There are several potential advantages to using highly coherent single mode laser sources in optical fibre gyroscopes. These include the potentially high output power and the relative ease with which a single mode source may be modulated in both frequency and intensity. However most systems use incoherent (edge emitting LED's) sources to avoid the detrimental effects of coherent backscatter. In this paper we demonstrate some techniques whereby the effects of discrete reflections and backscatter may be minimised resulting in gyroscope noise levels of approaching 0.1 degrees/hr/hz.
I P Giles,
"Coherent Sources In Optical Fibre Gyroscopes", Proc. SPIE 0468, Fibre Optics '84, (15 August 1984); doi: 10.1117/12.941663; https://doi.org/10.1117/12.941663