Development of homodyne interferometers for space applications.

At the University of Birmingham we have been developing compact homodyne interferometers for our STFC-funded research program in experimental gravitation. This work has resulted in the development of a novel angular interferometer that we are now adapting for the angular readout of our room temperature and cryogenic torsion balances. We have also applied for 2 patents on the optical design of the interferometer and developed a compact interferometer for commercialisation. Support for this work has come from the STFC Follow On Fund and also from University Knowledge Transfer and Development funding. The original STFC grant, prior to the Follow On Fund, was an Innovative Technology grant aimed at developing an interferometer for drag-free satellite control. We would like to continue this research theme by investigating the application of homodyne interferometers in space missions and in the space environment in general. Homodyne interferometers are promising devices for space applications as they can be simple, compact and contain no active modulation systems and associated power supplies. These advantages carry with them the possibility that they can have lower mass and more reliable than the heterodyne systems and these are clearly desirable features for space applications.However, in principle, homodyne interferometers can have as high resolution and as good linearity as heterodyne systems.