ABSTRACT
Integrated optical sensors present one of the modern and promising approaches to the development of chemical sensors, including humidity sensors. It was established that planar integration is a way to allow enhanced functionality devices to be made, in which microfluidics and multiple sensor elements can be incorporated into a single device, that is, integrated optical sensor. It is believed that this approach provides a superior degree of compactness, stability, and reliability. In addition, integrated optics allows for an on-chip thermal compensation. One should note that, in general, integrated optical sensors (IOS) are a branch of micro-optics and integrated optics (IO), which emerged from the successful techniques of microelectronics together with micromechanics and other microtechnologies. These devices have a common physical operating principle, in that they all operate by having a dielectric waveguide in which the propagating mode is allowed to partially interact with the measurand, and where the optical path change associated with that interaction is measured. Readers of the present chapter will find consideration of basic principles of integrated optical sensors design and fabrication, including description of materials, elements of IOS, and processes usually used in IOS fabrication. Approaches that have been used to design and fabricate integrated optical humidity sensors are also considered in the present chapter.
