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 percent quantum efficiency for lengths at least as short as 114 µm. Frequency response up to 5 GHz shows only a simple parasitic-limited rolloff 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.