Uni-traveling-carrier photodetector with high-contrast grating focusing-reflection mirrors

TL;DR

This paper introduces a novel uni-traveling-carrier photodetector with an integrated focusing-reflection mirror using a high-contrast grating, significantly enhancing responsivity without compromising bandwidth.

Contribution

The work presents a new FR-UTC-PD structure with a non-periodic concentric circular high-contrast grating that improves responsivity by 36.5% at 1.55 μm wavelength.

Findings

Responsivity increased by 36.5% with the integrated mirror.

Bandwidth remains at 18 GHz for 40-μm-diameter PDs.

RF output power of -1.77 dBm at 10 GHz.

Abstract

A novel uni-traveling-carrier photodetector (UTC-PD) structure with an integrated focusing-reflection (FR) mirror realized by a non-periodic concentric circular high-contrast grating (NP-CC-HCG), referred to as FR-UTC-PD, is proposed to enhance responsivity in conventional UTC-PDs. The FR-UTC-PD allows improving the responsivity by 36.5% at a 1.55-um wavelength as compared to a UTC-PD without integrated an FR mirror with 84.59% reflectivity. For 40-um-diameter PDs, the obtained 3-dB bandwidths are unaltered with values of 18 GHz at -3.0 V bias voltage. The radio-frequency (RF) output power and photocurrent are -1.77 dBm and 17.56 mA, respectively, at 10 GHz and the -6.0 V bias voltage.