Mode-Locked Laser Diode Laser With Integrated External Cavity
Original Publication Date: 1989-May-01
Included in the Prior Art Database: 2005-Jan-27
Semiconductor mode-locked lasers are of interest as sources of picosecond optical pulses. Gain and absorption sections inside the laser must be modulated at a rate corresponding to the time it takes for a pulse to make a round trip inside the entire laser cavity. The modulation rate can be reduced by increasing the actual length of the laser cavity but this leads to high laser threshold currents. Described herein is a low threshold current mode-locked semiconductor laser having a separate gain section (GS) and an absorption section (AS), these being connected by long low-loss waveguide sections (LLWSs). The ordinarily very large absorption in the unpumped laser regions at the lasing wavelength is reduced by using channeled substrate effects.