OPTICAL TRANSMITTER, OPTICAL TRANSMITTER AND RECEIVER, OPTICAL COMMUNICATION SYSTEM, TRANSMISSION WAVE LENGTH CONTROL METHOD AND OPTICAL COMMUNICATION METHOD

摘要

PROBLEM TO BE SOLVED: To control a wave length without requiring the use of a reference wave length and strict stable wave length control and to improve a wave length multiplexing by controlling transmission wave length under the control of light source temp. in a self optical transmitter and executing control so as to permit a wave length interval between the transmission wave length of the self optical transmitter and that of another optical transmitter which is adjacent at one of a long wave length side or a short wave length side to be the prescribed interval. SOLUTION: A control circuit 101 controls the output wave length of a wave length variable light source 103 and the transmissive wave length of a wave length variable band-pass filter 105 in order to avoid a crosstalk with another station. A temp. controller 108 is provided with an input terminal from a temp. sensor, an output terminal to a temp. control element and the input terminal for setting control temp. from an external part. The temp. of the wave length variable light source 103 is controlled based on a signal from the control circuit 101. The wave length variable light source 103 outputs light to an optical modulator 109. An external modulator 109 modulates the strength of light which is made incident from the wave length variable light source 103 based on a transmitting signal and the modulated light is outputted to an optical branching/joining element 104.