Title:
CONTROLLER FOR LINBO3 MACH-ZEHNDER INTERFERENCE TYPE MODULATOR
Document Type and Number:
Japanese Patent JPH05232412
Kind Code:
A
Abstract:
PURPOSE:To enable the optimum maintenance of the operating point of a Mach- Zehnder interference type modulator by compensating a bias voltage in accordance with the change quantity of a light signal. CONSTITUTION:The data signal inputted to an input terminal 3 is inputted through a driving circuit 4 and a coupling capacitor 5 to the Mach-Zehnder interference type modulator LN-MOD 2. The light waveforms modulated by the LN-MOD 2 is outputted through an optical branching device 7 to a photodiode 9 and is passed through a current-voltage converter 10, by which the average value of light wavelengths is detected. The detected average value of the light waveforms is compared with the reference value obtd. through an operational amplifier 14 in an operational amplifier 11 and an error voltage is generated in the output of the operational amplifier 11. The error voltage is fed back via a filter 13 to a bias supply circuit 6, by which the operating point of the LN-MOD 2 is most adequately controlled.
Inventors:
ASAHI KOJI
Application Number:
JP3671292A
Publication Date:
September 10, 1993
Filing Date:
February 24, 1992
Export Citation:
Assignee:
NEC CORP
International Classes:
G02F1/03; G02F1/01; H01S5/06; H04B10/07; H04B10/516; H04B10/54; H04B10/564; H04B10/61; (IPC1-7): G02F1/03; H01S3/103; H04B10/04; H04B10/06
Attorney, Agent or Firm:
Yosuke Goto (2 outside)