Experiment on Dual-Wavelength Method toward Spatial Mode De-Multiplexing with Volume Hologram in Optical Communication Wavelength Band

Abstract

In the mode division multiplexing transmission, the spatial mode de-multiplexing technique is required on the receive side. The volume holographic mode de-multiplexer (VHDM) provides the mode de-multiplexing function with a single device by utilizing angularly multiplexed volume holograms. However, it is difficult to apply the VHDM to the actual optical communication system because typical holographic mediums have no sensitivity in optical communication wavelength band. In this research, toward applying the VHDM to the optical communication system, we demonstrated the mode de-multiplexing by using the dual-wavelength method which allows us to record the volume hologram with the light of 532 nm in wavelength but use it to separate infrared readout beams of 850 nm in wavelength.