Abstract: A solid-state oxygen microsensor which measures the potential difference (EMF) generated by two spaced apart electrodes deposited on a solid oxygen ion conducting electrolyte and located in a known and preferably constant temperature gradient in the same ambient atmosphere. Output voltage of the sensor is proportional to the temperature gradient established across the electrodes and the unknown oxygen partial pressure of the ambient atmosphere. The solid-state oxygen microsensor is useful for application to systems such as combustion systems to maintain and improve combustion efficiency levels and exhaust gas cleanliness.

Abstract: A piezoresisitve pressure sensor having a diaphragm of silicon nitride with a stressed resistor under the edge of the diaphragm in a single crystal supporting wafer. The signal is derived from the stress in the silicon where the diaphragm attaches to the edge of the opening etched through the silicon.

Abstract: An intravascular catheter tip fiber optic pressure sensor wherein a lens element at the end of the fiber optic collimates the light emanating from the fiber and directs the light in a column towards a closely spaced reflecting diaphragm. The diaphragm is pressure responsive and modulates the focal length of the lens-diaphragm-mirror combination. Three optic fibers traverse the length of the hollow catheter tube, one carrying transmitted light to the tip, one carrying the reflected light from the diaphragm (i.e. the signal), and the third fiber carrying a reflected reference light. The reference detector provides a signal level to control the level of intensity of the light source.

Abstract: In an optical absorption gas sensor there is a practical problem of obtaining a sufficiently long optical path necessary to provide the required sensitivity within a compact space. In the present invention the path length can be multiplied to about 2 meters in a hemispheric like chamber having a radius about 8 cm. A novel, compact and inexpensive cell structure for increasing the optical path length by multiple reflections is provided.

Abstract: In thin film optical systems including thin film optical waveguides, of such materials as Nb.sub.2 O.sub.5, it is desirable to fabricate thin film lenses. One of the types of lenses which can be made is the step-in-thickness type. This type of thin-film lens can be fabricated by plasma etching through a photoresist mask in such materials as Nb.sub.2 O.sub.5 and Ta.sub.2 O.sub.5. Plasma etching yields an etch wall with smooth steep sides which is important for good quality thin-film lenses; however, the etch rate is too variable for reproducible etch depth based upon etch time, and the bottom of the etch is very rough, causing excessive scattering loss. It has been found that a sandwich-like structure of Nb.sub.2 O.sub.5, TiO.sub.2 and Nb.sub.2 O.sub.5 provides an improved arrangement in that a good control of the etch depth and a smooth flat bottom in the etch areas have been achieved by introducing the layer of TiO.sub.2 as an etch stop.