A method of manufacturing an optical transmitter includes assembling a laser device on a module including a temperature sensor and a temperature controller. An optimum operating temperature of the laser to minimize optical distortion is determined at a temperature within a range between which distortions were determined at multiple temperatures. The temperature controller is selectively adjusted so as to operate the laser at the optimum temperature. The distortion may also be monitored during active laser operation. The temperature controller may be selectively adjusted, based on the monitoring of the distortion, so as to operate the laser at a new controlled temperature nearer that which produces the temperature-dependent distortion minimum.