Analysis of circular-polarization electrooptic amplitude modulators

An analysis of electrooptic (EO) amplitude/IM modulators of light having the form of circular polarizer-sample-circular analyzer (CPSA) systems is presented. On the assumption of nonideal components, with the sample being a linear EO crystal, principal characteristics and performance parameters of the above modulators are derived and investigated as to the effect of azimuthal misalignments θ in the crystal birefringence axes. The so obtained results are compared with those drawn from the study of linear-polarization EO amplitude modulators structured as linear polarizer-sample-linear analyzer (LPSA) systems in their optimized variety (45°-CLPSA modulators). From this comparison, it is found that a CPSA modulator in its optimized configuration (ACPSA modulator) is superior in EO-modulation sensitivity and considerably more stable against misalignments θ than its 45°-CLPSA counterpart. On the other hand, both kinds of modulator exhibit identical behavior as regards harmonic distortion and maximum-nonlinearity parameters