Patent ID: 7839907
Filing Date: 2010-11-23
Classification: G02F,H01S

Abstract:
1. A laser driving apparatus comprising: a laser device that includes an excitation laser unit that emits excited laser light and an optical wavelength conversion element that converts the excited laser light, as a fundamental wave, to laser light having a predetermined wavelength, and that emits the laser light, as an optical output, whose wavelength is converted by the optical wavelength conversion element; a driving section that drives the excitation laser unit of the laser device by a pulse current; an optical detecting section that detects an average value of the optical output in a pulse form emitted from the laser device and outputs the average value as an optical detection value; a current detecting section that detects a value corresponding to an average value of the pulse current and outputs the value as a current detection value; an efficiency detecting section that outputs, as an efficiency value, a value obtained by dividing the optical detection value by the current detection value; a maximization control section that receives as input the efficiency value and derives a temperature setting value such that the efficiency value is maximum; a temperature control section that controls a temperature of the optical wavelength conversion element to reach the temperature setting value; wherein the maximization control section holds in advance a characteristic of the efficiency value for the temperature setting value and sets, as Tm, the temperature setting value at which the efficiency value in the characteristic is maximum, then the maximization control section first outputs a temperature setting value T