Patent ID: 7830933

Claim:
An optical transmitter, comprising: a plurality of transmitter units each providing a Peltier device, a laser diode whose temperature is controlled by said Peltier device, and a thermistor to sense said temperature of said laser diode; and a driver to determine a driving current for said Peltier devices based on said temperatures sensed by said thermistors, wherein said Peltier devices each provided in respective transmitter units are connected in series with respect to said driver, wherein at least one of said optical transmitter units provides a bypassing unit connected in parallel to said Peltier device provided in said at least one of said optical transmitter units, said bypassing unit bypasses a portion of said driving current and said bypassing unit includes a switching device and a low-passing filter to eliminate a switching noise of said switching device, and wherein said driver includes a bypass control unit to control said bypassing unit provided in said at least one of said transmitter units.