| 摘要 |
A semiconductor photodetector is disclosed which can have a high responsivity, high saturation power, and high bandwidth. The photodetector comprises a waveguide structure comprising: an active waveguide comprising an absorber for converting photons conveying an optical signal into charge carriers conveying a corresponding electrical signal; a carrier collection layer for transporting the charge carriers conveying the electrical signal; and a secondary waveguide immediately adjacent to the carrier collection layer, for receiving the photons to be detected, and which is evanescently coupled to the active waveguide. The secondary passive waveguide layer in the photodetector epitaxial structure enables the use of fast carrier transport material to generate high intrinsic bandwidth and travelling wave techniques associated with a scheme of evanescent coupling to increase the responsivity, saturated output power and bandwidth. This enables a detector with an ultra-thin absorption layer implying a high intrinsic bandwidth for the device. This can be combined with a travelling wave technique to overcome the limitation on the bandwidth due to the depletion capacitance, resulting in a high bandwidth, high responsivity, high power photodetector.
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