Voltage-dependent nonlinearities in uni-traveling carrier directional coupled photodiodes

Abstract

Voltage-dependent responsivity nonlinearities are characterized experimentally and analytically for unitraveling carrier directional coupled photodiodes (DCPD) with two types of design variations. OIP3 data follows the voltage-dependent responsivity predictions for both MMI width and PD width variations of the baseline DCPD. A maximum OIP3 of 39dBm was achieved for a device with a 3µm wide PD at 20mA and 4V.

Development of an Optically Modulated Scatterer Probe for a Near-Field Measurement System

“…These devices are less suited for use at frequencies in the millimeter-wave region compared to a uni-traveling carrier (UTC) waveguide structure [19]. In future work we will investigate waveguide photodiodes because they are prime candidates for higher frequency applications due to the decoupling of the transit time (namely the intrinsic region thickness) and device capacitance where the bandwidth is limited by capacitance rather than transmit time [20,21]. This waveguide style also offers the advantage of integrating the optical coupling into the probe via a photonic integrated circuit [22].…”

Small-Signal Analysis of the Voltage-Dependent Nonlinearity in High-Power Uni-Traveling-Carrier Photodiodes

“…The structures studied actively lately to handle the high optical power include uni-travelling-carrier (UTC) and modified uni-travelling-carrier (MUTC) PDs. [1][2][3][4][5][6] In UTC or MUTC PD structures, the absorption occurs in or near the ptype absorber, thereby removing or minimizing the slow hole transport. Only the high-mobility electrons need to cross the depletion region, enabling faster carrier sweepout and higher optical-power handling.…”

“…In UTC and MUTC PDs, the dominant nonlinearity mechanism is known to be the voltagedependent responsivity, which is caused by the interplay of the Auger recombination in the p-absorber and the impact ionization in the high-electric-field depletion region. 5) Recently, an OIP3 value as high as $50 dBm has been demonstrated with an MUTC PD at high photocurrent. 6) In this paper, a small-signal analysis is applied to analyze the nonlinearity caused by the voltage-dependent responsivity in the PD.…”

RF Characterization and Modeling of High-Power InGaAs/InP Photodiodes for Analog Optic Links

“…I expanded the study to include 4×1 Wilkinson combiners and HD-MUTC photodiode arrays in order to achieve higher output power and improved linearity. A 6 dB OIP3 improvement has been shown with the 4×1 combiner circuit and the 2×1 combiner circuit reaches over 50 dBm OIP3 at 20 GHz.Various measurement-based models have been developed to explain photodiode nonlinearities[71,102,103], mostly in terms of voltage-dependent responsivity. However, there are few studies on the physical effects that cause nonlinear phenomena in the PDs that employ the UTC concept.…”