High power and highly linear monolithically integrated distributed balanced photodetectors

Abstract

Abstract-A distributed balanced photodetector with high saturation photocurrent and excellent linearity has been experimentally demonstrated. The maximum linear direct current (dc) photocurrent of 33 mA per branch is equivalent to 66mA in single-ended photodetectors. A setup for investigating the alternating current (ac) linearity of the receiver is proposed and experimentally demonstrated. The receiver exhibits high ac linearity, even under high power operation. The bandwidth of the receiver remains unchanged when the effective dc photocurrent is varied from 1 mA to 21 mA. The distribution of photocurrents was also measured. Device length for optimum radiofrequency (RF) performance is calculated and implemented in the design. A correlation between the dark current of the photodiodes and their failure mechanism has been established. Analyzing the failure mechanism, junction diodes are found to be more suitable for high power applications.Index Terms-Analog fiber optic links, balanced photodetectors, failure mechanism, high photocurrent, high power photodiodes, metal-semiconductor-metal (MSM), microwave photonics, optical receivers, p-i-n, radiofrequency (RF) photonics.

High-power heterogeneously integrated waveguide-coupled balanced photodiodes on silicon-on-insulator

“…Various approaches including normal-incidence [1,2], waveguide photodiodes [3,4], and velocity-matched distributed configurations [5] have been employed to fabricate high-power monolithic balanced photodiodes. Waveguide photodiodes can achieve high bandwidth-efficiency products and, by their nature, have become key devices in photonic integrated circuits.…”

A Perspective on Nanowire Photodetectors: Current Status, Future Challenges, and Opportunities

“…As a strategy of enhancing photon absorption, the applications of resonant structures in the PD design have been demonstrated [1], [2]. Researchers have also developed waveguide-based detectors to get around the wellknown efficiency-speed tradeoff [3], [4] and traveling-wave waveguide-distributed PDs for high power and large bandwidth [5], [6]. Unfortunately, all these approaches offer limited opportunities for device scaling, while adding layers of complexity to the issue of integration with nanoscale electronic components.…”

High‐Power Distributed Photodetectors for RF Photonic Applications

“…High photocurrent density also causes excessive Joule heating (bias voltage  photocurrent) of the absorption region leading to thermally activated dark current runaway [3], which eventually results in catastrophic photodiode failure. Dark current and the effective barrier height for dark current flow are the fundamental device parameters involved in thermal runaway [4]. Photodetectors with low dark currents and high effective barriers have been found to sustain larger amounts of Joule heating before catastrophic failure.…”

“…Photodetectors with low dark currents and high effective barriers have been found to sustain larger amounts of Joule heating before catastrophic failure. For example, metalsemiconductor-metal (MSM) photodetectors have much lower effective barriers than p-i-n diodes, and consequently, MSMs fail at 700 K [5] whereas p-i-n junctions can withstand temperatures up to 900 K [4]. It should also be mentioned that device fabrication induced damage, such as poor surface passivation and plasma induced damage, can increase the dark current and contribute to premature device failure.…”