Fabrication And Test Of Sub-micron Grating Based On Lloyd Mirror Interference System

Optical waveguides play an important role in communications, military, electricity, astronomy and so on .The realization of these functions and sensing applications rely on a number of excellent properties of the materials used in waveguide. The fine grating which has periodic structure in the internal waveguide has a light side waveguide switching, wavelength dispersion adjustment and other functions. But unfortunately, the production of small size grating, especially sub-micron gratings, is so difficult because high precision technology. In this paper, a new method that fabrication and testing of sub-micron grating based on Lloyd mirror interference system is proposed. The precision of groove density adjustment by this interference system is very high, and the structure of the new device is more simple, more convenient and more stable than the other device.Based on theoretic analysis and the corresponding experiment research, r the feasibility of the method is discussed in the paper. The main work is as the followings:1)The paper give a theoretical analysis of the light reflection problem on dielectric interface and metal surface .At last, the Al film reflector SIGMA-TFAN-5060R10-1 is elected in the interference system which solves the problem of the limitation of grating period because of the incidence angle in the Lloyd mirror interferometer.2)Specific Lloyd mirror holographic interferometer is built with He-Ne laser and semiconductor green laser respectively and .A lot of work is done to get the high quality and clear stripes the practical problems of spot quality, collimation and beam expander are solved.The CCD acquisition system is set to get interference fringes of wavelength of 632.8nm and 532nm and angles from to 5°to 25°. And the minimum period of the fringes is 630nm.Measure the stripes collected in the experiment through the use of area measurement method.3) The error of optical path can be controlled at 4‰which meet the production requrement. And the error of measurement system designed in the paper is less than 3.4% to meet the basic stripe monitoring requrements.