Measurement of intermodulation distortion in high-linearity photodiodes

Abstract

Accurately characterizing third order intermodulation distortion (IMD3) in high-linearity photodiodes is challenging. Two measurement techniques are evaluated-a standard two-tone measurement and a more complicated three-tone measurement technique to measure IMD3. A model of the measurement system is developed and used to analyze the limitations of the two techniques in determining the distortion of highly linear photodiodes. Experimental validation is provided by comparing the simulation trends with IMD3 results measured on two types of waveguide photodiodes: 1) an InP based uni-traveling-carrier (UTC) photodiode and 2) a Ge n-i-p waveguide photodetector on Silicon-on-Insulator (SOI) substrate.

Quantifying current-dependant quantum efficiency photodiode nonlinearities

“…While work to determine the source of photodiode nonlinearities has begun [1][2][3][4][5], accurate mathematical models of p-i-n photodiode nonlinearities have yet to be developed. In addition, several different measurement systems are being used to measure nonlinearities, and only recently has progress has been made in reconciling these systems [6,7] to insure that accurate distortion data is being taken. This paper presents a mathematical model to calculate photodiode nonlinearity produced by current-dependent quantum efficiency effects, and compares the model to measured nonlinearity data.…”

Experimental and Simulation Analysis of Two-Tone and Three-Tone Photodetector Linearity Characterizing Systems

“…Previous works have demonstrated the study of the influence caused by the nonlinearity of the optical source. [6] In this work, a simulation model is developed to systematically investigate the influence of the bias shift from the quadrature point of the modulator in the two-tone setup. Additionally, we analyze the two-tone and three-tone measurements through mathematical calculations and experiments.…”

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

“…A schematic diagram of the setup is shown in Figure 2.5 [61]. The three-tone method is free of the interference from second harmonics produced by the modulators [78]…”