| The information age is upon us. We generate, process, store, display and transmit information in ever-increasing amounts. Sensing and measuring is one aspect of information generation that has become an increasingly important activity in the modern time. Sensors can be categorized in many ways. In the broadest context, sensors can be grounded into three categories - physical, chemical, and biological sensors. In the physical sensing field, optical sensors are powerful detection and analysis tools that have vast applications in biosensing, chemosensing, and acoustic sensing, etc. Research and development in optical sensors are motivated by the expectation that optical sensors have significant advantages compared to conventional sensor types, in terms of their properties, such as great sensitivity, wide dynamic range, electromagnetic immunity, electrical passiveness, multiplexing capabilities, etc. In recent years, research and development of miniaturized chip-scale optical sensing systems performing traditional laboratory measurements have received a growing interest. By leveraging advances in fabrication technologies, chip-scale optical sensors provide continued performance improvements over conventional sensing systems. These include greater sensitivity, smaller sensing area, shorter analysis time, reduced consumption of reagents, higher sensing throughput, multiple signals processing, and portability for field or point-of-care measurements. As a result, the recent literature is replete with examples of chip-scale optical sensing platforms developed to address a wide range of contemporary analytical challenges.;Although many chip-integrated optical sensing devices feature elegant miniaturization capabilities, the actual process of sensing quantitation is often achieved with far less grace, typically remain reliant upon bulky and cumbersome external interfaces for detection and signal processing which, at some level, diminishes the overall utility of these analytical devices while providing high sensitivity and array versatility. For example, most of the sensing configurations require bulk optics to guide light into devices and couple back into external optical detection systems. This configuration creates various limitations related to reliability, sensitivity, complexity, size, and cost. Especially, for some applications that have limited access to those larger external resources, it would be desirable to have signal processing and detection units and more functions to be co-integrated on one single platform.;Recent advances in semiconductor microfabrication have enabled high density co-integration of optical components and other functional devices. These integrated analysis systems offer substantial advantages for high versatility applications by enabling integration of optical sensing and other functions onto a single chip. While there are some reported examples of integrated optical sensing systems, most of applications are limited to use passive optical devices such as grating-coupled, interferometric, microresonator, waveguide-based, and optical fiber-based sensors etc. Meanwhile several attempts have shown a potential of the integration of active optical components with other functional devices. However, their integration process still suffer from high cost, complex packaging, and some difficulties related with dissimilar material integration. There still remain needs for efficient integrated systems that can combine different functional devices in a cost-effective and affordable way without sacrificing performance of each functional device.;This dissertation will investigate three integrated optical sensing systems in different sensing field - biosensing, chemosensing, and acoustic sensing - with the goal of contributing more functionality and miniaturization to the existing sensing devices that can be integrated together on a single sensing platform. |
