Vector design of phase-only diffractive WDM element

摘要

The design of a phase-only diffractive WDM element, based on vector theory, is demonstrated. The adopted method of this design is a rigorous method based on the rigorous electromagnetic computation models the Beam propagation method (BPM)., Rayleigth-Sommerfield diffraction theory, and iterative optimization method. This phase-only diffractive optical WDM element (PDOE-WDM) is motivated by the intersatellite optical communication (IOC). And the motivation also raises the demands of large numerical aperture, polarization insensitivity and high diffraction efficiency. In order to predict the phase filter of DOE and the large angle diffraction precisely, a vigorous vector method has been adopted. The complex optical field right behind the BOE is computed by the Beam propagation method (BPM). And the diffraction between the back side of DOE and focusing plane is computed by the means of Rayleigth-Sommerfield (RS) diffraction theory, a more rigorous diffraction theory than Fresnel diffraction theory. The vector BPM method and the RS diffraction theory combined with FFT technology come along with the improvement of PDOE-WDM performances. And the high performance PDOE-WDM will play an important rule in IOC to increase communication rate as well as decrease volume and weight.