All-optical interconnection with photorefractive grating array for wavelength divided multiplexing signal

Abstract

We propose an all-optical free-space interconnection with a photorefractive grating array for wavelength division multiplexing (WDM) signal. Input WDM signal propagating on free-space can be branched for each wavelength component and the components are connected to different spatial ports by this interconnection. The wavelength component of WDM signal is diffracted by one index grating, which is induced by two control beams, only when the phase-matching condition is satisfied. The phase-matching condition is determined by incident angles of control beams and the wavelength of the signal beam. By setting incident angles of control beams appropriately, it can be determined whether a wavelength component of WDM signal is diffracted by the index grating or not. The component can be connected to the desirable spatial output port by arraying the gratings with different grating vector. We analyze the diffraction efficiency to investigate the wavelength selectivity of this interconnection and investigate the influence of the multiplicity of the signal beam on the diffraction efficiency. As the results, the wavelength selectivity 0.7[nm], which is equivalent to that of the conventional arrayed-waveguide grating, is achieved when the waveband is 500-520[nm]. Moreover the diffraction efficiency 0.055 is obtained when the degree of multiplexing is 50.