High bandwidth, high responsivity waveguide-coupled germanium p-i-n photodiode

Abstract

A novel waveguide-coupled germanium p-i-n photodiode is demonstrated which combines high responsivity with very high -3 dB bandwidth at a medium dark current. Bandwidth values are 40 GHz at zero bias and more than 70 GHz at -1 V. Responsivity at 1.55 µm wavelength ranges from 0.84 A/W at zero bias to 1 A/W at -1 V. Room temperature dark current density at -1 V is about 1 A/cm2. The high responsivity mainly results from the use of a new, low-loss contact scheme, which moreover also reduces the negative effect of photo carrier diffusion on bandwidth.

−1 V bias 67 GHz bandwidth Si-contacted germanium waveguide p-i-n photodetector for optical links at 56 Gbps and beyond

“…A germanium waveguide p-i-n photodetector (WPD) is a critical building block in silicon photonics optical interconnects and has been studied extensively [1][2][3][4][5][6][7][8][9][10][11][12][13]. Optical receivers based on high opto-electrical bandwidth, high responsivity and low dark current germanium photodetectors substantially enhance the performance of Si-based optical interconnects.…”

100-Gbps RZ Data Reception in 67-GHz Si-Contacted Germanium Waveguide p-i-n Photodetectors

“…Germanium waveguide p-i-n photodetectors have been studied extensively for this purpose as they can be realized on silicon photonic integrated circuits [1]- [13]. Conventional Ge p-i-n photodetectors require a metal contact on Ge to form the p-i-n junction.…”

67 GHz uni-traveling carrier photodetector on an InP-membrane-on-silicon platform

“…Recently, InP-based modified UTC-PDs on Si showed good DC characteristics and excellent power handling capabilities [3]. Its 3 dB bandwidth, however, is lower than that reported for Ge-based p-i-n PDs [4], primarily due to a relatively large device area and the associated large capacitance.…”