Prototype of Optical/Acoustic Hybrid Underwater Communication Modem DevelopedConducted ocean experiments as part of the Defense Equipment Agency's project

Shimadzu Corporation has developed a prototype of an optical/acoustic hybrid underwater communication modem. The prototype, which combines an underwater optical wireless communication modem manufactured by Shimadzu and an acoustic communication modem manufactured by another company, was developed under the Acquisition, Technology and Logistics Agency's FY2022 Bridge Research^*1 program and tested in a water tank and in the open sea from January to February last year. The demonstration experiment consisted of using an optical wireless communication modem for transmitting large amounts of data over short and medium distances under various conditions, including ever-changing depth, turbidity, and water temperature, and switching to an acoustic communication modem for underwater and long-distance communication where the effects of ambient light and turbidity are strong.
In the past, wired communication using cables has been mainstream for underwater communication, while acoustic wireless communication using sound waves was used in other cases. In the former, cables allow real-time transmission similar to that on land, but the resistance from ocean currents and other factors limit the activities of the ROVs (Remotely Operated Vehicles). The latter is used in AUVs (Autonomous Underwater Vehicles), but the communication speed is limited to several tens of kilobytes per second (kbps), making real-time transmission of large amounts of data difficult. To solve these problems, manufacturers and research institutes within and outside Japan have been developing underwater optical wireless technology that can easily increase communication speeds, but most of them use light-emitting diodes (LEDs) as the light source. The MC100 and MC500^*2 underwater optical wireless communication modems manufactured and marketed by Shimadzu use semiconductor lasers, which offer superior directivity and response speed.
Shimadzu plans to develop underwater wireless communication technology that can be used in security, marine resource exploration, offshore wind power and oil & gas installation and inspection, and fisheries(particularly aquaculture). Shimadzu will continue to promote open innovation for the implementation of this technology in our society in cooperation with domestic and international companies, research institutions, and local governments.

• *1 The Acquisition, Technology and Logistics Agency's system for linking promising basic research and technology to the research and development of equipment
  *2 The MC100 and MC500 utilize the results of research and development conducted with the Japan Agency for Marine-Earth Science and Technology (JAMSTEC) under the Acquisition, Technology and Logistics Agency's Innovative Science and Technology Initiative for Security.

Product Photo: MC500 Underwater Optical Wireless Communication Modem

Related links
https://youtu.be/5TvA29hn5-g
https://www.shimadzu.com/news/fmz1i00i-7c3rmr5.html
https://www.shimadzu.com/underwater/mc500.html