Usually high refractive indices ratio is believed the essential requirement to achieve wide band omnidirectional reflection with quarter-wave dielectric stacks, however in this paper, a high omnidirectional reflector with lower refractive indices ratio is achieved with a particularly designed dielectric stacks.

In this paper,the authors study the unchanged properties of π system,halfing,ring,field,monotonic system,λ system under a mapping f.

The quarter-waveplate can be made by cutting a fit section of PM fiber.

By using Jones matrix the expression of interference in the case of the imperfect quarter-waveplate was gotten.

Based on the coupled mode theory,by using the reversely recursive transmission matrix method,the switching characteristics of the λ/4 phase-shifted fiber grating and the influence of introducing chirp on the switching characteristics have been numerically studied when the reflection on the transmission facet is taken into account.

Based on the coupled mode theory,by using the reversely recursive transmission matrix method,the switching characteristics of the λ/4 phase-shifted fiber grating and the influence of introducing chirp on the switching characteris-tics have been numerically studied when the reflection of the transmission facet is taken into consideration.

The results indicate any elliptically polarized light can be compensated to become lineally polarized light throught λ/4 waveplate as long as the fast-axis(slow-axis) of λ/4 wave-plate and the long-axis(short-axis) of elliptically polarized light are in the same orientation,but partially polarized light cann t.

Right and left circularly polarized light generated by λ/4 wave-plates are experimentally performed, using He-Ne laser as a light source.

Thereinto,by λ/4 delayer,two bind lights not only exchange polarize aspect but also they transfers in a same fiber,the flex domino effect has not infection to transformer,so the extra disturbance around entironment bringing .