公开(公告)号：GB2299474A

公开(公告)日：1996-10-02

申请号：GB9606886

申请日：1996-04-01

Applicant: NEC CORP

Inventor： MICHISHITA YUKIO

IPC: G02F1/35 ,  G02F2/00 ,  H04B10/2563 ,  H04B10/29 ,  H04B10/299 ,  H04L7/00 ,  H04B10/17

Abstract: The optical regenerator receives an input signal 11 which is divided by beam splitter 12. One divided signal 14 is passed via optical directional splitter 16 (or circulator 31, fig 3) to act as an input to an optical clock generator 21. The output of clock generator 21 is returned to the same port 18 of the directional splitter 16 as that from which it emerged and thence to an optical regenerator device 15 which also receives a signal directly from the beam splitter 12.

公开(公告)号：GB2299474B

公开(公告)日：1999-04-07

申请号：GB9606886

申请日：1996-04-01

Applicant: NEC CORP

Inventor： MICHISHITA YUKIO

IPC: G02F1/35 ,  G02F2/00 ,  H04B10/2563 ,  H04B10/29 ,  H04B10/299 ,  H04L7/00 ,  H04B10/17

Abstract: In a data communication system, a circuit for regenerating an optical signal that is deteriorated during the course of transmission has an optical clock generator for generating an optical clock signal whose frequency is equal to the bit rate of an optical signal input to a preselected port thereof. The clock generator outputs the clock signal via the same port as the optical signal is input. The circuit is capable of regenerating the optical signal while efficiently separating the optical signal and clock signal respectively input to and output from the clock generator.

公开(公告)号：FR2762170A1

公开(公告)日：1998-10-16

申请号：FR9804380

申请日：1998-04-08

Applicant: NEC CORP

Inventor： MICHISHITA YUKIO

IPC: H04J14/00 ,  H01S3/13 ,  H04B10/07 ,  H04B10/296 ,  H04J14/02 ,  H04B10/16

Abstract: The device comprises an optical amplifier (110) which receives optical multiplexed signals at an input (180) and feeds them to an output (190). An optical detection circuit (221) is provided and includes a partial optical bypass arrangement (120a) extracting some of the amplified optical output. This is fed to an optical demultiplexer (221d) which separates out an individual component (e.g. lambda 3) from the group of optical signals. An optical/electrical converter (221b) converts the component optical signal which has been demultiplexed into a component electrical signal. This electrical signal then passes to a level detecting circuit (221c) which provides an input to a gain control stage (230). The latter controls the gain of the optical amplifier in response to the detected level of the particular wavelength component selected. In an alternative arrangement, several light wavelength components may be isolated and used to provide a gain control signal.

公开(公告)号：DE69627959T2

公开(公告)日：2003-11-27

申请号：DE69627959

申请日：1996-10-29

Applicant: NEC CORP

Inventor： AOKI YASUHIRO ,  OGATA TAKAAKI ,  YONEYAMA KENICHI ,  MICHISHITA YUKIO ,  SATO YOSHIRO

IPC: H01S3/10 ,  H01S3/13 ,  H01S3/06 ,  H04B10/17

Abstract: Optical surge preventing systems and methods for rare earth-doped optical fiber amplifiers are disclosed. The systems are so arranged as to cause any signal exist in a doped fiber section so as not to excite too much the rare earth elements in the doped fiber section. In one embodiment, a background signal light with such a wavelength as to cause induced emission in the doped fiber section is always coupled into the doped fiber section regardless of whether a message signal light exists or not. The background signal light may be generated by any suitable light source or a light spontaneously emitted from either end of the doped fiber section. In another embodiment, a dummy signal light is coupled into the doped fiber section if the level of the message signal light becomes less than a predetermined value. Coupling of the background signal light or the dummy signal light into the doped fiber section may be done from either of the message signal input and output sides.

公开(公告)号：DE69627959D1

公开(公告)日：2003-06-12

申请号：DE69627959

申请日：1996-10-29

Applicant: NEC CORP

Inventor： AOKI YASUHIRO ,  OGATA TAKAAKI ,  YONEYAMA KENICHI ,  MICHISHITA YUKIO ,  SATO YOSHIRO

IPC: H01S3/10 ,  H01S3/13 ,  H01S3/06 ,  H04B10/17

Abstract: Optical surge preventing systems and methods for rare earth-doped optical fiber amplifiers are disclosed. The systems are so arranged as to cause any signal exist in a doped fiber section so as not to excite too much the rare earth elements in the doped fiber section. In one embodiment, a background signal light with such a wavelength as to cause induced emission in the doped fiber section is always coupled into the doped fiber section regardless of whether a message signal light exists or not. The background signal light may be generated by any suitable light source or a light spontaneously emitted from either end of the doped fiber section. In another embodiment, a dummy signal light is coupled into the doped fiber section if the level of the message signal light becomes less than a predetermined value. Coupling of the background signal light or the dummy signal light into the doped fiber section may be done from either of the message signal input and output sides.

公开(公告)号：FR2767423A1

公开(公告)日：1999-02-19

申请号：FR9810514

申请日：1998-08-18

Applicant: NEC CORP

Inventor： MICHISHITA YUKIO

IPC: H01S3/10 ,  H01S3/06 ,  H01S3/067 ,  H01S3/13 ,  H01S3/131 ,  H04B10/07 ,  H04B10/29 ,  H04B10/294 ,  H04J14/00 ,  H04J14/02 ,  H01S3/09

Abstract: The output from the optical amplifier (1) passes to a coupler (2) and wavelength separator (12) where the level of amplified spontaneous emission level for each wavelength is measured by a detector (13) and the output values used to control (10) the light pump (4).