Conclusion

Many other applications have recently been studied, as

- speed measurement (see Erskine & Holmes, Nature 377, 317 (1995) ).

- measurement of chromatic dispersion in optical fibres.

- measurement of polarisation mode dispersion in optical fibre.

- measurement of stray polarisation coupling in optical fibres (see P.Martin et al., Proc.SPIE 1585, 173 (1991) ).

I hope that this brief and elementary overview can stimulate the students to invent new applications, as this subject has many possibilities of development.