Method of controlling temperature of semiconductor laser, temperature control device of semiconductor laser and non-transitory computer-readable medium

A temperature control device of a semiconductor laser comprising:

• a temperature control element that controls a temperature of the semiconductor laser with use of a temperature changing according to a supply current supplied to the temperature control element;
• a detector that detects a temperature of the temperature control element;
• a control unit that controls the supply current so that the temperature of the temperature control element is changed to a target temperature,
• wherein:
• the control unit has a digital filter that calculates the supply current according to a difference between the target temperature and the temperature detected by the detector;
• and
• the control unit performs a control for maintaining a calculated value calculated by the digital filter at a threshold when it is detected that the calculated value reaches the threshold even when a difference between the target temperature and the temperature detected by the detector is changed, the threshold being equal to or less than an output limit of the digital filter.

A non-transitory computer-readable medium storing a program that causes a computer to execute a process controlling a temperature of a semiconductor laser, the process comprising:

• detecting a temperature of a temperature control element by a sensor;
• controlling a supply current so that the temperature of the temperature control element is changed to a target temperature, the temperature control element controlling a temperature of the semiconductor laser by a temperature changing according to the supply current supplied to the temperature control element;
• and
• performing a control for maintaining a calculated value calculated by a digital filter at a threshold when it is detected that the calculated value reaches the threshold even when a difference between the target temperature and the temperature detected by the detecting is changed, the calculated value being the supply current according to a difference between the target temperature and the temperature detected by the detecting, the threshold being equal to or less than an output limit of the digital filter.