UC San Diego

Diabetes is an incurable metabolic disease, which has a number of devastating complications if left untreated. It is a leading cause of death worldwide and significantly impacts the live of the patient and their loved ones. Frequent blood glucose measurements must be taken to manage the disease, but conventional meters are invasive, painful, and create a potential avenue for infection. Although significant research effort has been made over the years to introduce and develop less invasive testing devices [Sensors. 19, 1151 (2019)], only one device, which is based on fluorescence technology, was able to obtain the U.S. Food and Drug Administration (FDA) approval (to our knowledge) [Sensors. 21, 6820 (2021)].

The effects that confound the noninvasive sensor stem from the complex measurement environment. The most successful approaches to navigating this sort of complexity involve the combination of multiple complementary spectroscopic techniques in addition to advanced analysis techniques. This combination holds the key to solving the problem of noninvasive blood glucose sensing.

The work shown in this dissertation analyzes different photonic components that can become an adequate candidate for such a system (e.g., a non-mechanical beam steering system, ring grating spectrometer, FTIR spectrometer, and side lobe reduction cascaded Bragg grating filters). While the application of broadband spectroscopy is nearly universal. The cascaded Bragg grating filters shown here can ensure that the spectra of the ring grating spectrometer is partitioned in a very careful way (resulting in sharp skirts). Moreover, the non-mechanical photonic beam steering could assist with optical coherence tomography (OCT). Finally, we propose a multifunctional photonic biosensor with information fusion. The device will leverage recent progress on integrated spectroscopy and fiber sensors to be accurate, portable, inexpensive, and extensible.