Integrated directional couplers with photodetectors by hydridevapour phase epitaxy

The hydride vapour-phase-epitaxial crystal growth technique has been used to realise integrated waveguide-photodetectors and, for the first time, integrated directional coupler-photodetectors for detection in the 1.3 μm to 1.55 μm wavelength range. The GaInAsP waveguides which formed the directional couplers had propagation losses of 2±0.5 dB/cm and more than 90% of the guided light was coupled into the photodetectors. The directional couplers were symmetric with respect to the launch port and had 3 dB coupling lengths of about 1.45 mm