightwaves into said fiber (10) for propagation in opposite directions about said loop (14), said pump lightwaves at a resonant frequency of said loop (14), and having sufficient intensity to cause stimulated Brillouin scatting in said loop to provide first and second Brillouin waves which counter-propogate relative to said first and second pump lightwaves, respectively, and which resonate in said loop (14), said method additionally comprising; rotating said loop (14) to provide a frequency difference between said Brillouin waves; coupling a fraction of said first and second Brillouin waves from said loop (14); combining said Brillouin waves to form a Brillouin output wave, said Brillouin output wave having a beat frequency equal to the difference in frequency between said Brillouin waves; and detecting said beat frequency.
Claim 12
Dependent Claim
15 words
The use of a Brillouin ring laser as defined in Claim 6 for sensing rotation.
References Cited (Backward Citations)
No citation records indexed.
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