ABSTRACT
Multimode and single-mode fibres have been developed to a high
degree of performance for communication and sensor applications.
Single-mode optical fibre has applications not only in very wide
bandwidth optical communication systems, but also in current rotation
monitoring and other interferometric devices. For such applications
the fibres operate with coherent polarized light. In order to obtain
measurements of the desired accuracy it is often essential that the
light has only one polarization or that the state of polarization is
controlled.
