Fiber optic external modulator
First Claim
Patent Images
1. An optical modulator for modulating an optical carrier with an information signal comprising:
- means for splitting an optical carrier received from a first source into a plurality of portions;
means, coupled to receive a first portion of said optical carrier from said splitting means, for modulating said first portion with an information signal received from a second source;
means, coupled to receive a second portion of said carrier from said splitting means, for processing said second portion to provide an attenuating signal for use in attenuating said optical carrier; and
means, coupled to receive said attenuating signal and the modulated first portion of said optical carrier, for combining the modulated first portion with said attenuating signal to provide an intensity modulated attenuated optical carrier.
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Accused Products
Abstract
An improved external optical modulator provides reduced noise and distortion. An optical carrier to be modulated is split into a plurality of portions. A first portion of the carrier is modulated with an information signal. A second portion of the carrier is processed to provide an attenuating signal. The modulated carrier portion is combined with the attenuating signal to provide an attenuated optical carrier having improved apparent percentage modulation. In a preferred embodiment, the first carrier portion comprises a substantially greater amount of optical carrier power than the second carrier portion.
52 Citations
15 Claims
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1. An optical modulator for modulating an optical carrier with an information signal comprising:
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means for splitting an optical carrier received from a first source into a plurality of portions; means, coupled to receive a first portion of said optical carrier from said splitting means, for modulating said first portion with an information signal received from a second source; means, coupled to receive a second portion of said carrier from said splitting means, for processing said second portion to provide an attenuating signal for use in attenuating said optical carrier; and means, coupled to receive said attenuating signal and the modulated first portion of said optical carrier, for combining the modulated first portion with said attenuating signal to provide an intensity modulated attenuated optical carrier. - View Dependent Claims (2, 3, 4, 5)
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6. An external optical modulator comprising:
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first and second optical paths adapted to receive and carry first equal portions of an optical carrier; means operatively associated with said first and second paths for equally and oppositely phase modulating said carrier portions in said first and second paths, respectively; third and fourth optical paths adapted to receive and carry second equal portions of said optical carrier; biasing means operatively associated with said third and fourth paths for equally and oppositely phase shifting the carrier portions in said third and fourth paths, respectively; and means coupled to receive and combine the modulated carrier portions from said first and second paths with the phase shifted carrier portions from said third and fourth paths for providing an intensity modulated output signal. - View Dependent Claims (7, 8)
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9. A method for externally modulating an optical carrier to communicate an information signal over an optical signal distribution path, comprising the steps of:
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splitting an optical carrier to be modulated into a plurality of portions; modulating a first portion of said carrier with an information signal; processing a second portion of said carrier to provide an attenuating signal; and combining the modulated carrier portion with said attenuating signal to provide an attenuated optical carrier having improved apparent percentage modulation. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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Specification