Polarization dependence of polarization-maintaining fiber couplers based on intensity transmission matrix

In order to effectively describe the relationship between beam splitting ratio, extra loss of polarization-maintainning fiber and polarization state, a new concept of intensity transmission matrix was proposed. The new theory can refine the expression equation including intensity transmission matrix parameters, extra loss and beam splitting ratio with different polarization. The curves of extra loss, beam splitting ratio with 45°circularly polarized light and eight intensity transmission matrix parameters was included and the correctness of intensity transmission matrix was validated. The results show intensity transmission matrix has important influence for the description of polarization characteristics of polarization-maintaining fiber couplers.