Ridge laser with spot-size converter in a single epitaxial step for high coupling efficiency to single-mode fibers

We report on a 1.55-μm InGaAsP MQW laser diode with an integrated spot-size converter fabricated in a single epitaxial step using conventional photolithography. The laser structure uses a conventional ridge guide for the active layers and a second larger ridge for the passive waveguide. Low-beam divergence of typically 9/spl deg/×9/spl deg/ results in about 3-dB coupling losses, with a cleaved optical fiber.