DRIVING METHOD FOR SEMICONDUCTOR LASER

摘要

PURPOSE:To suppress the modal noises of a transmission system using a multimode optical fiber by superposing high-frequency currents through a method in which the waveform of driving currents is brought to a waveform where the waveform of driving currents returns to a predetermined DC bias value at every period of the high-frequency currents. CONSTITUTION:Driving currents have a waveform returning to DC bias currents set at a value slightly lower than the oscillation threshold of a semiconductor laser 2 at every period of high-frequency currents to the DC bias currents. The semiconductor laser 2 is driven by such a waveform, thus reducing the coherent properties of output beams without being affected even by the variation of the parameter of the semiconductor laser 2 or the amplitude of signal currents.