The Study Onpolarization Difference Frequency Modulation All Stokes Parameter Measurement Methodin Optical Fiber Communication

With single-channel fiber-optic communication speed towards40Gb/s and above development, various nonlinear effects, polarization mode dispersion significantly enhanced, thetraditional shortcomings of encoding formats gradually emerged. Polarization coding has anatural balance of power, the polarization characteristics of good, small power costs and otheradvantages, it can greatly reduce the system’s non-linear effects, inhibit polarization modedispersion, reduce the error rate and improve spectral efficiency. Polarization coding is the useof polarization of light signals carrying information coding, the polarization informationacquisition is particularly important.Description of the beam polarization state of the most popular and most comprehensiveway is to use a set of physical parameters of the same dimension-Stokes parameters. We candeduce Jones vectors and the degree of polarization beam by the Stokes parameters. That is aslong as the measured Stokes parameters, we will arrive at any kind of mathematicalexpressions on this beam of light. Therefore, this article is based on photoelastic modulatorprinciple analysis, studied the polarization difference frequency modulation of Stokesparameter measurement method.The method of three photoelastic modulator (Photoelastic Modulator, PEM) are working onthree different frequencies slightly different values, then the difference frequencymodulating polarized light, the polarization information generated containing the lowfrequency components, and finally by lock-in amplifier can simultaneously achieve fourStokes polarization parameter measurements. This method not only retains the advantages ofthe original elastic light modulator polarization measurements,but it can also overcome the shortcomings of existing methods, such as an array of detectors can not be used effectivelycapture and high modulation frequencies. At the same time, this article gives the MATLABsimulation and experimental validation protocols. Through theoretical analysis, simulationand experiment prove the feasibility of this method. Finally, the paper has carried on the erroranalysis.Measurement error within1%, which can meet the measurement requirements.Measuring devices used in polarization encoding, through accurate measurement ofpolarization, polarization beam coding communication is realized.