| 摘要 |
PURPOSE:To prevent the fluctuation of a light beam caused by temperature and humidity with a simple constitution by providing an optical element which consists of an optical glass that surface-reflects a portion of the light beam emitted from a semiconductor laser and an optical detection means which detects the reflected light beam. CONSTITUTION:A light beam L emitted from a light conductor laser 1 is first divided into a light beam L1 which is directed to an optical device main body and a light beam L2 which is directed to a light receiving element 4 by an optical element 5. Since the element 5 is made of optical glasses, the beams L1 and L2 from the element 4 do not vary by temperature and humidity. The light beam is detected by the element 4 and is converted into electrical signals (detection signals) Si which have a current (voltage) in accordance with the light quantity. A controlling circuit 6 controls a bias voltage applied to a driving circuit 2, for example, based on the signals Si so as to feedback-control a driving current i supplied to the laser 1. |
