Free space laser communication system based on orbital angular momentum of light beams

Abstract

The invention relates to a free space laser communication system based on the orbital angular momentum of light beams, which belongs to the technical field of optical applications. The free space laser communication system consists of an optical fiber closely arranged laser, four convex lenses, two polarizers, a space optical modulator, a pinhole diaphragm, a beam expansion system, a composite binary amplitude grating and a CCD detector. The free space laser communication system takes the optical fiber closely arranged laser with gate control as a light source, designs a phase diffraction grating loaded onto the space optical modulator according to the distribution of the light beams emergent from the optical fiber closely arranged laser, and leads all the light beams to respectively havedifferent diffraction orders and be positioned on a central shaft of the system, thereby constructing a central diffraction light beam carrying gate information of the optical fiber closely arranged laser. When the system works, the gate control is carried out on the optical fiber closely arranged laser according to data to be transmitted for realizing the modulation loading of the data to be transmitted; and the light beams carrying data information utilize the composite binary amplitude grating to detect the orbital angular momentum state of the light beams at the receiving end of the system after transmitting for a certain distance in free space, thereby completing the demodulation of the data transmitted by the communication system.

Description

technical field [0001] The invention relates to a system for realizing the transmission of data information of 8 bits or more in free space by using the mode division multiplexing technology based on the orbital angular momentum of light beams, and belongs to the field of optical application technology. Background technique [0002] Multiplexing is a technology that can simultaneously transmit multiple signals in the same transmission medium. It enables multiple terminals to share a high-speed channel, thereby achieving the purpose of saving channel resources and improving the utilization rate of communication lines. Such as wavelength-division multiplexing (Wavelength-Division Multiplexing, WDM), is to transmit two or more signals of different optical wavelengths in the same optical fiber at the same time, so that multiple signals can be transmitted in one channel at the same time. [0003] Similar to this, we propose Mode Division Multiplexing (MDM) based on beam orbital a...

AI Technical Summary

Problems solved by technology

However, this method uses four independent semiconductor lasers as light sources, and the parallel accuracy of the output beams is difficult to guarantee, and limited by the dimensions of the lasers, it is difficult for this device to further increase the number of multiplexed orbital angular momentum states.

Images