Passive active resonant coupler platform with tapered passive waveguide

The authors demonstrate an ultra-compact, low-loss vertical mode transfer between a 1.55 mu m InGaAsP QW active waveguide and a well-confined passive waveguide using a 100 mu m long taper on both the active and passive waveguide. The radiation loss during the transfer was measured to be less than 0.5dB. The device was fabricated using a single epitaxial growth and conventional fabrication schemes. This approach will improve the new platform technology for integrating active and passive photonic devices reported earlier.