Deep Ocean Fiber Integrated Gigahertz Ultrasonic Sound Velocity Mapper

This effort will develop a long-term stable acoustic sound velocity sensor with a small form factor, on a thin diameter format to enable simultaneous measurement of sound velocity profiles along an ocean column. The work will develop 0.2 to 2 GHz ultrasonic transducers that can be used to transmit and receive pulses along a water gap. The gaps are large enough to enable easy access to surrounding waters. The ultrasonic pulse path includes UV lamp surface that provides photons to prevent biofilm formation in the water sampling volume. The devices will be placed on a thin fiber with conducting wires that can be used to communicate with sensors with high spatial density along the fiber cable, which can reach 1–2-kilometer depth. The fabricated sensor will be tested in a lab environment to optimize the sensor parameters. Custom CMOS chips will be designed and fabricated to control the ultrasonic transducers. The testing of the sensor at 300meter depth will be done in conjunction with the Scripps Institute oceanography team. The data from these tests will determine operational parameters such as sensitivity, variance amongst sensors, the speed of readout of the sensor array, power consumption, and the limit of depth at which the ocean sound velocity sensor can be operated.