In this paper,polarization switching performances and polarization bistability performances in VCSEL subjected to optical feedback had been investigated.

Based on the rate equations describing the dynamic characteristics of the master and slave vertical cavity surface emitting laser (M-VCSEL,S-VCSEL),under the modulation of pulsed bias current,the polarization characteristics of M-VCSEL output and the polarization switching performance of S-VCSEL subjected to optical pulse output from the M-VCSEL have been investigated.

The theoretic transfer function of the filter made of N stage HBFs, and the expression are obtained when N is 1, 2 or 3; the polarization independence of the filter is analyzed, and the relation between the frequency response and the parameter of filter such as the length, beat length of HBFs and the angles between HBFs is studied; finally, some experimen.

Then the polarization independence of nonreciprocal waveguide was realized.

A novel structure of polarization independent, in line magnetic optical isolator was presented.

A novel configuration of 2×2 all optical polarization independent bidirectional fiber optical switch is presented.

Study on structure of polarization dependent isolators;