OPTICAL COMMUNICATION SYSTEM

摘要

PROBLEM TO BE SOLVED: To provide an optical communication system in which a semiconductor laser can be controlled through a simple driving mechanism. SOLUTION: Since variation in the threshold current due to temperature variation is very small in a long wavelength band surface emission semiconductor laser on contrary to a prior art semiconductor laser, variation width of optical output including the temperature variation does not increase when the semiconductor laser is driven with a constant driving current and thereby a constant current supply can be controlled easily using simple circuitry. When upper and lower limits are set in the optical output and the current is controlled to a constant level x within the range of a current (a) determined by the upper limit optical output and an assumed lower limit temperature and a current (b) determined by the lower limit optical output and an assumed upper limit temperature, an output within the optical output range can be obtained.