Fujitsu Corporation

Yoshitaka Shimura

Motoyoshi Sekiya

Tetsuya Kiyonaga

Keisuke Imai

The present invention relates to an optical sender applicable to WDM (wavelength division multiplexing), and a primary object of the present invention is to prevent interchannel crosstalk in WDM. The optical sender includes a light source for outputting a light beam, an optical modulator for modulating the light beam in accordance with a main signal to output an optical signal, and a unit for shutting down the optical signal when receiving at least one of a power alarm relating to on/off of power supply and a wavelength alarm relating to the wavelength of the light beam.

Optical sender, terminal device, and optical communication system each having the optical sender

Disclosed herein is an optical transmitter suitable for stabilization of the output power and wavelength of an optical signal. The optical transmitter includes a light source for outputting a light beam, an external modulator for modulating the light beam according to a main signal to thereby output an optical signal, a power monitor for detecting the power of the optical signal output from the external modulator, and a control unit for controlling the light source so that the power detected by the power monitor becomes stable. The light source is controlled according to the power detected on the downstream side of the external modulator, so that the output power of the optical signal to be obtained can be maintained constant with high accuracy irrespective of variations in loss by the external modulator.

Optical transmitter

A WDM optical transmission apparatus of the present invention comprises: a light source ( ) for generating light whose wavelength is changed according to the temperature and a drive current; a temperature control section ( ) for controlling the temperature of the light source so that a wavelength at the starting of emission of the light source is stabilized in an allowable range of optical output wavelength set in advance; a drive current control section ( ) for controlling the drive current applied to the light source according to the allowable range of the optical output wavelength; a wavelength control section ( ) for detecting a wavelength of light output from the light source and controlling the temperature of the light source based on the detection result, to lead the optical output wavelength into the vicinity of a predetermined target wavelength; and an operation control section ( ) for controlling the start and stop of the control operation of each section at predetermined timing respectively corresponding to the time of optical output generation and the time of optical output stop.

Growing community of inventors

Kawasaki, Japan

Yoshitaka Shimura