Abstract: In a VCSEL, vertical cavity surface emitting laser, lateral traveling mode density is reduced by reducing the number of traveling modes available to spontaneous emission of photons in the active cavity region, to suppress spontaneous emission into lateral traveling modes, to increase spontaneous emission into axial normal modes, to lower lasing threshold. The sidewall of the active cavity region is contoured, preferably by a 90.degree. symmetrical V-shaped notch, to internally reflect laterally traveling photons, to suppress lateral traveling modes.

Abstract: A vertical cavity surface emitting laser, VCSEL, and detector combination includes a plurality of VCSEL diodes (14, 16a) monolithically integrated on a substrate (12) A forwardly biased lasing VCSEL diode (14) emits light in a vertical axial direction (26) and in a horizontal lateral direction (44). A laterally adjacent detector VSCEL diode (16a), which is unbiased or is reverse biased, receives the lateral light from the lasing VCSEL diode (14) and generates detector output current, which provides feedback (50) control of the forward biasing circuit (24) for the lasing VCSEL diode (14). The combination also provides an electrical-optical-electrical transducer and isolator.