Towards the realisation of a pressure sensor incorporating integrated optic waveguides

The authors report on the steps they have completed towards the development of a miniature pressure sensor incorporating single mode integrated optic waveguides. In this sensor, a Mach-Zehnder interferometer is fabricated on one side of the diaphragm. The pressure induced deflection of the diaphragm results in the differential phase modulation of light guided in the two arms of the interferometer. Interference between the lightwaves in the two arms produces the usual output intensity variation characteristic of two-beam interferometers. In the work described the authors use an alternative waveguide fabrication technology-flame hydrolysis-to fabricate low loss waveguides on the silicon diaphragm