Constant Temperature Control Of The Semiconductor Laser Diode Underlying An Adjustable Driving Current

Semiconductor laser diode is a most popular light source that has been widely used in the optical communication and optical fiber sensor, etc. The stability of the laser is largely limited by the system performance. Thus, how to operate the laser in a high efficiency, stability, and safety at an affordable price is a most common problem in some labs and practical applications. This paper is aiming to design and carried out a compact system to drive the laser at a constant temperature underlying an adjustable constant driving current.The controller of semiconductor laser diode includes tow parts: the driving part and the constant temperature control part. In this paper, a variable constant-current driver is proposed for the laser with a well controlled constant operation temperature. This method is carried out by a micro-computer, MSP430, combining with PID algorithm and semiconductor cooler. The experimental results show that a stable output power and central wavelength of the light source is achieved at the temperature accuracy of±0.1℃, according to the environmental temperature changing from 10℃to 40℃. The constant-driving current could be stabilized at±0.1mA in the range of 0 to 200mA.