Design Research And Fabrication Of Polarizing Film

In recent years, thin-film polarizers are widely used in modern microelectronics and optoelectronics industries. The design of polarizing film focuses on broadband, large acceptance angle for LCD projectors and broadband, high damage threshold for laser. To meet the optical requirements in modern optical deverices, we mainly designed flat-type polarizers which have simple structure and high extinction ratio for applications in optical fiber communication. In this thesis, the transfer matrix method in multilayers is used to obtain the working wavelength, combined with the transmission and the reflection properties in three classic multilayer films. Several polarizing films designed for single-band and double-bands are described, and one for C band is fabricated. The research contents in detail are as follows.(1) The properties of characteristic matrix, the transmission and the reflection of three multilayer films,(H/2L H/2)S,(HL)s and (HL)SH, have been studied. Several single-band thin-film polarizers’ designed based on the quarter wavelength are described. By analyzing the impact of structural parameters, such as the number of periods and materials of multilayers, several single-band polarizing films are designed for1550nm with high extinction ratios with less layers. Considering the practical problems of film thickness monitering, we designed single-band polarizing films with a single monitering wavelength.(2) Base on the principles of single-band polarizing films, double-band ones are designed. In classic multilayer film (H/2L H/2)s,(HL)S and (HL)SH, there may be several working wavelengths, but the structural parameters are restricted by working wavelengths. Several double-band polarizing films are designed for1310and1550nm, by combining two single-band ones in different center wavelengths to achieve high transmission for P light in working wavelengths.(3) A C band polarizing film, A|(HL)’H|D, is fabricated using vacuum coating machine and its property is measured in a test optical path. The test results show that the insertion loss is less than2dB and the extinction ratio is greater than28.5dB in wavelength range of1530-1562nm with an incident angle around65±5°.