Hydrogen is used as the main propellant for space shuttles, as an energy source in fuel cells, in oil
refineries, and for many other applications. Hydrogen is extremely volatile, easily flammable, and highly
explosive. Storage and handling of hydrogen is a challenging task and a good hydrogen sensor is highly
desirable. An ideal hydrogen sensor should be fast, reversible, highly selective, compact in size, easy to
fabricate, and cheap in price. Unfortunately such a sensor to date is not available.
In this paper we propose a multi-channel integrated optical sensor for detection of hydrogen. The sensor
consists of a high index waveguide on a low index substrate and uses Pd or Pd alloy thin film as the sensing
medium. Since a single channel hydrogen sensor will be affected by the presence of other gases and the
variations of temperature, humidity, and input power; a multi-channel sensing scheme and differential
measurements are proposed to correct for some of these effects. All the components of the multi-channel
sensor can be realized using planar technology and the complete sensor can be fabricated on a single chip.
The sensor is compact and the response time is expected to be very short. The concept of multi-channel
sensing presented in this work is very general and can be extended to other gas sensors as well.