CMOS Integrated Optically Driven Sonic Fourier Transforms

Advances towards a Sonic Fourier Transform (SFT) computer is presented via an optically controlled monolithic single pixel implemented in a 130nm CMOS-MEMS PDK. Optical analog weight loading allows for massively parallel entire image throughput that is not possible with traditional serial pixel-per-pixel image loading. Images are loaded by variation in optical photodiode intensity that converts to the drive amplitude of ultrasonic waves generated by on-chip Aluminum Nitride (AlN) ultrasonic transducers. SFTs are achieved after the waves reflect on the silicon backside and enter far-field diffraction after travelling the entire wafer thickness. This work presents a single pixel with a photodiode, ultrasonic transmit, and ultrasonic receive is contained within the CMOS pixel die with external circuitry only used for digital control and pixel readout. The pixel ultrasonic drive is tuned with a variable input laser source that allows for up to 8 bits of resolution that can be implemented with standard image formats.