Optoelectronic Properties of InGaAs/InGaAsP Multiple-Quantum- Well Waveguide Detectors.

The performance of InGaAs/InGaAsP multiple-quantum-well material as the absorbing medium in waveguide detectors has been studied. We observe no deleterious saturation effects up to absorbed power of ~1 mW, with strong enough absorption for a four-well separate confinement heterostructure to provide >~ 80% quantum efficiency for lengths at least as short as 114microns. Frequency response up to 5 GHz shows only a simple parasitic-limited roll-off which matches the measured impedence. These results provide sound evidence that the carrier trapping problem in this quantum-well material combination is much less serious than that in other material systems. In addition to quantum- well field effect optical devices, this has important consequences for photonic integration, since the same quantum-well layers may simultaneously serve as a gain medium and as a detecting medium.