Monolithic integration of a DFB laser and an MQW optical modulator in the 1.5 µm wavelength range

A monolithically integrated device with an improved structure consisting of an InGaAsP/InP DFB laser and an In-GaAs/InAlAs MQW optical modulator was fabricated by the LPE (liquid phase epitaxy)/MBE (molecular beam epitaxy) hybrid growth technique. The DFB laser in this device was operated at 1.556 μm under CW condition at room temperature. A narrow coupling region between laser and modulator results in a depth of modulation as high as 55 percent at a modulator reverse bias voltage of -5 V. High-speed modulation with a response time of 300 ps was also achieved in this monolithic device.