Patent US4492987A successfully refreshed from Google Patents.
US4941208A
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High performance subcarrier multiplexed optical communication system with modulation index exceeding unity
Assignee: Verizon Laboratories Inc
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Filing: 1988-09-08
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Granted: 1990-07-10
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Expires: 2008-09-08
Abstract
Abstract An optical communication system includes an optical transmitter for transmitting a subcarrier multiplexed optical signal through a single mode optical fiber to an optical receiver. The optical transmitter includes an optical source for generating a light beam. The optical source is preferably a high speed laser diode emitting in a spectral range of 1.3-1.6 micrometers. The light beam is intensity modulated with a composite modulation signal comprising multiple modulated microwave carriers. Each of the microwave carriers intensity modulates the light beam with a modulation index m i to provide the optical signal for transmission. The total modulation index M, defined by M=Σm i , of the optical signal exceeds unity without degradation of the signal-to-noise ratio. By permitting the total modulation index to exceed unity, a large number of microwave carriers can simultaneously be transmitted, and the information-carrying capacity of the optical communication system is enhanced.
Inventors
- 👤 Robert Olshansky
- 👤 Vincent Lanzisera
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 17:26
CPC Classifications
H; H04; H04J; H04J14/00; H04J14/02; H04J14/0298
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
73 words
Apparatus for transmitting an optical signal, comprising: means for generating a light beam; and means for intensity modulating the light beam with a composite modulation signal comprising a plurality of modulated microwave carriers, each of said microwave carriers intensity modulating said light beam with a modulation index m i to provide an optical signal for transmission, wherein the total modulation index M, defined by M=Σm.sub.i, of the optical signal is greater than one.
Claim 2
Dependent Claim
73 words
Apparatus for transmitting an optical signal, comprising: means for generating a light beam; and means for intensity modulating the light beam with a composite modulation signal comprising a plurality of modulated microwave carriers, each of said microwave carriers intensity modulating said light beam with a modulation index m i to provide an optical signal for transmission, wherein the total modulation index M, defined by M=Σm.sub.i, of the optical signal is greater than one.
Claim 3
Dependent Claim
30 words
Optical transmitting apparatus as defined in claim 1 further including: means for generating said modulated microwave carriers; and means for adding said modulated carriers to provide said composite modulation signal.
Claim 4
Dependent Claim
39 words
Optical transmitting apparatus as defined in claim 1 wherein said means for generating a light beam includes a semiconductor laser diode and wherein said intensity modulating means includes means for applying said composite modulation signal to said laser diode.
Claim 5
Dependent Claim
18 words
Optical transmitting apparatus as defined in claim 1 wherein the number of microwave carriers is at least three.
Claim 6
Dependent Claim
22 words
Optical transmitting apparatus as defined in claim 1 wherein the modulation index m i of each microwave carrier is at least 0.001.
Claim 7
Dependent Claim
26 words
Optical transmitting apparatus as defined in claim 3 wherein said laser diode is a high speed InGaAsP laser emitting in a spectral range of 1.3-1.6 micrometers.
Claim 8
Dependent Claim
23 words
Optical transmitting apparatus as defined in claim 1 wherein said microwave carriers are in the frequency range between about 2 and 20 gigahertz.
Claim 9
Independent Claim
112 words
A method for generating an optical signal that is intensity modulated by a plurality of microwave carriers, comprising the steps of: generating a light beam with a laser diode having sufficient modulation bandwidth to accommodate said plurality of microwave carriers; modulating each of said microwave carriers; combining said microwave carriers after frequency or phase modulation thereof to provide a composite modulation signal; and intensity modulating said light beam with said composite modulation signal to provide an optical signal, each of said microwave carriers intensity modulating the optical signal with a modulation index m i , wherein the total modulation index M, defined by M=Σm.sub.i, of the optical signal is greater than one.
Claim 10
Independent Claim
112 words
A method for generating an optical signal that is intensity modulated by a plurality of microwave carriers, comprising the steps of: generating a light beam with a laser diode having sufficient modulation bandwidth to accommodate said plurality of microwave carriers; modulating each of said microwave carriers; combining said microwave carriers after frequency or phase modulation thereof to provide a composite modulation signal; and intensity modulating said light beam with said composite modulation signal to provide an optical signal, each of said microwave carriers intensity modulating the optical signal with a modulation index m i , wherein the total modulation index M, defined by M=Σm.sub.i, of the optical signal is greater than one.
Claim 11
Independent Claim
81 words
A method for transmitting an optical signal, comprising the steps of: generating a light beam; intensity modulating the light beam with a composite modulation signal comprising a plurality of modulated microwave carriers, each of said microwave carriers intensity modulating said optical signal with a modulation index m i to provide an optical signal for transmission, wherein the total modulation index M, defined by M=Σm.sub.i, of the optical signal is greater than one; and transmitting the optical signal to a remote location.
Claim 12
Independent Claim
81 words
A method for transmitting an optical signal, comprising the steps of: generating a light beam; intensity modulating the light beam with a composite modulation signal comprising a plurality of modulated microwave carriers, each of said microwave carriers intensity modulating said optical signal with a modulation index m i to provide an optical signal for transmission, wherein the total modulation index M, defined by M=Σm.sub.i, of the optical signal is greater than one; and transmitting the optical signal to a remote location.
Claim 13
Dependent Claim
29 words
A method for transmitting an optical signal as defined in claim 9 wherein the step of transmitting the optical signal includes transmitting the optical signal on an optical fiber.
Claim 14
Dependent Claim
34 words
A method for transmitting an optical signal as defined in claim 9 further including the steps of generating said modulated microwave carriers, and adding said modulated microwave carriers to provide said composite modulation signal.
Claim 15
Dependent Claim
129 words
Optical communication apparatus comprising: transmitter means including means for generating a light beam and means for intensity modulating the light beam with a composite modulation signal comprising a plurality of modulated microwave carriers, each of said microwave carriers intensity modulating said light beam with a modulation index m i to provide an optical signal for transmission, wherein the total modulation index M, defined by M=Σm.sub.i, of the optical signal is greater than one; receiver means remotely located from said transmitter means, including a detector responsive to said optical signal for providing said composite modulation signal and a receiver for separating and demodulating at least one of said microwave carriers from said composite modulation signal; and means for coupling said optical signal from said transmitter means to said receiver means.
Claim 16
Dependent Claim
129 words
Optical communication apparatus comprising: transmitter means including means for generating a light beam and means for intensity modulating the light beam with a composite modulation signal comprising a plurality of modulated microwave carriers, each of said microwave carriers intensity modulating said light beam with a modulation index m i to provide an optical signal for transmission, wherein the total modulation index M, defined by M=Σm.sub.i, of the optical signal is greater than one; receiver means remotely located from said transmitter means, including a detector responsive to said optical signal for providing said composite modulation signal and a receiver for separating and demodulating at least one of said microwave carriers from said composite modulation signal; and means for coupling said optical signal from said transmitter means to said receiver means.
Claim 17
Dependent Claim
18 words
Optical communication apparatus as defined in claim 12 wherein said coupling means comprises a single mode optical fiber.
Claim 18
Dependent Claim
35 words
Optical communication apparatus as defined in claim 12 wherein said transmitter means further includes; means for generating said modulated microwave carriers; and means for adding said modulated microwave carriers to provide said composite modulation signal.
Claim 19
Dependent Claim
39 words
Optical communication apparatus as defined in claim 12 wherein said means for generating a light beam includes a semiconductor laser diode and wherein said intensity modulating means includes means for applying said composite modulation signal to said laser diode.
References Cited (Backward Citations)
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 7.5 Years (Year 8) | 1997-07-09 | 1998-01-08 | 1998-07-10 | $3760.00 | Window Closed / Lapsed |
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