Wireless Photonic Sensors with Flex Fan-Out Packaged Devices and Enhanced Power Telemetry

The objective of this paper is to demonstrate flex-embedded and surface-assembled photonic devices, inductive telemetry, and passive integration to form next-generation miniaturized biophotonic sensors. A hybrid combination of embedding and surface-assembled devices on flex is pursued to reduce the lateral and thickness dimensions of biophotonic systems. Embedding of premanufactured discrete passive devices is demonstrated by inserting in cavities, followed by printed fan-out connections to form the bridge connects between devices and other system components. Initial prototypes showed functional response to color shifts and reliability under bending loads on tissue phantoms. Measurements also confirmed responses to muscle activity as seen through changes in the backscattered light intensity during fist-closure with human subject hands. Initial bending test and reliability after water immersion indicate the stability of the chosen material systems towards flexible and wearable applications. This system concept can eventually be integrated with other system components such as RF transceivers for data telemetry, leading to completely autonomous wireless photosensors for wearable and implantable systems.