Design and optimization of the photodetector structures with planar mirror optical microcavity

Summary form only given. The expression of the quantum efficiency (η) was derived for two type of photodetector-microcavity combination: one with photodiode active regions placed inside two-end mirrors of an optical microcavity, and another with the optical microcavity with airgap placed on the top of the microcavity. The two-end planar mirrors serve to "trap" the optical beam by repeated reflection and to allow the optical signal to have more than one absorbing path inside the active region of the photodiode. The dependency of the photoresponse on various design parameters is investigated for a resonant cavity pin photodiode on InP/InGaAs/InP and for a silicon photodiode with airgap optical microcavity. Also included are the experimental results regarding the enhancement of silicon photodiode sensitivity at 1060 nm using optical microcavity out of resonant conditions. The fabricated photodiode achieved a quantum efficiency of ∼30% due to low reflectivity of the top mirror.