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71. 发明专利

JP2000341215A OPTICAL TRANSMISSION LINE 失效
公开(公告)号：JP2000341215A
公开(公告)日：2000-12-08
申请号：JP15164799
申请日：1999-05-31
申请人： NIPPON TELEGRAPH & TELEPHONE
发明人： YONENAGA KAZUSHIGE , HIRANO AKIRA , KUWABARA SHOICHIRO , MIYAMOTO YUTAKA , TOBA HIROSHI
IPC分类号： G02B6/00 , H04B10/2507 , H04B10/2513 , H04B10/02 , H04B10/18
摘要： PROBLEM TO BE SOLVED: To suppress variation in wavelength dispersion with ambient temperature through simple constitution and to reduce deterioration in transmission characteristics by constituting a transmission line by providing in series optical fibers which have positive and negative variations in wavelength dispersion value with the ambient temperature in a transmission signal band. SOLUTION: An optical fiber cable 1 constituting each linear repeating section is so set that the mean wavelength dispersion value of each linear repeating section is always within dispersion tolerance in an ambient temperature variation range by connecting in series an optical fiber A which increases in the wavelength dispersed value corresponding to an arbitrary wavelength in the transmission signal band with the ambient temperature and an optical fiber B which decreases, i.e., two kinds of optical fibers A and B having positive and negative temperature differentiation coefficients of wavelength dispersed values. Consequently, the temperature variation of the mean wavelength dispersed values in each linear section can be suppressed below a variation quantity affecting deterioration of a transmission signal and a high-speed large-capacity optical transmission system of simple constitution can be structured without using a wavelength dispersion control mechanism.

72. 发明专利

JP2000156665A OPTICAL TRANSMISSION METHOD, OPTICAL TRANSMITTER AND OPTICAL TRANSMISSION SYSTEM 失效
公开(公告)号：JP2000156665A
公开(公告)日：2000-06-06
申请号：JP32957398
申请日：1998-11-19
申请人： NIPPON TELEGRAPH & TELEPHONE
发明人： MATSUURA AKIHIKO , YONENAGA KAZUSHIGE , MIYAMOTO YUTAKA
IPC分类号： G02F1/01 , H04B10/2513 , H04B10/516 , H04B10/54 , H04B10/58 , H04B10/61 , H04L25/497 , H04B10/152 , H04B10/04 , H04B10/06 , H04B10/142
摘要： PROBLEM TO BE SOLVED: To reduce the influence of waveform distortion of a modulator drive signal due to the low band cutoff characteristic of a modulator drive circuit and to raise the limit for the distance of transmission by converting the binary data signal into a deformed duo-bianry signal that is suppressed to a DC component and using this duo-binary signal as the modulator drive signal to drive a light intensity modulator. SOLUTION: A binary data signal is converted into a deformed duo-binary signal that is suppressed to a DC component and used as a modulator drive signal which drives a light intensity modulator. A deformed duo-binary coding circuit 10 converts 0 and 1 of the binary data signal into 0 and +1 or -1 respectively and also converts the binary data signal into a ternary deformed duo-binary signal of -1, 0 and +1 whose +1 and -1 are never continuous over 2 bits respectively. The ternary deformed duo-binary signal is turned into a non-inverse deformed duo-binary signal and an inverse deformed duo-binary signal whose phases are inverted to each other by an inverter circuit 75 and then applied to the electrodes 84a and 84b of an MZ type light intensity modulator 80 via the modulator drive circuits 76a and 76b respectively.

73. 发明专利

JP2000151518A OPTICAL TRANSMISSION METHOD AND OPTICAL TRANSMISSION SYSTEM 失效
公开(公告)号：JP2000151518A
公开(公告)日：2000-05-30
申请号：JP32060398
申请日：1998-11-11
申请人： NIPPON TELEGRAPH & TELEPHONE
发明人： MATSUURA AKIHIKO , YONENAGA KAZUSHIGE , MIYAMOTO YUTAKA
IPC分类号： H04B10/516 , H04B10/07 , H04B10/54 , H04B10/548 , H04B10/61 , H04L7/02 , H04B10/152 , H04B10/04 , H04B10/06 , H04B10/142
摘要： PROBLEM TO BE SOLVED: To more stably reproduce a clock signal on a reception side and to highly reliably receive each data bit to be transmitted by generating an optical signal phase modulated in accordance with a clock signal phase synchronized with transmission data in accordance with transmission data on an optical transmission device side and reproducing the clock signal based on a change in a phase of the optical signal received on an optical receiver side. SOLUTION: An optical transmitter 10 modulates an intensity of an optical carrier wave 41 by an intensity modulator 11 in accordance with a level of a data signal 42 and modulates a phase of an optical carrier wave 44 which is intensity modulated by a phase modulator 12 in accordance with a level of a clock signal 43. An optical signal 45 is transmitted to an optical receiver 30 through an optical transmission line 20. The optical receiver 30 reproduces a clock signal 52 by an optical frequency discriminator 34, an optical/electric(O/ E) converter 35 and a band pass filter 36 on the basis of a phase modulation component of the optical signal 45 to be transmitted. Thus, it is possible to reproduce a clock signal 52 whose frequency is stable almost irrespective of a bit pattern of the data signal 42.

74. 发明专利

JP2000115077A AUTOMATIC WAVE-LENGTH DISTRIBUTION/EQUALIZATION OPTICAL TRANSMISSION SYSTEM 失效
公开(公告)号：JP2000115077A
公开(公告)日：2000-04-21
申请号：JP28462698
申请日：1998-10-06
申请人： NIPPON TELEGRAPH & TELEPHONE
发明人： KUWABARA SHOICHIRO , SANO AKIHIDE , YONENAGA KAZUSHIGE , MIYAMOTO YUTAKA , YONEYAMA MIKIO , TOBA HIROSHI
IPC分类号： H04B3/04 , H04B10/07 , H04B10/2507 , H04B10/2513 , H04B10/29 , H04B10/293 , H04B10/299 , H04B10/02 , H04B10/16 , H04B10/17 , H04B10/18
摘要： PROBLEM TO BE SOLVED: To obtain an automatic wave-length distribution/equalization optical transmission system by which the reproduction relay section of a high speed optical transmission system is made to be long in distance by equalizing the wave length distribution of a linear relay section by means of a linear repeater and equalizing the wave length distribution of the reproduction relay section in a receiving device and the receiving part of a reproduction repeater. SOLUTION: The linear repeater 20 is provided with a variable distribution equalizer 21 changing a distribution quantity and equalizing a distribution, an optical brancher 22, an optical amplifier 23 and a control circuit 24 controlling the distribution quantity to be set in the variable distribution equalizer 21 in accordance with the wave length distribution of the linear relay section. The receiving device (the receiving part of the reproduction repeater) 30 is provided with the optical amplifier 31, the variable distribution equalizer 32 changing the distribution quantity and equalizing the distribution and the control circuit 37 controlling the distribution quantity to be set in the variable distribution equalizer 32 in accordance with the wave length distribution of the reproduction relay section. Then the wave length distribution of the linear relay section is equalized in the linear repeater 20 and the wave length distribution of the reproduction relay section is equalized in the receiving device (the receiving part of the reproduction repeater) 30.

75. 发明专利

JPH10246874A OPTICAL MODULATOR CONTROL CIRCUIT 失效
公开(公告)号：JPH10246874A
公开(公告)日：1998-09-14
申请号：JP4933197
申请日：1997-03-04
申请人： NIPPON TELEGRAPH & TELEPHONE , N T T ELECTRON KK
发明人： AIZAWA SHIGEKI , MIYAO HIROSHI , YONENAGA KAZUSHIGE , TAKACHIO NOBORU , MIYAMOTO YUTAKA , KUWANO SHIGERU
IPC分类号： G02F1/03 , G02F1/01
摘要： PROBLEM TO BE SOLVED: To control the bias voltage of an optical modulator without being affected by an intensity-modulated component having a mean value of the finite band of an input signal and the finite band of the optical modulator. SOLUTION: A low-frequency signal outputted from a low-frequency generating means 11 is superposed on the bias voltage of an MZ type external modulator 32 through an adding means 13. The output light signal of the MZ type external modulator 32 is converted by a photoelectric converting means 13 into an electric signal. A DC and low-frequency removing means 14 removes a DC component and the low-frequency component of a low-frequency signal from this electric signal to detect only the amplitude-modulated signal component of the low-frequency signal. An envelope detecting means 15 detects the envelope of the output signal of the DC and low-frequency removing means 14. A synchronous detecting means 16 compares the phase of the output signal of the envelope detecting means 15 with that of the low-frequency signal. An integrating means 17 integrates the output signal of the synchronous detecting means 16 and corrects a bias voltage applied to the MZ external modulator 32 through an adding means 12.

76. 发明专利

JPH1022556A LIGHT GAIN CONTROL TYPE OF OPTICAL AMPLIFIER 失效
公开(公告)号：JPH1022556A
公开(公告)日：1998-01-23
申请号：JP17387196
申请日：1996-07-03
申请人： NIPPON TELEGRAPH & TELEPHONE
发明人： KUWABARA SHOICHIRO , KATAOKA TOMOYOSHI , MIYAMOTO YUTAKA
IPC分类号： H01S3/10 , H01S3/06 , H01S3/067 , H04B10/07 , H04B10/2507 , H04B10/27 , H04B10/29 , H04B10/293 , H04B10/564 , H04B10/572 , H04B10/02 , H04B10/04 , H04B10/06 , H04B10/08 , H04B10/14
摘要： PROBLEM TO BE SOLVED: To oppress even the light surge by very short instantaneous break by equipping this light amplifier with a gain control light source, which outputs a gain control light whose center wavelength is in the gain band of a rare earth doped optical fiber, and a light composing means which inputs the gain control light into the rare earth doped optical fiber. SOLUTION: An input light signal and an excitation light outputted from an excitation light source 1 are composed into united waveform by a light composing means 2, and it is inputted into a rare earth doped optical fiber 3. The output light of the rare earth doped optical fiber 3 is outputted through a light wave uniting means 4. Moreover, the gain control light outputted from a gain control light source 5 is inputted from the output side of the rare earth doped optical fiber 3 through the light wave uniting means 4. The gain control light outputted from the gain control light source 5 is always inputted into the rare earth doped optical fiber 3. The center wavelength of the gain control light set within the gain band of the rare earth doped optical fiber 3, and even if instantaneous break of about one millisecond occurs in the input light signal, an optical fiber amplifier operates with the gain saturation range, and does not bring about light surge.

77. 发明专利

JPH09162816A SYSTEM MARGIN MEASURING DEVICE 失效
公开(公告)号：JPH09162816A
公开(公告)日：1997-06-20
申请号：JP31871495
申请日：1995-12-07
申请人： NIPPON TELEGRAPH & TELEPHONE , NTT ELECTRONIC TECH
发明人： TAMAKI NORIO , HAGA KAZUO , MIYAMOTO YUTAKA
IPC分类号： H04B10/07 , H04B10/077 , H04B17/40 , H04B17/02 , H04B10/08
摘要： PROBLEM TO BE SOLVED: To measure the system margin of a two-way transmission/reception circuit with simple constitution by providing an attenuator giving a loss to inter-symbol interference light and a means for overlapping inter-symbol interference light to which the prescribed loss is given with two-way main signal light. SOLUTION: At the time of conducting an outgoing signal test, for example, a transmitter 21-1 outputs an outgoing signal whose intensity is modulated by a signal given from a pulse pattern generator 15-1. The optical power of the outgoing signal is set by adjusting an attenuator 23-1. An attenuator 23-3 is adjusted and the optical power of inter-symbol interference light is changed. The inter-symbol interference light is overlapped with the outgoing signal through an optical switch 13-1 and a photocoupler 24-1, and inter-symbol interference quantity in a receiver 25-1 is set. An error rate measuring unit 16-1 connected to the receiver 25-1 detects a code error rate corresponding to inter- symbol interference quantity which is set by the attenuators 23-1 and 23-3 and measures the system margin in the outgoing direction.

78. 发明专利

JPH098741A OPTICAL CLOCK EXTRACTING CIRCUIT 失效
公开(公告)号：JPH098741A
公开(公告)日：1997-01-10
申请号：JP15052795
申请日：1995-06-16
申请人： NIPPON TELEGRAPH & TELEPHONE
发明人： TSUDA HIROYUKI , MIYAMOTO YUTAKA , KATAOKA TOMOYOSHI , HAGIMOTO KAZUO
IPC分类号： H04B10/40 , H04B10/50 , H04B10/508 , H04B10/524 , H04B10/54 , H04B10/556 , H04B10/58 , H04B10/60 , H04B10/67 , H04B10/69 , H04B10/28 , H04B10/00 , H04B10/02 , H04B10/04 , H04B10/06 , H04B10/14 , H04B10/26
摘要： PURPOSE: To stably generate an optical clock by extracting a clock frequency component from an optical signal at an ultrahigh speed by converting an optical signal to an electric signal and efficiently driving a mode locked laser. CONSTITUTION: A mode locked laser 10 is constituted by arranging a gain medium 13 and a mode lock modulator 14 inside a Fabry-Pe'rot resonator composed of two confronting mirrors 11 and 12. The optical signal is converted to the electric signal by an optic/electric converter 20 and inputted through an impedance matching circuit 30 to the mode lock modulator 14 of the mode locked laser 10. Thus, the optical clock is generated at the frequency pulled into the clock frequency of the electric signal. Since the dependency of the optic/electric converter 20 onto the polarization and wavelength of incident light is reduced for such an optical clock extracting circuit, even when generating the optical clock, the dependency on the polarization and wavelength of incident light can be reduced.

79. 发明专利

JPH04248504A OPTICAL TRANSMITTER 失效
公开(公告)号：JPH04248504A
公开(公告)日：1992-09-04
申请号：JP3561991
申请日：1991-02-04
申请人： NIPPON TELEGRAPH & TELEPHONE
发明人： HAGIMOTO KAZUO , MIYAMOTO YUTAKA
IPC分类号： G02B6/00 , G02F1/35 , G02F2/00 , H01S3/06 , H01S3/067 , H01S3/10 , H04B10/2507 , H04B10/2513
摘要： PURPOSE:To obtain constitution wherein the loss of a dispersed medium causes no deterioration in reception sensitivity while adding the dispersed medium which compensates the dispersion of a transmission line. CONSTITUTION:A receiver consisting of an optical amplifier OA and an O/E conversion part has its S/N as a receiver determined by an initial-stage optical amplifier OA and has higher sensitivity than reception by only the O/E. Further the level itself of an optical signal after optical amplification is not S/N- sensitive. For the purpose, the output level of the OA is set much higher than the reception sensitivity of the 0/E and then even when the dispersed medium is interposed between the OA and OE, the dispersion can be compensated without any influence upon the reception sensitivity.

80. 发明专利

JPH036907A BROAD BAND DC AMPLIFIER 失效
公开(公告)号：JPH036907A
公开(公告)日：1991-01-14
申请号：JP14140589
申请日：1989-06-02
申请人： NIPPON TELEGRAPH & TELEPHONE
发明人： MIYAMOTO YUTAKA , MIYAGAWA YUZO , HAGIMOTO KAZUO
IPC分类号： H03F1/48 , H03F3/345 , H03F3/347
摘要： PURPOSE:To reduce the signal loss due to a diode substantially in the vicinity of the upper limit of the frequency band of an amplifier and to expand the frequency band width by connecting a small capacitance capacitor to the diode acting like a level shift circuit inserted in the path of an output signal. CONSTITUTION:The amplifier consists of a 1st amplifier circuit comprising a field effect transistor(TR) Q1 whose gate connects to an input terminal I, whose source connects to a common potential, and whose drain acts like an output electrode, and a 2nd amplifier circuit comprising a field effect TR Q2 whose gate is connected directly to an output electrode of the 1st amplifier circuit and connecting to the common level via a source level shift circuit, and the level shift circuit includes a diode D connecting forward to a DC bias level. A small capacitance capacitor C connects in parallel with the diode D. The capacitance of the capacitor C is selected to be equal to or less than the impedance of the diode D at a frequency near the upper limit of the amplification band of the 1st and 2nd amplifier circuits.

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