Efficient coupling in integrated twin-waveguide lasers using waveguide tapers

We demonstrate a 1.55-μm wavelength, InGaAsP-InP, twin-waveguide (TG) laser integrated with passive ridge waveguides using low-loss taper couplers. The lateral taper on the laser waveguide induces efficient resonant coupling of light between the active and passive layers. The device is fabricated using low-cost conventional photolithography and reactive ion etching of a TG structure grown by gas-source molecular beam epitaxy. This structure is suitable for integrating a variety of photonic devices without requiring epitaxial regrowth.