Investigation of Free Space Optical Detection Module Operating at the Wavelength Range of 8-12 μm
The paper presents the construction and test results of a long-term radiation detector module for free space optical communication operated at the wavelength range of 8–12 μm. In the module a Polish detector manufactured in the company Vigo System S.A. was applied. High sensitivity of the detection module was achieved through a multi-layered heterostructure HgCdTe with immersion lens, which is optimized for the radiation detection at the wavelength of 10 μm. Detector noises were reduced as a result of detector cooling by means of four-stage thermoelectric cooler. The developed detection module is dedicated to design a next-generation optical data link. The link will be characterized by a greater range in difficult weather conditions in relation to the currently offered links operating at the shorter wavelengths.
The Free-Space Optics System Using QCL: Models and Solutions
Two of the important issues in the free-space optics (FSO) communication systems are the building sway and atmospheric interference. In this paper, the optimization models for these issues are established and solved to obtain the desirable transmitter power, transmitter wavelength, transmitter telescope gain, and receiver telescope gain. The solution feasibility relies on using the quantum cascade laser (OCL) in transmitters. Details of the numerical experiments are also reported.
Effect of antioxidants, on deterioration by partial discharge in LDPE and XLPE [insulation materials]
The effect of antioxidants in low-density polyethylene (LDPE) and cross-linked polyethylene (XLPE) on deterioration by partial discharge (PD) was investigated. Experiments were conducted using LDPE and XLPE samples containing phenolic antioxidants. Samples subjected to the PD were analyzed using atomic force microscopy and Fourier transform infrared analysis (AFM and FTIR). AFM images demonstrated that the magnitude of pits created in the sample containing antioxidants was smaller than that in samples containing no antioxidant. FTIR showed that oxidative degradation occurred on LDPE and XLPE surfaces when they were subjected to PD. These results confirmed that the amount of oxidized substances was smaller in samples containing phenolic antioxidants than in those containing no antioxidant. This report elucidates the mechanism of antioxidant action on deterioration by PD.