Study On Laser Wavelength Measurement Based On Dual Fabry-P(?)rot Etalons

An all-fiber instant laser wavelength measurement scheme based on dual etalons and an optical linear filter is proposed and demonstrated.The linear filter is utilized for the coarse measurement while the F-P etalons are employed for the fine measurement.By slightly tilting the refractive angle of one etalon,its phase and waveform can be tuned,and then combined with the waveforms of reference etalon,a compensation measurement which covering the whole range without any dead zone can be achieved.By discussing the combination of different phase shift quantities,Various wavelength determination criteria are also discussed for different etalon phase offsets,which can achieve the measurement accuracy of ±1.38 pm.The system exhibits many advantages such as compact structure,low cost and fast response.In this paper,the advantages and disadvantages of various methods of measurement have been summarized and compared based on the analysis of domestic and international laser wavelength measurement systems,and puts forward the wavelength measurement scheme based on dual F-P etalons.The Angle-sensitivity of the Fabry-Perot interference fringes and the Free Spectral Range are described in detail.The paper analysis the material properties of the solid cavity F-P etalon and the optical structural characteristics of the collimator in detail.The detailed measurement of the overall optical path frame of the wavelength measurement is made,including the rough measurement of the linear filter and the accurate measurement of the dual F-P etalons.Then introduce the parameters of each device and the realization of the hardware circuit.The wavelength measurement method of two different combinations is put forward.Having analyzed the characteristics of the wavelength response curve of the two combination methods,a wavelength determination criterion and the optimal wavelength measurement scheme are proposed after analysis the waveform dead zones of the different phase shift.According to measurement data,it shows the accuracy of the wavelength measurement system can reach ±1.38 pm within the range of 1520nm-1570 nm,and the stability of the wavelength measurement device was also tested.