Semiconductor laser device and drive control method for a semiconductor laser device

1. Field of the Invention A semiconductor laser device including a semiconductor laser element, a temperature measuring element to measure a temperature, and a temperature regulating unit having the laser element and the temperature measuring element thermally connected thereto. The laser device includes a current detecting unit to detect a driving current applied to the laser element, and a control unit to control the temperature regulating unit using a control function to achieve a substantially constant wavelength output from the laser element. The control function defines a relationship between a predetermined driving current and a predetermined temperature. The control unit is configured to control the temperature regulating unit such that the detected temperature substantially equals the predetermined temperature corresponding to the detected driving current as defined by the control function.