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公开(公告)号：EP0776552A1
公开(公告)日：1997-06-04
申请号：EP95927893.0
申请日：1995-08-15
CPC分类号： H04B10/07 , G01M11/3118 , G01M11/3136 , H04B10/071 , H04B10/27 , H04B10/272
摘要： In an optical transmission system incorporating a passive optical network (PON), fault detection is effected by a time domain reflectometer technique in which the system transmitter generates a sequence having statistical properties equivalent to a continuous random binary sequence. A delayed copy of the sequence is correlated with an echo of the sequence reflected from a fault, the time delay required to effect correlation giving an indication of the fault location.
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2.发明公开DUOBINARY CODING AND MODULATION TECHNIQUE FOR OPTICAL COMMUNICATION SYSTEMS 失效DUOBINÄRKODIERUNGS-和调制技术的光学控制系统新闻
公开(公告)号：EP0920731A1
公开(公告)日：1999-06-09
申请号：EP98913476.0
申请日：1998-03-25
发明人： VAZIRI, Masoud , O'SULLIVAN, Maurice, S. , TARASCHUK, Terry, W., B. , SOLHEIM, Alan, Glen , ROBERTS, Kim, Byron
CPC分类号： H04B10/5055 , H03M5/18 , H04B10/505 , H04B10/5167
摘要： A method for encoding a binary input sequence x(0,1) to obtain a duobinary output sequence y(+1,0,-1) is provided. The duobinary coding technique always provides an output bit yk =0 when the corresponding bit xk =0; bits yk alternatively assume a logical level '+1' and '-1' whenever an input bit xk-1=0 changes to xk=1, and the output bit yk maintains the logical level '+1' or '-1' whenever the corresponding bit xk maintains the logical level '1'. A coding device for encoding a binary input sequence x(0,1) to a duobinary output sequence y(+1,0,-1) is also provided, comprising a D-type flip-flop for generating a binary switch signal. A first AND circuit receives the input sequence and the switch signal, and provides a first binary sequence a(0,1), while a second AND circuit receives the input sequence and the complement of the switch signal and provides a second binary sequence b(0,1). These first and second binary sequences are applied to a summer to obtain the output sequence y(+1,0,-1). A method for differentially driving an M-Z modulator using a virtual ground level is also provided, which reduces the peak-to-peak drive voltage by a factor of two.
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3.发明公开
公开(公告)号：EP0908034A1
公开(公告)日：1999-04-14
申请号：EP96939787.0
申请日：1996-12-04
CPC分类号： H04J14/0291 , H04B10/032 , H04B10/2503 , H04B10/2972 , H04J14/0221 , H04J14/0227 , H04J14/0241 , H04J14/0279 , H04J14/0283
摘要： The invention provides a method and system for transmitting very high bit rates over an optical link, using unidirectional and bidirectional WDM technology. The 1550 nm window for optical transmission is spatially separated into two bands, 'Red' and 'Blue', and the channels in each band are selected so that respective wavelengths present a substantially equal gain tilt. A fiber amplifier designed according to spatial separation and wavelength selection of the invention is disclosed, along with multiple span WDM network topologies.
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公开(公告)号：EP0513002B1
公开(公告)日：1994-01-26
申请号：EP90917395.7
申请日：1990-11-30
IPC分类号： H01S3/133
CPC分类号： H01S5/06832
摘要： A laser diode control circuit maintains a desired average output power of the laser diode (10) by detecting (18) the optical output, amplifying (24) the detected output, and controlling a bias current (14) of the laser diode accordingly. A pilot tone (20) is combined with the detected output (18) and amplified therewith, and the amplified (24) level of the tone is detected (22) and used to control (26) a modulation current (16) for the laser diode. In one described arrangement the laser diode (10) is controlled to have a high extinction ratio with the bias current at the knee (42) of the diode's characteristic curve, and in another arrangement a lower extinction ratio is provided with the bias current above the knee (42).
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公开(公告)号：EP0513002A1
公开(公告)日：1992-11-19
申请号：EP90917395.0
申请日：1990-11-30
IPC分类号： H01S5
CPC分类号： H01S5/06832
摘要： Un circuit de commande de diode à laser assure une puissance de sortie moyenne voulue de la diode à laser (10) en détectant (18) la sortie optique, en amplifiant (24) la sortie détectée et en commandant de manière appropriée le courant de polarisation (14) de la diode à laser. Un signal pilote (20) est associé à la sortie détectée (18) et amplifié avec celle-ci, et le niveau amplifié (24) du signal est détecté (22) et utilisé pour commander (26) un courant de modulation (16) pour la diode à laser. Dans un des agencements décrits la diode à laser (10) est commandée de manière à posséder un rapport élevé d'extinction lorsque le courant de polarisation est situé au coude (42) de la courbe caractéristique de la diode, et dans un autre agencement, un rapport d'extinction inférieur est obtenu lorsque le courant de polarisation est situé au-dessus du coude (42).
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公开(公告)号：EP0890229A1
公开(公告)日：1999-01-13
申请号：EP97900522.0
申请日：1997-01-22
发明人： ROBERTS, Kim, Byron , O'SULLIVAN, Maurice, Stephen , HABEL, Richard, A. , KENNEDY, Christopher, Brendan
CPC分类号： H04B10/2912 , H04B10/07955 , H04B10/0797 , H04B10/2931 , H04B10/2971 , H04B2210/08
摘要： The invention is directed to a failure detection system and method for detecting malfunction of an optical amplifier module with one or multiple transmission channels. The failure detection system comprises means for measuring a performance parameter of the module; means for providing an expected performance parameter; and a comparator unit for receiving the performance parameter and the expected performance parameter and producing an error signal when the performance parameter substantially departs from the expected performance parameter. The system also includes a display/alarm unit for receiving the error signal and accordingly signaling failure of said module. The performance parameter is an output value of the module; a correspondence between an output value and an input value for a transmission channel; a figure of merit (FOMt=t); a set of gains (g) for all transmission channels; and the dynamic range of the amplifier module.
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7.发明公开
公开(公告)号：EP0875105A1
公开(公告)日：1998-11-04
申请号：EP96925616.0
申请日：1996-07-31
发明人： O'SULLIVAN, Maurice, Stephen , ROBERTS, Kim, Byron , HARLEY, James, St. Leger , WESLOWSKI, Jeffrey, Alan
CPC分类号： H04B10/291 , H04B10/0771 , H04B10/0777 , H04B2210/075
摘要： An optical transmission system comprises means for modulating the optical output of a laser of an optical amplifier module with a transmitted dither; means for measuring an incoming optical signal of the optical amplifier module for detecting a received dither; and means for processing the received dither and said transmitted dither for determining the ratio of the energy in the received dither to the energy in the transmitted dither. When the optical transmission system has a plurality of optical amplifiers, the optical output of each optical amplifier is modulated with a respective transmitted dither which is uncorrelated to the dithers transmitted by the other optical amplifiers in the transmission system. A method for monitoring the performance of an optical transmission system is also disclosed, the method comprising the steps of generating at an optical amplifier a transmitted dither of a known energy; measuring an incoming signal for detecting a received dither; and determining the ratio of energy in the received dither to the energy in the transmitted dither.
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