WO1987002531A1 - Systeme de communication optique et son terminal utilisateur - Google Patents

Systeme de communication optique et son terminal utilisateur Download PDF

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Publication number
WO1987002531A1
WO1987002531A1 PCT/GB1986/000618 GB8600618W WO8702531A1 WO 1987002531 A1 WO1987002531 A1 WO 1987002531A1 GB 8600618 W GB8600618 W GB 8600618W WO 8702531 A1 WO8702531 A1 WO 8702531A1
Authority
WO
WIPO (PCT)
Prior art keywords
signal
modulation
modulator
optical
transmitter
Prior art date
Application number
PCT/GB1986/000618
Other languages
English (en)
Inventor
William James Stewart
Original Assignee
Plessey Overseas Limited
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Plessey Overseas Limited filed Critical Plessey Overseas Limited
Publication of WO1987002531A1 publication Critical patent/WO1987002531A1/fr

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/25—Arrangements specific to fibre transmission
    • H04B10/2587—Arrangements specific to fibre transmission using a single light source for multiple stations

Definitions

  • a typical communications system comprises:- a transmitter terminal, usually a laser source and modulator; a fibre link for propagating modulated transmitted optical signal; and, a receiver terminal, usually including an optical detector and demodulator.
  • SUBSTITUTESHEET flow of information between users, it is conventional practice that each user is provided with both a receiver and a transmitter, the transmitter of one user being linked to the receiver of another by means of an optical fibre. Where each user generates a distinctive modulated signal, it is possible to link all users by means of a common optical fibre.
  • the system configuration there discussed is as shown in figure 1.
  • the transmission signal for this system is provided by two lasers TX ] _, TX 2 each operating at a different optical wavelength passes through a first modulator Ml and is combined with the other signal component 2 ky means of a wavelength division multiplex (WDM) multiplexer MX.
  • WDM wavelength division multiplex
  • the combined signal is then distributed to a number of users T2 via an energy splitter SR and corresponding single-fibre forward-direction links F j _.
  • the transmitted signal is demultiplexed DX and the modulated component Xj is directed to the detector of the receiver RX 2 «
  • the other signal component ⁇ 2 ⁇ - s directed to a second modulator M2 and thence returned by a further link fibre F2 and combiner CR to the receiving detector RX j _ of the transmitter terminal Tl.
  • the modulator M2 of the user operates upon carrier signal supplied not locally, but from the transmitter Tl, a remote facility. Since the number of lasers required for multi-user systems can be reduced to just the two provided at the transmitter terminal, system costs can be much reduced and problems of laser reliability and maintenance minimised. Notwithstanding, two fibre links, forward and return path, need be provided for each user.
  • the present invention is intended to provide an alternative and relatively low cost optical communications system. It is also intended to provide user terminals of less complexity and of inexpensive design.
  • an optical communications system comprising:- a transmitter including a light source; an optical fibre link interfaced to said transmitter, for propagating light signal; and, at least one user terminal remote from said transmitter, said one user terminal being interfaced to said fibre-link to receive said light signal; wherein, said one user terminal includes:- a modulator for applying a modulation to said light signal; and, signal return means, co-operative with both said modulator and said fibre link, for returning to same said fibre- link, optical signal including said applied modulation.
  • modulated signal is produced by the user using signal supplied from a remote transmitter source.
  • the user thus has no longer any need for an individua3 light light source, and in consequence the user terminal can be much simplified.
  • the transmitted signal itself also may be modulated at source.
  • the invention as embodied may thus comprise:- a transmitter, including a light source and a first modulator, for transmitting a light signal including a first modulation; an optical fibre link, interfaced to said transmitter, for propagating modulated light signal; and, at least one user terminal, remote from said transmitter, said one user terminal being interfaced to said fibre link to receive said modulated light signal; wherein, said one user terminal includes:- a second modulator for applying a second and distinguishable modulation to said modulated light signal; an optical detector, responsive to light signal including said first modulation; and, signal return means, co-operative with both said second modulator and said fibre link for returning light signal including said second modulation to said fibre link, and for passing optical signal including said first modulation to said optical detector.
  • the user terminal modulator and optical detector may be placed in series.
  • said signal return means may comprise a ref3ector located between the modulator and the detector - for example, a partially reflecting mirror or wavelength reflective mirror as may be appropriate.
  • the user terminal modulator and optical detector may be coupled in parallel. In such latter case each may be preceded by a common coupler with a reflector - eg. a mirror, located following the modulator.
  • the light signal is returned via the modulator. Since then light signal passes twice through this modulator, modulation is applied twice. For data rates considered here, and provided the transit delay between the modulator and reflector is minimal, modulation pulse broadening will be inappreciable.
  • the overall result will be an increase in the modulation depth, ie. this depth will be doubled. The resultant modulation depth is thus produced using significantly less power than would be necessary to produce the same modulation for a single pass configuration.
  • the transmitter and more than one user terminal may be connected by corresponding single optic fibres, and the user terminal interfaced to these corresponding fibres, in each case, to provide for bidirectional transmission between the transmitter and each user terminal.
  • user modulation is applied to the source modulated signal, it is important that the first and second modulations are distinguishable.
  • the source may provide light signal at two distinguishable optical wavelengths, first modulation being applied to light of one wavelength and second modulation being applied to light of the other; ii) The source may provide light signal at a unique optical wavelength, different modulation bands being adopted for first and second modulation; iii) One of the first and second modulations may be amplitude modulation whilst the other may be phase modulation; iv) The source may provide light signal having two orthogonal polarisations, first and second modulation being applied to respective polarisations; or, v) Time-division multiplexing may be adopted.
  • Modulators for phase, amplitude, and or polarisation may be for example of fibre type (see UK Patent
  • the reflector may be embodied in any of several ways. Thus it may be:- i) A mirror integrated with tr.e modulator; ii) A mirror integrated with the detector; iii) Provided by the detector itself, surface reflection being utilised; iv) Of fibre loop type; or, v) Of fibre type, with a coupler for signal extraction.
  • the detector may be of semiconductor silicon or III-V compound type and for convenience may be integrated with post-detection circuit components. Alternatively, it may be part of a coherent system. This latter is particularly desirable for the case of phase modulation.
  • a user terminal comprising essentially:- a modulator, for applying modulation to a received optical signal; an optical detector; and, signal return means, co-operative with said modulator and an optical fibre input to said user terminal for returning there to optical signal including said applied modulation.
  • FIG. 1 is a block scher'itic drawing showing the configuration of a known communications system, a system having two fibre links one for forward transmitting the other for return signal;
  • FIGS. 2 and 3 are block schematics showing two variants of a communications system embodied in accordance with the present invention
  • Figure 4 is a block schematic drawing of a preferred configuration, also embodied in accordance with the present invention.
  • Figure 5 is a plan drawing showing the detailed arrangement of the modulator, suitable for the system configuration of the preceding figure.
  • an optical communications system comprising a source terminal Tl and a user terminal T2, interconnected by means of a single optical fibre-link F.
  • a modulator M At the user terminal T2 light from the optical fibre-link F is interfaced to a modulator M and, following this modulator, light signal is passed to a receiver detector RX ia an interposed mirror member
  • the source terminal Tl includes a transmitter TX as also a receiver RX ⁇ .
  • the latter receiver RX ⁇ is arranged to receive light coupled out of the fibre-link F by means of a coupler C.
  • the light signal that is received is directed from the signal division mirror SD of the user terminal.
  • the transmitted light signal is modulated at source and further and distinguishable modulation is applied to the transmitted signal by the user modulator M.
  • the mirror SD serves to pass light signal including the first modulation to the user receiver R X2* At the same time it serves to reflect light signal including the user applied modulation. It thus affords bidirectional transmission between the -source terminal and the user.
  • each receiver RX ⁇ , RX could be preceded by a suitable filter, polariser or other modulated signal discriminating device, as appropriate, or could be tuned to detect sic _al only of the appropriate modulation, depending on implimentation.
  • a suitable filter, polariser or other modulated signal discriminating device as appropriate, or could be tuned to detect sic _al only of the appropriate modulation, depending on implimentation.
  • Light signal reflected from this mirror SD is then directed back towards the source terminal Tl and coupled to the source, receiver RX ⁇ by means of the optical coupler C.
  • a coherent detection arrangement is shown in Figure 3 a variant of this communication system.
  • a reference signal is extracted from the main fibre-link F by means of the optical coupler C and following reflection at a mirror R this reference signal is directed back to the source receiver RX ⁇ where it can be used for coherent detection of the user modulated signal.
  • This allows sensitivity gain and can, if another coupler is provided, afford discrimination against amplitude modulation in favour of phase.
  • an isolator I may be interposed between the transmitter TX and the coupler C.
  • a preferred configuration of the system is shown in figure 4. In this system a laser source TX directly modulatec at 565 Mbit/s, provides data transmission in one directiori.
  • a portion of this si ⁇ -.al is remodulated at 34 Mbit/s in a reflective electro-optic modulator M to provide the return data stream.
  • This technique demands the use of a coding format for the higher-data-rate channel that does not permit extended intervals of zero light tensity.
  • a 1.3Atm laser transmitter module TX is fusion-spliced to one port of a taper-fused fibre coupler C ⁇ with 1:1 power coupling ratio.
  • a 3.6 km length of loose-tubed standard monomode fibre was spliced to one output port of this coupler C ⁇ and to one input port of a second taper-fused coupler C .
  • One output of this coupler C was spliced to a 565 Mbit/s PINFET receiver RX 2 , and the other to a fibre polarisation controller P spliced to the reflective modulator M.
  • the modulator M shown is a titanium-diffused LiNb ⁇ 3 directional coupler employing uniform p > electrodes E of length 15 mm.
  • the input fibre F was mounted in a silicon V-groove support chip S and attached to the modulator M as shown in Fig. 5.
  • a reflector R was simply formed by gilding the polished end of a short length of fibre FF and locating this against one outport port of the modulator M.
  • the coded 34 Mbit/s signal was supplied to the modulator M at up to 12 V peak, superposed on a small DC bias voltage establishing the operating point.
  • the modulator response is sensitive to polarisation, adjustment of the pcLarisation controller P is found to be required only infrequently following initial optimisation.
  • the remodulated signal is detected by a 34 Mbit/s PINFET receiver RX j _ spliced to the first fibre coupler C j _.
  • the high-frequency content of this signal due to the original 565 Mbit/s modulation is integrated out by this receiver RX j _, leaving only the 34 Mbit/s data output B.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Optical Communication System (AREA)

Abstract

Système de communication optique dans lequel un signal porteur est produit du côté terminal d'émission (T1) du système et envoyé au côté terminal de réception (T2), où ce signal est modulé (M) et renvoyé au terminal d'émission (T1) par la même liaison par fibres (F). Dans l'agencement préféré montré dans la figure, un réflecteur (R) est disposé après le modulateur (M), et un signal traverse deux fois le modulateur (M) ce qui donne une profondeur de modulation double. Le signal d'émission lui-même peut-être modulé, et les modulations des signaux d'émission et de l'utilisateur peuvent être identifiés par une fréquence porteuse différente, ainsi que par les différences de bandes de modulation, de polarisation et des types de modulation en phases, en amplitude et/ou en fréquences.
PCT/GB1986/000618 1985-10-15 1986-10-13 Systeme de communication optique et son terminal utilisateur WO1987002531A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8525413A GB8525413D0 (en) 1985-10-15 1985-10-15 Optical communications system
GB8525413 1985-10-15

Publications (1)

Publication Number Publication Date
WO1987002531A1 true WO1987002531A1 (fr) 1987-04-23

Family

ID=10586694

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB1986/000618 WO1987002531A1 (fr) 1985-10-15 1986-10-13 Systeme de communication optique et son terminal utilisateur

Country Status (4)

Country Link
EP (1) EP0241527A1 (fr)
JP (1) JPS63501756A (fr)
GB (2) GB8525413D0 (fr)
WO (1) WO1987002531A1 (fr)

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4903337A (en) * 1988-09-09 1990-02-20 Square D Company Fiber optic transceiver
WO1990006498A2 (fr) * 1988-12-06 1990-06-14 British Telecommunications Public Limited Company Detecteur de pertes
US4956877A (en) * 1987-06-10 1990-09-11 Cherne Medical, Inc. Optical fiber reflective signal modulation system
EP0458251A2 (fr) * 1990-05-21 1991-11-27 Hughes Aircraft Company Liaison de communication à fibre optique bidirectionnelle et monochromatique
GB2245116A (en) * 1990-06-13 1991-12-18 Gen Electric Co Plc Telecommunications reflective optical links
EP0509500A2 (fr) * 1991-04-19 1992-10-21 Ascom Tech Ag Dispositif pour la transmission bidirectionelle simultanée d'informations numériques
TR26009A (tr) * 1990-05-21 1993-11-01 Hughes Aircraft Co TEK DALGA BOYLU, IKI YÖNLü OPTIK FIBER ILETISIM BAGLANTISI
EP0615358A1 (fr) * 1993-03-11 1994-09-14 AT&T Corp. Réseau optique basé sur l'interrogation à distance d'un équipement terminal
FR2718307A1 (fr) * 1994-03-29 1995-10-06 France Telecom Transmission de données full-duplex entre une station centrale et une station passive.
US5467212A (en) * 1993-06-04 1995-11-14 Huber; David R. Addressable grating modulation system for optical cable TV system
US5475519A (en) * 1992-12-03 1995-12-12 Robert Bosch Gmbh Integrated-optical circuit and head station for an integrated-optical circuit
US5600473A (en) * 1993-06-04 1997-02-04 Ciena Corporation Optical amplifier systems with add/drop multiplexing
EP0541409B1 (fr) * 1991-10-04 1998-04-01 Alcatel Système de transmission bidirectionnelle, notamment par fibre optique, avec une porteuse unique pour les deux sens de transmission
GB2386013A (en) * 2002-03-01 2003-09-03 Bookham Technology Plc Full duplex optical transceiver with remote light source for transmitter

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB8709072D0 (en) * 1987-04-15 1987-05-20 British Telecomm Transmission system
GB8713794D0 (en) * 1987-06-12 1987-07-15 British Telecomm Optical multiplexing
FR2654275B1 (fr) * 1989-11-09 1994-07-29 Dassault Electronique Procede et dispositif de transmission d'un signal electromagnetique dans une fibre optique.
GB9007974D0 (en) * 1990-04-09 1990-06-06 British Telecomm Loss detection
JPH053458A (ja) * 1990-10-26 1993-01-08 Nec Corp 光双方向伝送方法と装置
US5526155A (en) * 1993-11-12 1996-06-11 At&T Corp. High-density optical wavelength division multiplexing
EP1058457A1 (fr) * 1999-06-02 2000-12-06 Sony Corporation Dispositif de connection optique pour un cable optique et appareil de communication optique utilisant un tel dispositif
EP1612974B1 (fr) * 2004-06-28 2012-04-18 Alcatel Lucent Réseau optique passif avec multiplexage en longueur d'onde transparent pour protocole et fréquence de ligne.
US7386235B2 (en) 2004-06-28 2008-06-10 Lucent Technologies Inc. Protocol and line-rate transparent WDM passive optical network

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2513049A1 (fr) * 1981-09-15 1983-03-18 Thomson Csf Systeme de communication optique et reseau telephonique comprenant un tel systeme
FR2558025A1 (fr) * 1984-01-10 1985-07-12 Thomson Csf Systeme de liaison pour des transmissions bidirectionnelles simultanees par fibre optique

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1488253A (en) * 1974-12-19 1977-10-12 Davies D Telecommunication system
GB1540907A (en) * 1976-12-07 1979-02-21 Standard Telephones Cables Ltd System for obtaining data from a plurality of condition responsive optical devices
GB2019561B (en) * 1978-04-20 1982-09-02 Davies D E N Telecommunication systems
GB2083311B (en) * 1980-09-08 1984-04-11 Bicc Ltd Telecommunication systems
US4545253A (en) * 1983-08-29 1985-10-08 Exxon Production Research Co. Fiber optical modulator and data multiplexer
SE458160B (sv) * 1984-08-09 1989-02-27 Daimler Benz Ag Foerfarande foer fiberoptisk spektralkodad oeverfoeri ng av maetvaerden och anordningar foer utoevande av foerfarandet

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2513049A1 (fr) * 1981-09-15 1983-03-18 Thomson Csf Systeme de communication optique et reseau telephonique comprenant un tel systeme
FR2558025A1 (fr) * 1984-01-10 1985-07-12 Thomson Csf Systeme de liaison pour des transmissions bidirectionnelles simultanees par fibre optique

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4956877A (en) * 1987-06-10 1990-09-11 Cherne Medical, Inc. Optical fiber reflective signal modulation system
US4903337A (en) * 1988-09-09 1990-02-20 Square D Company Fiber optic transceiver
AU617913B2 (en) * 1988-12-06 1991-12-05 British Telecommunications Public Limited Company Loss detection
WO1990006498A2 (fr) * 1988-12-06 1990-06-14 British Telecommunications Public Limited Company Detecteur de pertes
WO1990006498A3 (fr) * 1988-12-06 1990-09-07 British Telecomm Detecteur de pertes
EP0458251A3 (en) * 1990-05-21 1992-11-04 Hughes Aircraft Company Single wavelength bidirectional optical fiber communication link
EP0458251A2 (fr) * 1990-05-21 1991-11-27 Hughes Aircraft Company Liaison de communication à fibre optique bidirectionnelle et monochromatique
TR26009A (tr) * 1990-05-21 1993-11-01 Hughes Aircraft Co TEK DALGA BOYLU, IKI YÖNLü OPTIK FIBER ILETISIM BAGLANTISI
US5317440A (en) * 1990-05-21 1994-05-31 Hughes Aircraft Company Single wavelength bidirectional optical fiber communication link
GB2245116A (en) * 1990-06-13 1991-12-18 Gen Electric Co Plc Telecommunications reflective optical links
EP0509500A2 (fr) * 1991-04-19 1992-10-21 Ascom Tech Ag Dispositif pour la transmission bidirectionelle simultanée d'informations numériques
EP0509500A3 (en) * 1991-04-19 1993-04-21 Ascom Tech Ag Device for bidirectional simultaneous transmission of digital information
EP0541409B1 (fr) * 1991-10-04 1998-04-01 Alcatel Système de transmission bidirectionnelle, notamment par fibre optique, avec une porteuse unique pour les deux sens de transmission
US5475519A (en) * 1992-12-03 1995-12-12 Robert Bosch Gmbh Integrated-optical circuit and head station for an integrated-optical circuit
EP0615358A1 (fr) * 1993-03-11 1994-09-14 AT&T Corp. Réseau optique basé sur l'interrogation à distance d'un équipement terminal
US5467212A (en) * 1993-06-04 1995-11-14 Huber; David R. Addressable grating modulation system for optical cable TV system
US5600473A (en) * 1993-06-04 1997-02-04 Ciena Corporation Optical amplifier systems with add/drop multiplexing
FR2718307A1 (fr) * 1994-03-29 1995-10-06 France Telecom Transmission de données full-duplex entre une station centrale et une station passive.
GB2386013A (en) * 2002-03-01 2003-09-03 Bookham Technology Plc Full duplex optical transceiver with remote light source for transmitter

Also Published As

Publication number Publication date
GB8525413D0 (en) 1985-11-20
GB8624510D0 (en) 1986-11-19
GB2181921A (en) 1987-04-29
JPS63501756A (ja) 1988-07-14
EP0241527A1 (fr) 1987-10-21

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