SBIR-STTR Award

This work proposed to utilize GHz CMOS integrated ultrasonic pulses to characterize the ocean water velocity. The sensors will be small chiplets, ~ 1 mm-cube volume, small enough to be placed inside thin plastic fiber which can be delivered into water from a small form factor delivery unit into water to very deep waters. The chipsets can measure salinity, temperature, sound velocity, water velocity, providing all the parameters needed to measure the ocean water velocity with high degree of accuracy. Furthermore, the spatial density of the sensors on the fiber can be high from every cm to every meter, providing a highly detailed mode of the velocity along the fiber length. Each sensor can provide the data every 100 microseconds, enabling 10-kHz bandwidth in reading each sensor. The power consumption is low, with ultralow power sleep mode per sensor, enabling a long lifetime persistent sound velocity mapping in deep ocean.

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.