EP0174729A1
Expired / Lapsed
EP
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Optical amplification
Assignee: British Telecommunications PLC
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Filing: 1985-08-06
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Granted: —
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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 Douglas Henning
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-31 16:44
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: 30
Claim 1
Independent Claim
112 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 wavelength of the gair maximum at that driving current for the low power limit of optical power input λ max , the longer of the two wavelengths of zero gain at the driving currert for the low power limit of optical power input λ upper , and the wavelength of the optical signal to be amplified are related by the equatior, λ upper >λ >λ max .
Claim 2
Independent Claim
112 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 wavelength of the gair maximum at that driving current for the low power limit of optical power input λ max , the longer of the two wavelengths of zero gain at the driving currert for the low power limit of optical power input λ upper , and the wavelength of the optical signal to be amplified are related by the equatior, λ upper >λ >λ max .
Claim 3
Dependent Claim
19 words
A method according to claim 1, wherein (λ - λ max )/(λ upper - λ max ) ≥ 0.1.
Claim 4
Dependent Claim
18 words
A method according to claim 1, whereir (λ - λ max )/(λ upper - λ max )≥ 0.2.
Claim 5
Independent Claim
18 words
A method according to any preceding claim wherein λ max is in the range from 1.2 to 1.7µm.
Claim 6
Independent Claim
18 words
A method according to any preceding claim 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 4, wherein the driving current is such that lasirg occurs and the wavelength of the optical signal to be amplified is such that irjectior 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 lading occurs, the wavelength of the sigral 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 lading occurs, the wavelength of the sigral to be amplified being such that injection locking is avoided and the amplified signal is emitted from the active layer.
Claim 10
Independent Claim
60 words
A method according to any one of claims 1 to 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 ir the monitored output with increased optical input.
Claim 11
Independent Claim
88 words
A method of amplifying ar 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 moritorirg the light emission from the active layer at a wavelergth or over a wavelength range distinct from that of the amplified signal, and controlling the driving currert to the laser structure so as at least partly to compersate for the decrease in the monitored output with increasing optical input.
Claim 12
Independent Claim
88 words
A method of amplifying ar 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 moritorirg the light emission from the active layer at a wavelergth or over a wavelength range distinct from that of the amplified signal, and controlling the driving currert to the laser structure so as at least partly to compersate for the decrease in the monitored output with increasing optical input.
Claim 13
Independent Claim
26 words
A method according to any preceding claim, wherein the signal to be amplified has a power which lies in the range from 1µW to 5mW inclusive.
Claim 14
Independent Claim
26 words
A method according to any preceding claim, whereir the signal to be amplified has a power which lies in the range from 10µW to 5mW inclusive.
Claim 15
Dependent Claim
124 words
An amplificatior assembly for amplifying an optical signal which comprises an optical signal source, a semiconductor laser structure, means for coupling the optical sigral 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 sigral being emitted from the active layer in use, wherein the wavelength of the gair maximum of the semiconductor laser structure at that driving current for the low power limit of optical power input λ max , the longer of the two wavelengths of zero gair at the driving current λ upper , and the wavelength of the optical sigral to the amplified are related by the equation λ upper >λ > λ max
Claim 16
Dependent Claim
124 words
An amplificatior assembly for amplifying an optical signal which comprises an optical signal source, a semiconductor laser structure, means for coupling the optical sigral 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 sigral being emitted from the active layer in use, wherein the wavelength of the gair maximum of the semiconductor laser structure at that driving current for the low power limit of optical power input λ max , the longer of the two wavelengths of zero gair at the driving current λ upper , and the wavelength of the optical sigral to the amplified are related by the equation λ upper >λ > λ max
Claim 17
Dependent Claim
18 words
An assembly according to claim 12, wherein (λ-λ max )/ (λ upper - λ max ) ≥ 0.1
Claim 18
Dependent Claim
17 words
An assembly according to claim 12, wherein (λ-λ max )/ (λ upper - λ max )≥ 0.2
Claim 19
Dependent Claim
21 words
An assembly according to any of claims 12 to 14 wherein λ max is in the range from 1.2 to 1.7µm.
Claim 20
Dependent Claim
21 words
An assembly according to any of claims 12 to 15 wherein the driving current is such that lasing does not occur.
Claim 21
Dependent Claim
40 words
An assembly according to ary of claims 12 to 15, wherein the driving current is such that lasing occurs and the wavelength of the optical sigral to be amplified is such that irjectior 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
72 words
An assembly according to ary one of claims 12 to 18 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 cortrol 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
120 words
An amplificatior 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 sigral and a feedback control loop is provided which acts to cortrol the driving current so as at least partly to compensate for the decrease in the moritored output with increased optical input power.
Claim 26
Dependent Claim
120 words
An amplificatior 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 sigral and a feedback control loop is provided which acts to cortrol the driving current so as at least partly to compensate for the decrease in the moritored output with increased optical input power.
Claim 27
Dependent Claim
30 words
An assembly according to any one of claims 12 to 20, whereir. the sigral to be amplified has a power which lies in the range from 1µW to 5mW inclusive.
Claim 28
Dependent Claim
29 words
An assembly according to any one of claims 12 to 20, wherein the signal to be amplified has a power which lies in the range from 10µW to 5mW.
Claim 29
Dependent Claim
30 words
An assembly according to any one of claims 12 to 20, wherein the signal to be amplified has a power which lies in the rarge from 0.5mW to 5mW inclusive.
Claim 30
Dependent Claim
21 words
An assembly according to any one of claims 12 to 23, wherein the semiconductor laser structure is of a Fabry-Perot type.
References Cited (Backward Citations)
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