Synchronizing nodes in an optical communications system utilizing frequency division multiplexing
First Claim
1. In an optical fiber communications system including a transmitter node coupled to a receiver node by an optical fiber, a method for synchronizing the receiver node with the transmitter node, the method comprising:
- at the transmitter node;
generating a reference signal;
synchronizing the transmitter node with the reference signal;
wherein said synchronizing the transmitter node comprises adjusting the data rate of a data signal to match the rate of the reference signal;
modulating the reference signal onto an optical signal in a first frequency band and modulating the data signal onto the optical signal in a second frequency band, the first frequency band being different from the second frequency band; and
transmitting the optical signal across the optical fiber to the receiver node; and
at the receiver node;
receiving the optical signal;
recovering the reference signal and the data signal from the optical signal; and
synchronizing the receiver node with the recovered reference signal;
wherein said synchronizing the receiver node comprises adjusting the data rate of the recovered data signal to match the rate of the recovered reference signal.
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Accused Products
Abstract
Attenuation caused by dispersion in an optical fiber communications system is compensated. A number of low-speed channels is to be transmitted across an optical fiber. Each low-speed channel is allocated a different frequency band for transmission. The attenuation caused by dispersion is estimated for each of the frequency bands. The power of each low-speed channel is adjusted to compensate for the estimated attenuation. The power-adjusted low-speed channels are frequency division multiplexed together to produce an electrical high-speed channel suitable for transmission across the communications system.
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Citations
75 Claims
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1. In an optical fiber communications system including a transmitter node coupled to a receiver node by an optical fiber, a method for synchronizing the receiver node with the transmitter node, the method comprising:
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at the transmitter node; generating a reference signal; synchronizing the transmitter node with the reference signal; wherein said synchronizing the transmitter node comprises adjusting the data rate of a data signal to match the rate of the reference signal; modulating the reference signal onto an optical signal in a first frequency band and modulating the data signal onto the optical signal in a second frequency band, the first frequency band being different from the second frequency band; and transmitting the optical signal across the optical fiber to the receiver node; and at the receiver node; receiving the optical signal; recovering the reference signal and the data signal from the optical signal; and synchronizing the receiver node with the recovered reference signal; wherein said synchronizing the receiver node comprises adjusting the data rate of the recovered data signal to match the rate of the recovered reference signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. An optical fiber communications system for transmitting at least two low-speed channels across the communications system, the communications system comprising:
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a transmitter node including; a local oscillator for generating a reference signal; and an FDM multiplexer coupled to the local oscillator for combining the low-speed channels with the reference signal into an electrical high-speed channel, wherein the reference signal and the low speed channels are separate signals in the electrical high-speed channel, wherein each of the low-speed channels and the reference signal is allocated a different frequency band within the electrical high-speed channel; and a receiver node coupled to the transmitter node by an optical fiber, the receiver node including; an FDM demultiplexer for recovering the reference signal from the electrical high-speed channel; a local oscillator; and electronics coupled to the local oscillator and the FDM demultiplexer for synchronizing the local oscillator with the recovered reference signal. - View Dependent Claims (12, 13, 14)
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15. A transmitter node for transmitting at least two low-speed channels across an optical fiber communications system, wherein the transmitter node comprises:
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a generator configured to generate a reference signal; a synchronizer configured to adjust a data rate of a data signal to match a rate of the reference signal; a modulator configured to modulate the reference signal onto an optical signal in a first frequency band and modulate the data signal onto the optical signal in a second frequency band, the first frequency band being different from the second frequency band; and circuitry configured to transmit the optical signal across the optical fiber. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23)
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24. A receiver node for receiving at least two low-speed channels transmitted across an optical fiber communications system, wherein the receiver node comprises:
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circuitry configured to receive an optical signal; a demodulator configured to recover a reference signal and a data signal from the optical signal, wherein the reference signal is modulated onto the optical signal in a first frequency band and the data signal is modulated onto the optical signal in a second frequency band, the first frequency band being different from the second frequency band; and a synchronizer configured to adjust a data rate of the recovered data signal to match a rate of the recovered reference signal. - View Dependent Claims (25, 26, 27, 28, 29, 30, 31, 32)
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33. An optical fiber communications system for transmitting at least two low-speed channels across the communications system, the communications system comprising:
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a transmitter node configured to; generate a reference signal; modulate the reference signal onto an optical signal in a first frequency band and modulate the data signal onto the optical signal in a second frequency band, the first frequency band being different from the second frequency band; and transmit the optical signal across the optical fiber; and a receiver node configured to; receive the optical signal; recover the reference signal and the data signal from the optical signal; and adjust a data rate of the recovered data signal to match a rate of the recovered reference signal. - View Dependent Claims (34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45)
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46. In an optical fiber communications system including a transmitter node coupled to a receiver node by an optical fiber, a method for synchronizing the receiver node with the transmitter node, the method comprising:
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at the transmitter node; generating a reference signal; modulating the reference signal onto an optical signal in a first frequency band and modulating the data signal onto the optical signal in a second frequency band, the first frequency band being different from the second frequency band; and transmitting the optical signal across the optical fiber; and at the receiver node; receiving the optical signal; recovering the reference signal and the data signal from the optical signal; and adjusting a data rate of the recovered data signal to match a rate of the recovered reference signal. - View Dependent Claims (47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58)
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59. A method for transmitting at least two low-speed channels across an optical fiber communications system, the method comprising:
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generating a reference signal; adjusting a data rate of a data signal to match a rate of the reference signal; modulating the reference signal onto an optical signal in a first frequency band and modulating the data signal onto the optical signal in a second frequency band, the first frequency band being different from the second frequency band; and transmitting the optical signal across the optical fiber. - View Dependent Claims (60, 61, 62, 63, 64, 65, 66)
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67. A method for receiving at least two low-speed channels transmitted across an optical fiber communications system, the method comprising:
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receiving the optical signal; recovering a reference signal and a data signal from the optical signal, wherein the reference signal is modulated onto the optical signal in a first frequency band and the data signal is modulated onto the optical signal in a second frequency band, the first frequency band being different from the second frequency band; and adjusting a data rate of the recovered data signal to match a rate of the recovered reference signal. - View Dependent Claims (68, 69, 70, 71, 72, 73, 74, 75)
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Specification