Kyocera Corporation has recently shared details of a new underwater wireless optical communication technology. The demonstration took place in a freshwater laboratory and achieved data transmission speeds of 5.2Gbps over short distances. This rate comes from tests using Kyocera’s proprietary components designed for water environments. The company plans to showcase the system at CES 2026 in Las Vegas from January 6 to 9.
Underwater communication faces limits with traditional acoustic systems. Those methods cap at a few Mbps, which slows transfer of large files like video or sensor readings. Optical approaches use light to carry data, reducing attenuation compared to sound waves. Kyocera’s tests build on prior work, including 1.8Gbps indoor results in January 2025 and 750Mbps offshore trials in August 2025 near Numazu City, Japan. The latest demo focuses on lab-controlled conditions to validate speed gains.
The core of the system lies in the physical layer, or PHY, which handles data encoding and decoding. Kyocera developed original standards for this layer, separate from those used in wired or air-based wireless tech. Underwater settings require adjustments for light absorption and scattering by water particles. The PHY converts digital bits into laser pulses at blue wavelengths, optimal for water transmission. Tests ran over distances up to 15 centimeters, achieving the full 5.2Gbps rate.
A key upgrade involves expanding bandwidth to over 1GHz. This comes from an optical front-end circuit that matches the properties of semiconductor lasers. Standard underwater optical systems operate below 400MHz, limiting data volume. Kyocera’s circuit allows more signals per second, roughly 2.5 times the capacity of typical setups. In the lab, this supported transmission of high-definition video streams without dropouts. The lasers used are gallium nitride-based, efficient at producing blue light with low power draw.
The demonstration setup included transmitter and receiver units submerged in a tank of freshwater. The transmitter fired modulated laser beams toward the receiver. Data sources simulated inputs from underwater sensors, such as pressure and temperature readings. Video feeds mimicked those from autonomous underwater vehicles, or AUVs. Error rates stayed under 10^-9, standard for reliable links. Power consumption for the transmitter measured 5 watts, suitable for battery-powered drones.
Kyocera tested variations in water clarity to mimic real oceans. In clear freshwater, beam focus held steady. Adding mild turbidity, like from suspended silt, reduced range to 10 centimeters but kept speeds above 4Gbps. The system uses adaptive modulation to adjust pulse rates based on detected signal strength. This maintains connection as conditions change. Background light from surface lamps simulated sunlight, dropping efficiency by 20 percent, but narrow filters blocked it effectively.
The optical components include lenses with 90 percent coupling efficiency to guide light into the water column. Detectors on the receiver side employ avalanche photodiodes tuned for 450-nanometer wavelengths. These achieve quantum efficiency of 70 percent, converting photons to electrical signals. The signal processing chip handles 1GHz sampling, using field-programmable gate arrays for real-time error correction. Forward error correction codes recover up to 15 percent lost bits, common in optical links.
Compared to acoustic modems, which need hours for gigabyte transfers, this optical method completes them in seconds. Acoustic systems work over kilometers but at 100kbps rates. Optical limits distance to meters but excels in speed. Kyocera’s design targets hybrid use, pairing optical for close-range bursts with acoustic for positioning. In the offshore trials from August 2025, the prototype hit 750Mbps at 6.7 meters depth over 15cm to 1.5 meters, confirming scalability from lab to sea.
Environmental data from the Numazu tests included salinity at 35 parts per thousand and temperature at 25 degrees Celsius. Turbidity measured 0.5 NTU, low for coastal waters. Chlorophyll levels indicated minimal algae impact. The system ran unshaded under daylight, with transmission dropping 10 percent from glare. Shaded runs matched lab speeds. These metrics fed into the lab demo to refine parameters.
The PHY layer specifications define frame structures with 512-byte payloads and 64-byte headers. Synchronization uses preamble sequences of 16 symbols. Modulation scheme is on-off keying with pulse-position elements for higher rates. Error detection employs cyclic redundancy checks on 32 bits. The bandwidth expansion relies on multi-carrier techniques, dividing the 1GHz into 64 sub-channels of 15.625MHz each. This reduces interference from water ripples.
Receiver sensitivity requires -30dBm input for full speed, achievable at 20cm range. Transmitter output peaks at 100mW, within eye-safety limits for water. Thermal management uses heat sinks to keep lasers under 50 degrees Celsius. The full unit weighs 500 grams, fitting small AUVs. Power supply draws from lithium-ion packs at 12 volts. Integration with drone controllers uses Ethernet interfaces for data handoff.
Kyocera’s earlier 1.8Gbps indoor test used similar lasers but in distilled water. Offshore added salt and motion, cutting speed to 750Mbps. The 5.2Gbps lab result incorporates lessons from those, like improved beam collimation. Collimators reduce divergence to 1 milliradian, keeping the beam tight. Alignment tolerances allow 5-degree offsets without full loss.
For marine applications, the system collects data from multiple sensors. One scenario involves an AUV streaming 4K video at 30 frames per second, totaling 1Gbps raw. The optical link handles this burst, offloading to acoustic for storage. Another use inspects underwater cables, sending 100-megapixel images in under 30 seconds. Sensor arrays for temperature gradients transfer 10MB files instantly.
Kyocera plans distance extensions to 50 meters by 2027, targeting saltwater oceans. Current short-range suits dock-to-drone links or swarm robotics. Capacity goals aim for 10Gbps with next-gen semiconductors. Regulatory compliance follows ITU standards for optical wireless, with power caps at 1 watt average. At CES 2026, the booth in West Hall #6501 will demo the system live in a water tank. Visitors can send sample data packets and view metrics on screens. Adjacent exhibits cover AI depth sensors and millimeter-wave modules, tying into mobility themes. The event runs four days, drawing 130,000 attendees.
