Inert gas packaging of InGaAs detector with multistage thermoelectric cooler

Abstract

Inert gas packaging and vacuum packaging are the main packaging method of photodetectors. A multi-stage thermoelectric cooler (TEC) is used to provide low temperature environment for extended wavelength InGaAs focal plane. A gas charging device is established to study nitrogen and krypton gas packaging. The performance of multi-stage TEC under different packaging atmospheres is tested, and the temperature field distribution is simulated by finite element analysis using FLoEFD software. The results show that in inflatable environment the cold side of TEC can achieve low temperature below 220K for the extended wavelength InGaAs detector. Gas conduction heat loss and gas convection heat loss are introduced into the inflatable packaging compared with vacuum packaging, and the relationship between temperature difference and input current under different packaging atmosphere is obtained. The cooling effect of TEC in krypton gas packaging is superior to that in nitrogen packaging, and the temperature of the cold platform can reach 211K and 215K respectively under the same input current of 4.5A. The results of FLOEFD finite element analysis are basically in agreement with the measured results, and the temperature uniformity of the focal plane is good. Because of without using the getter, Inert gas packaging is an economical packaging method for infrared detector.