Optimization of the optical scheme of a photodetector module operating in the spectral range of 1.3–1.6 μm

Optical system consisting of single-mode optical fiber and p-i-n photodiode semiconductor chip with InGaAs active layer was investigated. Considered photodetector module has responsivity in 1.3–1.6 μm. The problem of optical power loss due to inaccurate matching between the optical fiber and the active medium of photodiode in photodetector modules is investigated; resolving the power loss problem will lead to an increase in the spectral photosensitivity and external quantum efficiency of the photodetector module. Optimization of optical fiber coupling with semiconductor chip was implemented in Zemax® software with built-in Levenberg–Marquardt algorithm. Also, numerical calculations of the influence of the transverse and longitudinal displacement on optical coupling efficiency in the photodetector module were carried out. The optical system of photodetector module based on standard metal can package was built in Zemax® software. Optimal distances between elements of the photodetector module were calculated, and maximum efficiency of 93.1 % optical coupling between single-mode fiber and photodiode aperture was achieved. The necessary sensitivity of linear micro translators used during the assembly of photodetector modules was determined to ensure the alignment of optical elements with coupling efficiency more than 90 %. The results of this work can be used in the design of photodetector modules. The proposed solutions can be relatively easily modified to create photodetector modules of other spectral ranges.