US4736164A
Expired / Lapsed
US
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Optical amplification
Assignee: British Telecommunications PLC
•
Filing: 1985-08-06
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Granted: 1988-04-05
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Expires: 2005-08-06
Abstract
Abstract Light is amplified in a semiconductor laser structure through which a current is passed and (a) the wavelength of the light is greater than the wavelength of maximum gain of the laser structure, or (b) injection locking is avoided, or (c) the current is controlled so as at least partly to compensate for the decrease in the monitored light output at a wavelength or over a wavelength range distinct from that of the emitted amplified signal. In this way relatively high input powers can be amplified.
Inventors
- 👤 Ian D. Henning
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 11:35
CPC Classifications
H; H01; H01S; H01S5/00; H01S5/50; H01S5/06; H01S5/068; H01S5/0683; H01S5/0687; H01S5/5063; H01S5/5081
Claims Analysis
Total Claims: 31
Claim 1
Independent Claim
107 words
A method of amplifying an optical signal which comprises coupling the optical signal to be amplified into the active layer of a semiconductor laser structure through which a driving current is passed, the amplified signal being emitted from the active layer, in which method the following relationship applies: λupper>λ>λmax wherein λupper is the longer of the two wavelengths of zero gain, at said driving current, for the low power limit of optical power input; λ is the wavelength of the optical signal to be amplified; and λmax is the wavelength of the gain maximum, at said driving current, for the low power limit of optical power input.
Claim 2
Independent Claim
107 words
A method of amplifying an optical signal which comprises coupling the optical signal to be amplified into the active layer of a semiconductor laser structure through which a driving current is passed, the amplified signal being emitted from the active layer, in which method the following relationship applies: λupper>λ>λmax wherein λupper is the longer of the two wavelengths of zero gain, at said driving current, for the low power limit of optical power input; λ is the wavelength of the optical signal to be amplified; and λmax is the wavelength of the gain maximum, at said driving current, for the low power limit of optical power input.
Claim 3
Dependent Claim
9 words
A method according to claim 1, wherein (λ-λ.sub.max)/(λ.sub.upper -λ.sub.max)≧0.1.
Claim 4
Dependent Claim
9 words
A method according to claim 1, wherein (λ-λ.sub.max)/(λ.sub.upper -λ.sub.max)≧0.2.
Claim 5
Independent Claim
19 words
A method according to any preceding claim wherein λ max is in the range from 1.2 to 1.7 μm.
Claim 6
Dependent Claim
20 words
A method according to claim 1, 2 or 3 wherein the driving current is such that lasing does not occur.
Claim 7
Independent Claim
40 words
A method according to any of claims 1 to 3, wherein the driving current is such that lasing occurs and the wavelength of the optical signal to be amplified is such that injection locking of the laser does not occur.
Claim 8
Independent Claim
62 words
A method of amplifying an optical signal which comprises coupling the signal to be amplified into the active layer of a semiconductor laser structure and applying a driving current to the laser structure such that lasing occurs, the wavelength of the signal to be amplified being such that injection locking is avoided and the amplified signal is emitted from the active layer.
Claim 9
Independent Claim
62 words
A method of amplifying an optical signal which comprises coupling the signal to be amplified into the active layer of a semiconductor laser structure and applying a driving current to the laser structure such that lasing occurs, the wavelength of the signal to be amplified being such that injection locking is avoided and the amplified signal is emitted from the active layer.
Claim 10
Dependent Claim
55 words
A method according to claim 7 wherein the output of the semiconductor laser structure is monitored at a wavelength or over a wavelength range distinct from that of the amplified signal and the driving current is controlled so as at least partly to compensate for the decrease in the monitored output with increased optical input.
Claim 11
Independent Claim
88 words
A method of amplifying an optical signal which comprises coupling the signal to be amplified into the active layer of a semiconductor laser structure through which a driving current is passed, which layer emits the amplified signal, and monitoring the light emission from the active layer at a wavelength or over a wavelength range distinct from that of the amplified signal, and controlling the driving current to the laser structure so as at least partly to compensate for the decrease in the monitored output with increasing optical input.
Claim 12
Independent Claim
88 words
A method of amplifying an optical signal which comprises coupling the signal to be amplified into the active layer of a semiconductor laser structure through which a driving current is passed, which layer emits the amplified signal, and monitoring the light emission from the active layer at a wavelength or over a wavelength range distinct from that of the amplified signal, and controlling the driving current to the laser structure so as at least partly to compensate for the decrease in the monitored output with increasing optical input.
Claim 13
Independent Claim
33 words
A method according to any one of claims 1, 7 or 9, wherein the signal to be amplified has a power which lies in the range from 1 μW to 5 mW inclusive.
Claim 14
Independent Claim
33 words
A method according to any one of claims 1, 7 or 9, wherein the signal to be amplified has a power which lies in the range from 10 μW to 5 mW inclusive.
Claim 15
Dependent Claim
124 words
An amplification assembly for amplifying an optical signal which comprises an optical signal source, a semiconductor laser structure, means for coupling the optical signal to be amplified into the active layer of the semiconductor laser structure, and means for passing a driving current through the semiconductor laser structure, the amplified signal being emitted from the active layer in use, wherein the following relationship applies: λupper>λ>λmax in which λupper is the longer of the two wavelengths of zero gain at said driving current, for the low power limit of optical power input; λ is the wavelength of the optical signal to be amplified; and λmax is the wavelength of the gain maximum, at said driving current, for the low power limit of optical power input.
Claim 16
Dependent Claim
124 words
An amplification assembly for amplifying an optical signal which comprises an optical signal source, a semiconductor laser structure, means for coupling the optical signal to be amplified into the active layer of the semiconductor laser structure, and means for passing a driving current through the semiconductor laser structure, the amplified signal being emitted from the active layer in use, wherein the following relationship applies: λupper>λ>λmax in which λupper is the longer of the two wavelengths of zero gain at said driving current, for the low power limit of optical power input; λ is the wavelength of the optical signal to be amplified; and λmax is the wavelength of the gain maximum, at said driving current, for the low power limit of optical power input.
Claim 17
Dependent Claim
9 words
An assembly according to claim 12, wherein (λ-λ.sub.max)/(λ.sub.upper -λ.sub.max)≧0.1.
Claim 18
Dependent Claim
9 words
An assembly according to claim 12, wherein (λ-λ.sub.max)/(λ.sub.upper -λ.sub.max)≧0.2.
Claim 19
Dependent Claim
22 words
An assembly according to any of claims 12 to 14 wherein λ max is in the range from 1.2 to 1.7 μm.
Claim 20
Dependent Claim
21 words
An assembly according to any of claims 12 to 14 wherein the driving current is such that lasing does not occur.
Claim 21
Dependent Claim
40 words
An assembly according to any of claims 12 to 14, wherein the driving current is such that lasing occurs and the wavelength of the optical signal to be amplified is such that injection locking of the laser does not occur.
Claim 22
Dependent Claim
77 words
An amplification assembly for amplifying an optical signal which comprises an optical signal source, a semiconductor laser structure, means for coupling the optical signal to be amplified into the active layer of the semiconductor laster structure, and means for passing a driving current through the semiconductor laser structure such that lasing occurs, the wavelength of the signal to be amplified being such that injection locking is avoided and the amplified signal being emitted from the active layer.
Claim 23
Dependent Claim
77 words
An amplification assembly for amplifying an optical signal which comprises an optical signal source, a semiconductor laser structure, means for coupling the optical signal to be amplified into the active layer of the semiconductor laster structure, and means for passing a driving current through the semiconductor laser structure such that lasing occurs, the wavelength of the signal to be amplified being such that injection locking is avoided and the amplified signal being emitted from the active layer.
Claim 24
Dependent Claim
138 words
An amplification assembly for amplifying an optical signal which comprises an optical signal source, a semiconductor laser structure, means for coupling the optical signal to be amplified into the active layer of the semiconductor laser structure, and means for passing a driving current through the semiconductor laser structure such that lasing occurs, the wavelength of the signal to be amplified being such that injection locking is avoided and the amplified signal being emitted from the active layer, wherein means is provided to monitor the output of the semiconductor laser structure at a wavelength or over a wavelength range distinct from that of the amplified signal and a feedback control loop is provided which acts to control the driving current so as at least partly to compensate for the decrease in the monitored output with increased optical input power.
Claim 25
Dependent Claim
138 words
An amplification assembly for amplifying an optical signal which comprises an optical signal source, a semiconductor laser structure, means for coupling the optical signal to be amplified into the active layer of the semiconductor laser structure, and means for passing a driving current through the semiconductor laser structure such that lasing occurs, the wavelength of the signal to be amplified being such that injection locking is avoided and the amplified signal being emitted from the active layer, wherein means is provided to monitor the output of the semiconductor laser structure at a wavelength or over a wavelength range distinct from that of the amplified signal and a feedback control loop is provided which acts to control the driving current so as at least partly to compensate for the decrease in the monitored output with increased optical input power.
Claim 26
Dependent Claim
120 words
An amplification assembly for amplifying an optical signal which comprises an optical signal source, a semiconductor laser structure, means for coupling the optical signal to be amplified into the active layer of the semiconductor laser structure, and means for passing a driving current through the semiconductor laser structure, the amplified signal being emitted from the active layer in use, wherein means is provided to monitor the output of the semiconductor laser structure at a wavelength or over a wavelength range distinct from that of the amplified signal and a feedback control loop is provided which acts to control the driving current so as at least partly to compensate for the decrease in the monitored output with increased optical input power.
Claim 27
Dependent Claim
120 words
An amplification assembly for amplifying an optical signal which comprises an optical signal source, a semiconductor laser structure, means for coupling the optical signal to be amplified into the active layer of the semiconductor laser structure, and means for passing a driving current through the semiconductor laser structure, the amplified signal being emitted from the active layer in use, wherein means is provided to monitor the output of the semiconductor laser structure at a wavelength or over a wavelength range distinct from that of the amplified signal and a feedback control loop is provided which acts to control the driving current so as at least partly to compensate for the decrease in the monitored output with increased optical input power.
Claim 28
Dependent Claim
33 words
An assembly according to any one of claims 12, 18 or 20, wherein the signal to be amplified has a power which lies in the range from 1 μW to 5 mW inclusive.
Claim 29
Dependent Claim
32 words
An assembly according to any one of claims 12, 18 or 20, wherein the signal to be amplified has a power which lies in the range from 10 μW to 5 mW.
Claim 30
Dependent Claim
33 words
An assembly according to any one of claims 12, 18 or 20, wherein the signal to be amplified has a power which lies in the range from 0.5 mW to 5 mW inclusive.
Claim 31
Dependent Claim
22 words
An assembly according to any one of claims 12, 18 or 20, wherein the semiconductor laser structure is of a Fabry-Perot type.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-04-05 | 1991-10-05 | 1992-04-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-04-05 | 1995-10-05 | 1996-04-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-04-05 | 1999-10-05 | 2000-04-05 | $7700.00 | Window Closed / Lapsed |