EP0466182A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Optical communication apparatus using intensity modulation
Assignee: NEC Corp
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Filing: 1991-07-12
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Granted: —
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Expires: 2011-07-12
Abstract
Abstract A transmitter unit (100) comprises a semiconductor laser (101) as a carrier light exciting source, a biasing source (102) for providing the semiconductor laser a d.c. biasing current, an external modulator (105) for intensity-modulating an output light of the semiconductor laser according to a transmission signal and means (107; 210; 510; 701, 702, 703, 704) for causing the external modulator to output only the carrier light and either side-band light. A receiver unit (150) comprises a receiver (151) for square-law detecting the carrier light and the side-band light supplied from the transmitter unit to obtain an electric signal and a linear filter (152) for equalizing this electric signal. An optical communication apparatus capable of easily equalizing dispersion distortion caused in a transmission path (115) having a large dispersion from a light-intensity modulated light signal transmitted therethrough is constituted with such transmitter unit and such receiver unit.
Inventors
- 👤 Naoya C/O Nec Corporation Henmi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 20:50
CPC Classifications
H; H04; H04L; H04L27/00; H04L27/02; H04L27/06; H04B; H04B10/00; H04B10/25; H04B10/2507; H04B10/2513; H04B10/25137; H04B10/50; H04B10/501; H04B10/503; H04B10/505; H04B10/516; H04B10/5165; H04B10/54; H04B10/548; H04L27/04
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
143 words
An intensity modulation optical communication apparatus including a transmitter unit for producing an intensity modulated light signal based on a carrier light and a transmitting signal and a receiver unit for receiving the intensity modulated light signal and reproducing the transmitting signal therefrom, wherein said transmitter unit comprises: carrier producing means for producing the carrier light; amplitude modulation means for amplitude-modulating the carrier light with the transmitting signal to produce a double side-band signal; and transmitting means for extracting from the double side-band signal a carrier light component and either one of the side-band components and sending them to a transmission path as the intensity modulated light, and wherein the receiver unit comprises: means for producing an electric signal by detecting the intensity modulated light supplied from said transmission path; and equalizer means for equalizing the electric signal to reproduce the transmitting signal.
Claim 2
Dependent Claim
80 words
The apparatus claimed in claim 1, wherein said transmitter unit comprises: carrier light producing means for producing a carrier light according to a control signal; control signal generating means for producing said control signal by phase-shifting said transmission signal by a constant phase angle and emphasizing a high frequency component thereof; and amplitude modulation means for amplitude-modulating said carrier light according to said transmission signal to output said carrier light component and a component of either one of said side-bands.
Claim 3
Dependent Claim
90 words
The apparatus claimed in claim 2, wherein said control signal generator means comprises: a plurality of filters for dividing a band of said transmission signal to a plurality of sub-bands; a plurality of level regulator means connected to said filters, respectively, a plurality of delay means for delaying outputs of said level regulator means by an amount corresponding to said constant phase angle at center frequencies of said filters connected to said level regulator means; and adder means for adding outputs of said delay means to produce said control signal.
Claim 4
Dependent Claim
135 words
The apparatus claimed in claim 2, wherein said control signal generator means is control means comprising a plurality of filters for dividing a band of said transmission signal to a plurality of sub-bands, a plurality of level regulator means connected to said filters, respectively and first adder means for adding outputs of said level regulator means to produce said control signal and wherein said amplitude modulation means comprises a plurality of delay means connected to said plurality of filters respectively, said delay means providing delays corresponding to said constant phase angle at said center frequencies of said filter means connected to said delay means and a second adder means for adding outputs of said delay means, said amplitude modulation means amplitude-modulating said carrier light on the basis of an output of said second adder means.
Claim 5
Dependent Claim
111 words
The apparatus claimed in claim 2, wherein said control signal generation means is constituted with means for producing a periodic signal having the same frequency as said transmission rate of said transmission signal, level regulation means for regulating a level of said periodic signal and outputting a level regulated periodic signal and delay means for delaying said level regulated periodic signal by a constant delay amount to produce a control signal, and wherein said amplitude-modulation means is constituted with conversion means for converting at least a mark signal of said transmission signal into a square-low cosine wave and a modulator for amplitude-modulating said carrier light according to said square-law cosine wave.
Claim 6
Dependent Claim
15 words
The apparatus claimed in claim 5, wherein said periodic signal is a sine wave signal.
Claim 7
Dependent Claim
27 words
The apparatus claimed in claim 5 or 6, wherein said constant delay amount of said delay means is one fourth of a period of said periodic signal.
Claim 8
Dependent Claim
27 words
The apparatus claimed in claim 5 or 6, wherein said constant delay amount of said delay means is three fourth of a period of said periodic signal.
Claim 9
Dependent Claim
104 words
The apparatus claimed in claim 2, wherein said control signal generation means is constituted with means for producing a periodic signal having the same frequency as said transmission rate of said transmission signal and level regulation means for regulating a level of said periodic signal and outputting a level regulated periodic signal as said control signal, and wherein said amplitude-modulation means is constituted with conversion means for converting at least a mark signal of said transmission signal into a square-low cosine wave, delay means for delaying said square-low cosine wave and a modulator for amplitude-modulating said carrier light according to said square-low cosine wave.
Claim 10
Dependent Claim
15 words
The apparatus claimed in claim 9, wherein said periodic signal is a sine wave signal.
References Cited (Backward Citations)
No citation records indexed.
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