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Note: Measuring grating periods by diffraction method with a fore-end light path comprising fused fiber couplers and
Bin Sheng1, Guohua Chen1, Yuanshen Huang1
1Engineering Research Center of Optical Instruments and Systems, Ministry of Education and Shanghai Key Laboratory of Modern Optical Systems, University of Shanghai for Science and Technology, Shanghai 200093, China.
Abstract:
Based on the Littrow and Littman configurations for autocollimation, two methods are proposed herein with a fore-end light path comprising fused fiber couplers and fiber port collimators to measure the diffraction grating period. The experimental data from a uniform-line-spacing grating with a nominal value of 1200 lines/mm agreed well with theoretical values and with measurement errors of the Littrow and the Littman configurations of 1.05 × 10-4 and 4.99 × 10-5, respectively. Both methods were demonstrated to reduce the diameter of the laser spot and improve the alignment precision of the measurement system.
