Fujitsu Corporation

Masaru Onishi

Kazuhiro Suzuki

Yoshinori Ohkuma

Yoko Tahara

Toshiyuki Masuko

An optical wavelength stabilizing system including a laser diode for emitting signal light, a Peltier element for controlling a temperature of the laser diode, and a drive circuit for driving the Peltier element. The signal light is branched into two components by an optical coupler. In an optical path of one of the two components obtained by the optical coupler, there is inserted an optical filter having a portion whose transmittance continuously changes according to wavelength. The signal light component passed through the portion of the optical filter is detected by a photodetector. An output current from the photodetector is converted into a voltage, which is then input into a comparator. The comparator compares the voltage output from the photodetector and a reference voltage to input a voltage difference therebetween into the drive circuit.

Optical wavelength stabilizing system

An electric field absorption light modulation unit includes a light emission device for emitting light and a modulation device for varying a light transmittance thereof of light applied by the light emission device so as to provide the light as a result of modifying thereof. A driving signal generating unit coupled with the electric field absorption light modulation unit generates a driving signal to be applied to the modulation device from an input information signal by making the modulation device vary the light transmittance thereof, and the driving signal generating unit provides the driving signal so that the driving signal in a fluctuation range in which an undesirable level fluctuation may be present, corresponds to a constant working range of the modulation device, the light transmittance thereof staying at a constant value in the constant working range.

Growing community of inventors

Kawasaki, Japan

Masaru Onishi