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

Abstract

It is demonstrated with small-signal analysis how the voltage-dependent responsivity in the uni-travelling-carrier photodiode (UTC PD) can lead to the intermodulation distortion. A simple expression for the third-order output intercept point (OIP3) is derived and compared with experiments. Reasonable agreements between the theoretical and experimental OIP3 values are observed.

Enhancement in third‐order output intercept point of high‐power photodiodes by nonlinear voltage‐ and current‐dependent responsivities

“…Using the relationship [6], where P fund and P IMD3 are fundamental and IMD3 powers given in W, the OIP3 in W is expressed as Examining the experimental results reported on the MUTC PDs reveals that η V , V and η I , I have different signs. References [1, 2], which report the nonlinear responsivity of surface‐normal HD‐MUTC PDs, show η V , V < 0 and η I , I > 0 due to the interplay of such factors as Auger recombination and impact ionisation in the absorption and depletion layers.…”

“…With the assumption that a nonlinear response of the photodetector is known, it is demonstrated that a mutual cancellation of its bias and current dependence can lead to the enhancement in OIP3. So far, only analyses on the voltage-dependent responsivity have been reported [5,6].…”

“…The first and second terms represent the fundamental signal and the second-order intermodulation distortion (IMD2), respectively, whereas the third term gives the IMD3. Using the relationship OIP3 = P 3/2 fund /P 1/2 IMD3 [6], where P fund and P IMD3 are fundamental and IMD3 powers given in W, the OIP3 in W is expressed as…”