Fiber Optic Rotary Joints in the Deep Sea Submersibles

Fiber Optic Rotary Joints in the Control Systems of Deep Sea Submersibles

When the submersible works, the operator needs to send information back to the control room of the mother ship, including the underwater camera signals, sonar image signals, time-division multiplexing multi-channel control signals, and all kinds of information from the computer in the submersible. At the same time, the operator shall remote control the submersible, including the control of its motion, position and the actions of the manipulator. Therefore, the control system needs to be equipped with multi-channel fiber optic rotary joint. Things will become complicated, as long as it involves the installation of the slip ring. Because compared with the fixed line, the rotary transmission of signals will subject to certain loss or other factors.

In order to ensure that the quality of image transmission reaches the national industrial television standard during the releasing and rewinding of the optical cable, JINPAT Electronics has adopted many corresponding measures in the development of fiber optic rotary joint. For example, square wave frequency modulation (SWFM) image transmission is adopted to reduce the effect of additional modulation caused by insertion loss change on baseband image transmission during slip-ring rotation. After adopting a series of measures, when the fiber optic rotary joint runs at 80rpm, its maximum insertion loss is 10dB, and the maximum wave momentum attenuation is 8dB after a rotation cycle. The performance is excellent.