| The high reflectivity of VCSEL mirrors renders the device very sensitive to small changes in the reflectivity or absorption within the laser cavity. Therefore, the integration of a quantum-well absorber within the VCSEL enables compact, monolithic devices with multiple functions. As a result, the VCSEL exhibits a variety of useful characteristics under different configurations.;In this work, I will discuss the use of a quantum-well absorber within one of the VCSEL mirror stacks. With strategic design and simple biasing circuitry, I have demonstrated experimentally (1) a VCSEL with an integrated quantum-well photodetector, (2) a self-pulsating VCSEL with a controllable quantum-well saturable absorber, (3) a novel technique for VCSEL modulation where the quantum-well absorption is modulated, thereby modulating the laser light output, and (4) an innovative method for optical pickup detection using the bistability in the VCSEL. I will address the theory, design criteria, experimental results, and potential applications for these devices. |
