Circuit for stabilizing oscillating wavelength of laser diode

Abstract

Abstract PURPOSE:To stabilize an oscillating wavelength with respect to the temperature change in laser diode by performing suitable function conversion for the electric output of a temperature sensor with a converter circuit wherein an A/D converter, a ROM and a D/A converter are combined, controlling a variable wavelength laser diode with a control voltage obtained by said function conversion, and offsetting the change in oscillating wavelength due to the temperature change. CONSTITUTION:The electric output of a temperature sensor 1 which detects the operating temperature of a variable wavelength laser diode is digitalized in an A/D converter 2. The result undergoes suitable conversion in a ROM 3. The digital output of the ROM 3 is converted into the analog value in a D/A converter 4. Thereafter, the signal is applied to the oscillating wavelength controlling electrode of the variable wavelength laser diode 5. Thus, the wavelength change due to the temperature change in said variable wavelength laser diode 5 is offset. When the characteristic of sensor output vs. temperature of the temperature sensor 1 is as shown in Figure (c), the parameter temperature T is offset in Figures (b) and (c). A control voltage Vc is generated with respect to the sensor output Vs as shown in Figure (d). Thus the fluctuation in oscillating wavelength caused by the temperature fluctuation is offset.

Inventors

• 👤 Mikio Yamashita
• 👤 幹夫 山下

Bibliographic Details