Patent EP0862291A2 successfully refreshed from Google Patents.
EP0862291A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Wavelength division multiplexing communication system
Assignee: NEC Corp
•
Filing: 1998-02-27
•
Granted: —
•
Expires: 2018-02-27
Abstract
Abstract In an optical transmitter, control signal generators for generating control signals on different frequencies are connected to light sources, respectively, that emit light beams with non-overlapping wavelength bands. The light beams from the light sources are modulated in intensity by the control signals, respectively. Intensity modulated signals are further modulated with input data by optical modulators and are then amplified by optical amplifiers. Amplified optical signals are multiplexed by an optical multiplexer into a multiplexed signal. The multiplexed signal is supplied to a transmission path. In the optical amplifier, a part of a wavelength division multiplexed signal amplified by an optical fiber 33 is branched by an optical branch circuit 36. A branched wavelength division multiplexed signal is converted into an electrical signal by an optical/electrical converter 37. Band-pass filters 38-1 through 38-n extract the control signals from the electrical signal. A counter 39 counts up the number of extracted control signals. An LD drive circuit 40 controls a laser diode 34 to adjust an output level of the signal to have the best value for the number of the optical signals multiplexed on the same fiber, according to the counted value.
Inventors
- 👤 Satoshi Mikami
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 00:17
CPC Classifications
H; H04; H04J; H04J14/00; H04J14/02; H04J14/0221; H04B; H04B10/00; H04B10/50; H04B10/501; H04B10/506; H04B10/564
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
85 words
A wavelength division multiplexing communication system comprising an
optical transmitter for use in multiplexing a plurality of optical signals with the transmission
spectrum divided into a number of non-overlapping wavelength bands to transmit a
multiplexed signal as a wavelength division multiplexed signal, an optical amplifier (30) for
repeat amplifying the wavelength division multiplexed signal, characterised by means
(37,38,39) for counting the number of wavelength bands present in the signal, and means
(33,35-40) for controlling the optical amplifier in response to the counted number of bands.
Claim 2
Dependent Claim
211 words
A wavelength division multiplexing communication system comprising an
optical transmitter for use in multiplexing a plurality of optical signals with the transmission
spectrum divided into a plurality of non-overlapping wavelength bands to transmit a
multiplexed signal as a wavelength division multiplexed signal; and an optical amplifier (30)
for repeat amplifying the wavelength division multiplexed signal, wherein; said optical transmitter comprises intensity modulating means (21-1 to 21-n) for
modulating intensity of the optical signals by means of control signals on different
frequencies; said optical amplifier comprising branching means (36) for branching a part of said
wavelength division multiplexed signal to produce a branched wavelength division
multiplexed signal; optical/electrical converting means (37) for converting said branched
wavelength division multiplexed signal into an electrical signal to produce a converted
electrical signal; a plurality of band-pass filters (38-1 to 38-n) adapted to pass signals
corresponding to the control signals on different frequencies from said converted electrical
signal; counting means (39) for counting the number of the signals passed through said band-pass
filters to produce a signal indicative of a counted value; and amplifying means (33 to 35, 40) for amplifying said
wavelength division multiplexed signal according to said
counted value in response to said converted electrical
signal and the signal indicative of said counted value.
Claim 3
Dependent Claim
115 words
A wavelength division multiplexing
communication system as claimed in Claim 2, wherein said
optical transmitter comprises a plurality of light
sources (22-1 to 22-n) for emitting light beams with non-overlapping
wavelength bands; a plurality of optical
modulators (23-1 to 23-n) for modulating said light beams
from the respective light sources with input data to
produce it as the optical signal; an optical multiplexer
(25) for multiplexing said optical signals supplied from
said optical modulators, and wherein a plurality of
control signal generators (21-1 to 21-n) are provided, as
said intensity modulating means, for supplying the
control signals on different frequencies to the light
sources to modulate intensity of said light beams from
said light sources.
Claim 4
Dependent Claim
140 words
A wavelength division multiplexing
communication system as claimed in Claim 2, wherein said
optical transmitter comprises a plurality of light
sources (21-1 to 21-n) for emitting light beams with non-overlapping
wavelength bands; a plurality of optical
modulators (23-1 to 23-n) for modulating said light beams
from the respective light sources with input data to
produce it as the optical signal; an optical multiplexer
(25) for multiplexing said optical signals supplied from
said optical modulators, and wherein a plurality of
intensity modulators (26-1 to 26-n) and a plurality of
control signal generators (21-1 to 21-n) are provided, as
said intensity modulating means, said intensity
modulators being provided for modulating intensity of
said light beams at an upstream of said optical
modulators and said control signal generators being
provided for supplying said control signals on different
frequencies to said intensity modulators, respectively.
Claim 5
Dependent Claim
139 words
A wavelength division multiplexing
communication system as claimed in Claim 2,wherein said
optical transmitter comprises a plurality of light
sources (22-1 to 22-n) for emitting light beams with non-overlapping
wavelength bands; a plurality of optical
modulators (26-1 to 26-n) for modulating said light beams
from the respective light sources with input data to
produce it as said optical signals; an optical
multiplexer (25) for multiplexing said optical signals
supplied from said optical modulators, and wherein a
plurality of intensity modulators (26-1 to 26-n) and a
plurality of control signal generators (21-1 to 21-n) are
provided, as said intensity modulating means, said
intensity modulators being provided for modulating
intensity of said light beams at a downstream of said
optical modulators and said control signal generators
being provided for supplying said control signals on
different frequencies to said intensity modulators,
respectively.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.