Remote Control of Underwater Drone by Fiber-Coupled Underwater Optical Wireless Communication

In this research, we prototyped an underwater optical wireless communication device that directly transmits and receives optical signals at the end of an optical fiber, and try to remotely control an underwater drone by the device. Since the area of the optical fiber end face is very small, lights emitted by multiple laser diodes are guided into one optical fiber with lens to brighten the light from the end. In addition, a plastic optical fiber with a large core diameter is used for receiving many optical signals in the device. First, the profile of the transmission beam and receiving beam, and the difference in output intensity from each port of the beam combiner were confirmed. Based on these results, the orientation of the end of the optical fibers are adjusted and installed on the bottom of the pool. In the remote control of the underwater drone equipped with a small optical wireless communication device, it was possible to operate with the poolside controller while checking the image of the onboard camera via optical wireless communication. The area where the drone could be controlled was almost the entire pool.