ABSTRACT
Distributed InGaAs metal-semiconductor-metal photodetectors are presented which possess the potential to overcome the bandwidth limitations arising from the RC time constant and high optical power levels in lumped-element detectors. The devices consist of vertically-coupled waveguide-integrated MSM detectors in conjunction with a coplanar waveguide transmission line. The slow-wave character of this structure allows for velocity-matching between the optical and electrical waveguide. Based on simulation calculations of representative device structures and operating conditions, design rules for wideband operation ≥ 200 GHz are given. The results indicate that the absorption volume of velocity-matched distributed MSM detectors can exceed that of lumped-element devices by more than an order of magnitude without impairing the bandwidth which results in a correspondingly larger optical saturation power. Essential device parameters used in device modeling are obtained from measurements of fabricated test structures.
