Silicon photomultipliers (SiPMs) are on the verge of revolutionizing all low light sensing and photon counting applications. The combination of low cost, compact size, and miniscule power consumption offers an attractive replacement for expensive, bulky, and power-hungry photomultiplier tubes (PMTs). SiPM laboratory setups typically include a bench full of heavy test equipment. The associated cost, size, weight, and power (c-SWaP) of this additional equipment present many practical challenges to the deployment of SiPMs, particularly in airborne and space missions.
Many applications benefit from a large tiled array of SiPMs. However, a large SiPM array presents a challenge in proper signal conditioning and handling large volumes of data. The key to solving this challenge is a complete read-out integrated circuit (ROIC) that takes the quantized analog signal from the SiPM array and converts it into useful digital data for the user. This ROIC not only manages the SiPM array data but does so in a manner that significantly reduces the associated c-SWaP from a benchtop solution, a key requirement for practical SiPM deployment.
The ultimate goal of this proposal is a fully integrated ROIC that interfaces to a SiPM array and is readily adaptable to both airborne and space deployed systems. The objective of Phase I is to develop the requisite components of a ROIC for photon counting and to assemble these components into a single channel of the ROIC. A test chip will be developed in Phase I to mitigate the risk of subsequent phases. This test chip will contain the relevant ROIC components, as well as a single channel of the ROIC, and will be designed, laid out, fabricated, and characterized in the Phase I effort.
Potential NASA applications primarily center around LIDAR, which is expanding into a wide variety of uses. NASA has significant requirements for the use of LIDAR systems, an example of which is the CALIPSO mission for studying clouds and atmospheric aerosols. The Freedom Photonics SiPM ROIC will enable and enhance the miniaturization of LIDAR to the point that it can be easily mounted on a drone. The cost of airborne LIDAR surveys will be significantly reduced by moving to a drone platform.
There is great interest in using silicon photomultipliers (SiPM) in many low light sensing and photon counting applications, such as:
Airborne LIDAR surveys benefiting government agencies. For example, the USDA can use drone mounted LIDAR to optimize fertilizer and pesticide application to farmland.
There are also significant commercial applications for this product. By far the largest commercial market that has a need for the ROIC product developed by Freedom Photonics is medical imaging.