Vertically integrated electro-absorption modulated lasers and methods of fabrication

Abstract

Electro-absorption modulators (EAM) and monolithically integrated electro-absorption modulated lasers (EML) and methods of fabrication are disclosed. Vertically stacked waveguides for a distributed feedback (DFB) laser, an electro-absorption modulator (EAM) and a passive output waveguide are vertically integrated, and the DFB laser, EAM and output waveguide are optically coupled using laterally tapered vertical optical couplers. Laterally tapered vertical optical couplers provides an alternative to conventional butt-coupling of a laser and EAM, offering improved reliability for high power operation over extended lifetimes. Optionally, the EML comprises monolithically integrated electronic circuitry, e.g., driver and control electronics for the DFB laser and EAM. Beneficially, integrated EAM driver and control circuitry comprises a high-speed electro-optical control loop for very high-speed linearization and temperature compensation, e.g. to enable advanced modulation schemes, such as PAM-4 and DP-QPSK, for analog optical data center interconnect applications. Some embodiments are compatible with fabrication using a single epitaxial growth.