Patent JPS5872634A successfully refreshed from Google Patents.
EP0475376A2
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EP
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Apparatus and method for linearizing the operation of an external optical modulator
Assignee: Arris Technology Inc
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Filing: 1991-09-11
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Granted: —
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Expires: 2011-09-11
Abstract
Abstract A modulating signal is predistorted to linearize the output of an optical intensity modulator. The modulating signal is split into first and second paths. In the first path, the signal is phase shifted. In the second path, distortion components are introduced. The phase shifted signal from the first path is then combined with the distorted signal from the second path to provide a predistorted signal for use in modulating a light source. The distortion generator can comprise a diode pair coupled with opposite polarities in parallel. Both diodes are forward biased, and the pair is coupled in series with the input signal to provide the desired predistortion. <IMAGE>
Inventors
- 👤 Yudhi Trisno
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-04 19:27
CPC Classifications
H; H03; H03F; H03F1/00; H03F1/32; H03F1/3241; H03F1/3252; H03F1/3276; H04; H04B; H04B10/00; H04B10/50; H04B10/58; H04B10/588
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
88 words
Apparatus for providing a predistorted signal to linearize an optical intensity modulator comprising: means for splitting an input signal into first and second paths; phase shift means coupled to said first path for shifting the input signal phase; distortion generator means coupled to said second path for introducting distortion components into said input signal; and means for combining the phase shifted input signal from said first path with the distorted input signal from said second path to provide a predistorted signal for use in modulating a light source.
Claim 2
Dependent Claim
57 words
Apparatus in accordance with claim 1 wherein said distortion generator means comprise: a diode pair coupled with opposite polarities in parallel; a first current source for forward biasing one of said diodes; a second current source for forward biasing the other of said diodes; and means for coupling said diode pair in series with said second path.
Claim 3
Dependent Claim
21 words
Apparatus in accordance with claim 1 or 2 wherein said phase shift means is adjustable to provide a desired phase delay.
Claim 4
Dependent Claim
24 words
Apparatus in accordance with any one of claims 1 to 3 further comprising: a variable gain amplifier coupled to adjustably amplify said distortion components.
Claim 5
Dependent Claim
26 words
Apparatus in accordance with claim 4 wherein said variable gain amplifier is coupled in said second path between said distortion generator means and said combining means.
Claim 6
Dependent Claim
21 words
Apparatus in accordance with claim 4 or 5 further comprising: an attenuator coupled between said distortion generator means and said amplifier.
Claim 7
Dependent Claim
28 words
Apparatus in accordance with any one of claims 4 to 6 wherein said variable gain amplifier is coupled to amplify the predistorted signal provided by said combining means.
Claim 8
Dependent Claim
34 words
Apparatus in accordance with any of the predeeding claims wherein said combining means substracts the phase shifted input signal from the distorted input signal to provide a predistorted signal comprising primarily said distortion components.
Claim 9
Dependent Claim
34 words
Apparatus in accordance with any of the preceeding claims further comprising: means for summing said input signal with the distortion components from the combinging means to provide a modulation signal for said light source.
Claim 10
Dependent Claim
22 words
Apparatus in accordance with claim 9 further comprising: amplifier means for amplifying said input signal prior to summation with said distortion components.
Claim 11
Dependent Claim
18 words
Apparatus in accordance with any of the preceeding claims wherein said light source is a solid state laser.
Claim 12
Dependent Claim
24 words
Apparatus in accordance with claim 11 wherein said predistorted signal is coupled to a Mach Zehnder modulator for modulating an output of said laser.
Claim 13
Dependent Claim
19 words
Apparatus in accordance with any of the preceeding claims wherein said distortion generator means provie odd order distortion components.
Claim 14
Dependent Claim
92 words
Apparatus for providing a predistorted signal to linearize an optical intensity modulator comprising: means for distorting an optical modulator modulation signal with distortion components similar to but opposite in polarity than distortion components introduced by said modulator; amplifier means coupled to an output of said distorting means for amplifying said distortion components; means for adjusting the gain of said amplifier to provide said distortion components at a level necessary to linearize the output of said modulator; and means for coupling the amplified distortion components to a modulating signal input of said modulator.
Claim 15
Dependent Claim
42 words
Apparatus in accordance with claim 14 wherein said distortion means comprise: a pair of diodes coupled with opposite polarities in parallel; means for forward biasing each of said diodes; and means for coupling said diode pair in series with said modulation signal.
Claim 16
Dependent Claim
47 words
Apparatus in accordance with claim 14 or 15 further comprising: means for adjustably shifting the phase of said modulation signal to compensate for a phase shift introduced by said modulator; and means for coupling the phase shifted modulation signal to said modulating signal input of the modulator.
Claim 17
Independent Claim
82 words
A method for linearizing the output of an external analog optical modulator comprising the steps of: providing a modulating signal for use in modulating an external optical modulator; adjusting the phase of said modulating signal to compensate for a phase shift introduced by said modulator; predistorting said modulation signal with odd order distortion components similar to but opposite in polarity than distortion components introduced by said modulator; and coupling said predistorted, phase shifted signal to a modulation signal input of said modulator.
Claim 18
Dependent Claim
104 words
Apparatus for providing a predistorted signal to linearize an optical intensity modulator comprising: means for splitting an input signal into first and second paths; distortion generator means coupled to said second path for introducing distortion components into said input signal; and phase shift means coupled to one of said paths for shifting the phase of said input signal in said first path with respect to said distorted input signal in said second path; means for combining the input signal from said first path with the distorted input signal from said second path to provide a predistorted signal for use in modulating a light source.
References Cited (Backward Citations)
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