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11. 发明专利

JPS63224428A METHOD AND DEVICE FOR POLARIZATION DIVERSITY OPTICAL RECEPTION 失效
公开(公告)号：JPS63224428A
公开(公告)日：1988-09-19
申请号：JP5651087
申请日：1987-03-13
申请人： HITACHI LTD
发明人： TSUSHIMA HIDEAKI , MAEDA MINORU
IPC分类号： H04B10/58 , H04B10/03 , H04B10/532 , H04B10/556 , H04L27/22
摘要： PURPOSE:To enable to receive a PSK optical signal, to heighten sensitivity, and to simplify the constitution of an optimum threshold value setting circuit, by adding two intermediate frequency signals obtained by heterodyne-detecting two polarized components crossing orthogonally of an optical signal after delaying and detecting them respectively. CONSTITUTION:The intermediate frequency signals 3X and 3Y obtained by applying the heterodyne light detection of the two polarized components crossing orthogonally of the optical signal become inputs to delay detectors 1x and 1y respectively. The intermediate frequency signal 3X is branched to two signals 7x1 and 7x2 by a branching filter 6x. Next, the signal 7x2 receives appropriate delay by a delay line 8x. Therefore, a delay time difference (tau) exists between the signals 7x1 and 7x2 to be inputted to a multiplier 9x. A signal 10x outputted from the multiplier 9x is low-pass-filtered at a low-pass filter 11x, then, it becomes a signal 4x. The same operation is applied on the intermediate frequency signal 3Y, then, a signal 4y can be obtained. The signals 4x and 4y are added at an adder 2, and a signal 5 is outputted. The signal 5 does not depend on the polarized state of the optical signal. Also, the above operation can be realized even by removing a low-pass filter 11 from the delay detector, but, in this case, low-pass filtering is performed after adding the signals 10x and 10y.

12. 发明专利

JPS6354032A COHERENT LIGHT TRANSMISSION SYSTEM 失效
公开(公告)号：JPS6354032A
公开(公告)日：1988-03-08
申请号：JP19713186
申请日：1986-08-25
申请人： HITACHI LTD
发明人： IMOTO KATSUYUKI , TAKASE MASAHIKO , TSUSHIMA HIDEAKI , SANO HIROHISA , TAKASAKI YOSHITAKA , MAEDA MINORU
IPC分类号： G02B6/00 , G02F2/00 , H04B10/00 , H04J14/00 , H04J14/02
摘要： PURPOSE:To attain bidirectional optical communication with a simple constitution without special temperature control by inputting both part of an optical oscillation output of its own station and an optical signal from an opposite station to a photodetector so as to feed back it to an optical oscillator, thereby making the frequency constant. CONSTITUTION:The optical signal of an optical oscillator 11 of a station 24 is branched by a halfmirror 18, one is modulated by the information signal I1 of an external optical modulator 15, made incident on the optical multiplexer/ demultiplexer 20-2 of a station 25 and reflected and inputted to a photodetector 14 via an optical multiplexing/demultiplexing device 21-2. A part of the optical signal of an optical oscillator 12 is inputted to the photodetector 14 via a halfmirror 19 and the device 21-2. The signal of a difference frequency component being the output of the photodetector 14 is given to an optical oscillator 12 to keep the difference frequency constant by a feedback circuit 23. Similarly, in the station 24 the signal of the difference frequency component is inputted to a feedback circuit 22 and its output is given to the optical oscillator 11.

13. 发明专利

JP2003224872A OPTICAL SWITCHING APPARATUS, OPTICAL TRANSMISSION SYSTEM, AND METHOD FOR SETTING OPTICAL SIGNAL PATH 审中-公开
公开(公告)号：JP2003224872A
公开(公告)日：2003-08-08
申请号：JP2002020881
申请日：2002-01-30
申请人： HITACHI LTD
发明人： KAKIZAKI JUN , TSUSHIMA HIDEAKI , KITAJIMA SHIGEKI , FUKASHIRO YASUYUKI , MORI TAKASHI
IPC分类号： H04B10/03 , H04B10/032 , H04B10/079 , H04B10/27 , H04B10/291 , H04J14/02 , H04Q3/52 , H04Q11/00 , H04B10/02
摘要： PROBLEM TO BE SOLVED: To solve a problem of a conventional switching apparatus employing optical switches that cannot have discriminated a cause to signal interruption as to whether it results from a faulty optical switch or from switching because interruption of an output optical signal is caused at path switching and a post- stage performance monitor section may detect an alarm of signal interruption because of a long time required for switching in the case of particularly a mechanical type optical switch. SOLUTION: In the optical switching apparatus where optical switches are placed in redundancy, operating modes are classified into a path switching mode, an autonomous redundant switching mode and a forced redundant switching mode, the modes are not simultaneously executed, and proper mask processing is applied to each switching operation. Thus, unnecessary alarming at each switching and malfunction attendant thereon can be prevented. COPYRIGHT: (C)2003,JPO

14. 发明专利

JP2001339344A OPTICAL SIGNAL CHANGEOVER DEVICE 失效
公开(公告)号：JP2001339344A
公开(公告)日：2001-12-07
申请号：JP2000157922
申请日：2000-05-29
申请人： HITACHI LTD , HITACHI COMMUNICATION SYSTEM
发明人： HAYASHI YUKIO , KAKIZAKI JUN , TSUSHIMA HIDEAKI , KUWANO SHINICHI
IPC分类号： H04B10/03 , H04B3/46 , H04B3/48 , H04B10/032 , H04B10/07 , H04B10/075 , H04B10/2507 , H04B10/27 , H04B10/29 , H04B17/00 , H04L12/00 , H04Q11/00 , H04B10/02 , H04B10/08 , H04L12/28
摘要： PROBLEM TO BE SOLVED: To attain common use of a hardware unit in 1+1 and 1:1 switch configurations. SOLUTION: Variable branch ratio photocouplers 3-0, 6-0 have 2-input 2-output ports and drive circuit sections 4-1, 7-1 apply variable control to the branch ratio of an input light. In the optical 1+1 switch configuration, the branch ratio of the branch ratio variable photocoupler 3-0 is controlled to 50%:50%. The variable branch ratio photocoupler 6-0 controls the branch ratio to be 100%:0% or 0%:100%. In the optical 1:1 configuration, the branch ratio of the variable branch ratio photocouplers 3-0, 6-0 is controlled to be 100%:0% or 0%:100%. When a performance monitor section (0) 9-0 detects signal deterioration or signal interruption or the like, a system control section 1-0 transmits an instruction signal and control circuit sections 20-0, 21-0 output a control signal to control the branch ratio of the variable branch ratio photocouplers 3-0, 6-0. The branch ratio of the variable branch ratio photocouplers 3-0, 6-0 is gradually controlled.

15. 发明专利

JP2001007829A OPTICAL MONITOR CHANNEL TRANSFER DEVICE 失效
公开(公告)号：JP2001007829A
公开(公告)日：2001-01-12
申请号：JP17275999
申请日：1999-06-18
申请人： HITACHI LTD , NIPPON TELEGRAPH & TELEPHONE
发明人： TSUSHIMA HIDEAKI , NUNOKAWA HISAYUKI , KUWANO SHIGERU , SHIMANO KATSUHIRO , JINNO MASAHIKO
IPC分类号： H04B10/07 , H04B10/032 , H04B10/077 , H04B10/275 , H04B10/291 , H04J3/00 , H04L12/42 , H04L12/437 , H04B10/08
摘要： PROBLEM TO BE SOLVED: To provide an optical monitor channel transfer device that can transfer management information at a low cost between basic devices of an optical transmission network such as an optical branching insertion device and a repeater or the like. SOLUTION: An optical monitor channel transfer device 1 is provided with a optical reception circuit 4 that receives an optical monitor channel optical signal sent from an upstream device to obtain a optical monitor channel signal, a circuit 5 that separates an overhead part from the optical monitor channel signal, a processing circuit 6 that executes write/read of the management information of an optical transmission section and an optical multiplex section to/ from the overhead part, a circuit 7 that inserts the overhead part outputted from the processing circuit 6 to the optical monitor channel signal, and an optical transmission circuit 8 that converts the optical monitor channel signal outputted from the circuit 7 into an optical monitor channel signal of other wavelength than that of a main signal and transmits the converted signal to a downstream device.

16. 发明专利

JP2000019471A OPTICAL POWER ADJUSTING DEVICE, LIGHT TRANSMISSION DEVICE, AND LIGHT TRANSMISSION SYSTEM USING THE SAME 失效
公开(公告)号：JP2000019471A
公开(公告)日：2000-01-21
申请号：JP18714398
申请日：1998-07-02
申请人： HITACHI LTD , HITACHI COMMUNICATION SYSTEM
发明人： HAYASHI YUKIO , FUKASHIRO YASUYUKI , TSUSHIMA HIDEAKI , KUWANO SHINICHI
IPC分类号： G02F1/01
摘要： PROBLEM TO BE SOLVED: To provide an optical power adjusting device which is suitable for miniaturization and integration and is capable of automatic control of attenuation quantity. SOLUTION: The optical power adjusting device 100 is constituted of a variable light attenuator 11, a light branching part 13, a light receiving part 16 and a control circuit 19 controlling the variable light attenuator 11 so that an photoelectric current signal 17 from the light receiving part is stabilized to a prescribed value. The control circuit 19 is constituted of a current/voltage convertor 20, a reference voltage generating circuit 22, an error signal detector 24, a reference voltage generating circuit 25, a differential amplifier 28 and driving circuits 31a, 31b outputting driving the signals 32a, 32b of the variable light attenuator 11. The variable light attenuator 11 is constituted of a one input two output light branching circuit 2 using a polymer as an optical waveguide medium and heating means 5a, 5b installed in the vicinity of two optical waveguides 4a, 4b on the one input two output light branching circuit 2. The heating means 5a, 5b are driven by the driving signals 32a, 32b.

17. 发明专利

JPH11317706A OPTICAL TRANSMITTER AND MONITORING INFORMATION TRANSMITTING METHOD 失效
公开(公告)号：JPH11317706A
公开(公告)日：1999-11-16
申请号：JP4104399
申请日：1999-02-19
申请人： HITACHI LTD
发明人： TSUSHIMA HIDEAKI , SASAKI SHINYA , NAKANO YUKIO , NAKANO HIROYUKI , TAKEYARI RYOJI , MATSUDA HIRONARI
IPC分类号： H01S3/10 , G08C23/04 , G08C23/06 , G08C25/00 , H01S3/06 , H01S3/067 , H04B3/46 , H04B10/07 , H04B10/077 , H04B10/079 , H04B10/2537 , H04B10/29 , H04B10/294 , H04B10/532 , H04B10/54 , H04B10/548 , H04B10/564 , H04B10/58 , H04B10/08 , H04B10/16 , H04B10/17
摘要： PROBLEM TO BE SOLVED: To transfer optical monitoring information without lowering the optical data output power of an amplifier by allowing an optical multiplexer to wavelength- multiplex an optical data signal amplified by an optical fiber amplifier and an optical monitoring signal so as to send in an optical transmitter and a light repeater. SOLUTION: The optical transmitter multiplexes an optical signal for monitoring input generated by branching a part of outputted light to a data optical signal after being amplified by a dope fiber amplifier and transfers it to the optical repeater. The monitoring device of the optical repeater detects input monitoring optical signal power Pw at the same time of converting an input monitoring optical signal multiplexed by a monitoring optical receiver 6 to an optical signal. The power Pd of a data optical signal obtained by branching a part of the outputted signal by a power splitter 7 is detected by a power monitor 9, and Pw and Pd are made output monitoring electric signals by a controller 10, made output monitoring light signal by a monitoring optical transmitter 11 and multiplexed to a data signal by an optical multiplexer/demultiplexer 5-2 to be outputted. Only a data optical signal is then inputted to an optical fiber amplifier.

18. 发明专利

JPH08274711A OPTICAL TRANSMISSION EQUIPMENT, RECEPTION DEVICE, AND CABLE TELEVISION SYSTEM 失效
公开(公告)号：JPH08274711A
公开(公告)日：1996-10-18
申请号：JP7113595
申请日：1995-03-29
申请人： HITACHI LTD
发明人： TSUSHIMA HIDEAKI , IKUTA AKIRA
IPC分类号： H04N5/40 , H04B10/2507 , H04B10/54 , H04B10/556 , H04N5/00 , H04N5/455 , H04N7/01 , H04N7/16 , H04N7/22 , H04N21/647 , H04B10/00
摘要： PURPOSE: To obtain an optical transmission equipment which can set a difference in light power between an optical transmitter and an optical receiver large and use low-cost optical components by converting an analog modulated signal into a digital modulated signal and optically transmitting it. CONSTITUTION: Analog modulated signals 4-1 to 4-m inputted to the optical transmission equipment are converted by the encoder 6 of an analog modulated signal processor 23 into binary digital signals. Then they are converted by a QAM modulator 7 into digital modulated signals, which are multiplexed by frequency division through a multiplexer 8. Then the optical transmitter 11 converts the signal into a light-intensity modulated signal, which is sent out to an optical fiber 12. This constitution relaxes the demand for a carrier-to-noise ratio and eliminates the need to use optical components with low distortion characteristics, so the difference in light power between the optical transmitter 11 and optical nodes 2(1)-2(p) can be set large. Further, the optical transmission equipment, a reception device, and a CAT system consisting of them in combination can be actualized by using low-cost optical components.

19. 发明专利

JPH06132895A OPTICAL POWER CHANGE COMPENSATING CIRCUIT AND OPTICAL TRANSMITTER 失效
公开(公告)号：JPH06132895A
公开(公告)日：1994-05-13
申请号：JP28136292
申请日：1992-10-20
申请人： HITACHI LTD
发明人： TSUSHIMA HIDEAKI
IPC分类号： H01S3/10 , H01S3/06 , H01S3/067 , H04B10/07 , H04B10/2557 , H04B10/293 , H04B10/564 , H04B10/572 , H04J14/00 , H04J14/02 , H04B10/04
摘要： PURPOSE:To reduce cross phase modulation caused by optical power fluctuation by detecting the optical power change of a main signal, generating a compensating optical signal, synthesizing the signal with the main signal and constantly keeping optical power to be inputted to an optical fiber. CONSTITUTION:Data 1-N lasers for transmission, for which wavelengths are respectively different, and synthesized by a synthesizer after being converted to optical signals. The main signal of a wavelength multiple optical signal provided as the output of the synthesizer is amplified by an optical amplifier, inputted to the branch path of an optical power change compensating circuit 2-1 and branched into two signals. A first branched main signal is inputted to the synthesizer, and a second main signal is inputted to a photodetector. The photodetector outputs a signal in proportion to the optical power, and the signal from the photodetector is subtracted from a reference signal and outputted by a subtracter. A bias signal is added to the signal from the subtracter and outputted to a drive circuit by an adder, the drive circuit drives a laser for compensation with a current proportional to this signal, this signal is amplified by the optical amplifier, and this compensating optical signal and the first main signal are synthesized by the synthesizer and outputted to the optical fiber.

20. 发明专利

JPH04175732A LIGHT IMPLANTATION SYNCHRONOUS DEVICE, LIGHT RECEIVING DEVICE AND OPTICAL COMMUNICATION DEVICE 失效
公开(公告)号：JPH04175732A
公开(公告)日：1992-06-23
申请号：JP30244790
申请日：1990-11-09
申请人： HITACHI LTD , HIROTA OSAMU
发明人： HIROTA OSAMU , SASAKI TAKESHI , YOSHIDA NORIHIRO , YAMAZAKI KOICHI , TSUSHIMA HIDEAKI
IPC分类号： G02F2/00 , H04B10/2507 , H04B10/516 , H04B10/61
摘要： PURPOSE:To sharply improve the reception sensitivity and bit error rate of coherent optical communication by constituting a light receiving device with a light implantation synchronous device and a light homodyne detecting device homodyne-detecting the signal light outputted from the light implantation synchronous device. CONSTITUTION:A light receiving device 13 is constituted with an implantation synchronous laser 8 implanting the signal light and a light homodyne detecting device 3 homodyne-detecting the output light from the implantation synchronous laser 8. A built-in light implantation synchronous device 7 can improve the bit error rate characteristic of the received light, if the intensity and bit rate of the signal light are made the same as those of the conventional coherent optical communication system, the code error rate of the received signal can be reduced. The light receiving device 13 with the signal/noise characteristic much higher than that of the conventional coherent optical communication system can be realized.

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