Optical communications system with wavelength division multiplexing
First Claim
1. An optical communications transmitter system comprising:
- a first light source outputting a first light beam having a first wavelength;
a second light source outputting a second light beam having a second wavelength differing from the first wavelength;
a wave division multiplexer, both the first and second light beams being coupled to input ports of the wave division multiplexer, and the wave division multiplexer having an output port, wherein the output port is coupled to an optical fiber span for transmission of an optical signal including both the first and second wavelengths;
wherein the optical signal at both the first and second wavelengths is modulated by the same RF information; and
a modulator coupled between the output port of the wavelength division multiplexer and the fiber optical span, wherein an RF signal carrying the RF information is coupled to an electrical port of the modulator.
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Accused Products
Abstract
A wavelength division multiplexer (WDM) in an optical fiber transmission system launches analog signals, for instance a multi-channel television signal. The WDM enhances signal quality by transmitting along a single fiber two different optical wavelength signals, each carrying identical RF information. This results in a 3 dB improvement in carrier to noise ratio. The WDM combines two or more wavelengths centered around for instance 1550 nm or 1310 nm. A typical difference between the two wavelengths is 3 nm. In other embodiments, more than two wavelengths are used. The receiver is for instance a single photosensitive element. The phase of the two RF signals is adjusted in the optical or RF domain to be the same upon arrival at the receiver. In other embodiments, the receiver includes two photosensitive elements, each receiving from a receiver end WDM a single wavelength. In this case, the phase adjustment may be applied at the receiver in the optical or RF domain.
174 Citations
23 Claims
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1. An optical communications transmitter system comprising:
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a first light source outputting a first light beam having a first wavelength; a second light source outputting a second light beam having a second wavelength differing from the first wavelength; a wave division multiplexer, both the first and second light beams being coupled to input ports of the wave division multiplexer, and the wave division multiplexer having an output port, wherein the output port is coupled to an optical fiber span for transmission of an optical signal including both the first and second wavelengths; wherein the optical signal at both the first and second wavelengths is modulated by the same RF information; and a modulator coupled between the output port of the wavelength division multiplexer and the fiber optical span, wherein an RF signal carrying the RF information is coupled to an electrical port of the modulator. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of transmitting RF information on a span of optical fiber, comprising:
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generating first and second light beams of differing wavelengths; wavelength division multiplexing both the first and second light beams; modulating both the first and second light beams with the same RF information; and coupling the modulated and wavelength division multiplexed first and second light beams to the span of optical fiber, wherein after multiplexing, the light beams are modulated by the RF information. - View Dependent Claims (12)
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13. An optical communications system comprising:
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a transmitter system outputting two wavelength division multiplexed optical signals, each carrying the same RF information; a span of optical fiber coupled to the transmitter system; a receiver coupled to the span of optical fiber, wherein the transmitter system comprises; a first light source outputting a first light beam having a first wavelength. a second light source outputting a second light beam having a second wavelength differing from the first wavelength; and a wavelength division multiplexer, both the first and second light beams being coupled to input ports of the wavelength division multiplexer, and the wavelength division multiplexer having an output port, wherein the output port is coupled to the optical fiber span; and a modulator coupled between the output port of the wavelength division multiplexer and the fiber optical span, wherein an RF signal carrying the RF information is coupled to an electrical port of the modulator. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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Specification