This Small Business Innovation Research (SBIR) Phase I project will advance the proposed SMART (Sensor Monitoring and Reliable Telecommunications) prototype, designed as a best-in-class pressure, temperature, and seismic sensor system to be incorporated into new global submarine fiber optic cable networks. The expected commercial impacts are significant, as the customer base for SMART technology includes commercial submarine cable suppliers, government monitoring agencies, scientific consortia and agencies, and internet content providers. The development and deployment of SMART will enhance scientific understanding of Earths oceans, seafloor, and subsurface via a fundamentally new approach to long-term subsea sensor network deployments. SMART will therefore provide essential new data to reduce disaster risk and improve global climate understanding, thereby reducing societal and environmental vulnerabilities to these long- and short-term threats.The intellectual merit of this project is to develop the first integrated SMART prototype system. This innovative real-time deep ocean monitoring technology will catalyze fundamental improvements in Tsunami Early Warning (TEW), Earthquake Early Warning (EEW), global climate monitoring and telecommunications resiliency. The innovation is to tightly integrate sensors into the amplifiers (repeaters) used to boost signals in the optical fibers. Commercial off-the-shelf (COTS) components will be utilized for nearly all physical elements of the system. The sensor assembly includes a 3-axis accelerometer, absolute pressure gauge, and temperature sensor, integrated with data acquisition circuits with suitable dynamic range and precision, a common communications module, an interface suitable for fiber optic cable spans up to 120 km in length, software and firmware necessary to support the data path, an isolated power source, and precision timing. The SMART repeater design is modular, allowing different sensors, adaptation to different repeater housings, or use as a standalone unit. Technical hurdles to be addressed include hardware development and integration, software development, data acquisition and processing, power management, communications bandwidth, and delivery of precision time and frequency references.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.