Wavelength Calibration for an External Cavity Diode Laser Using a Polynomial Dual-Cosine Model

A polynomial dual-cosine model is proposed for the wavelength calibration of an ECDL (Santec-TSL710-O-band). An analysis of the ECDL’s measured spectral data demonstrates that the polynomial dual-cosine model reduces the relative wavenumber fitting residuals by a factor of five within a scanning range of 30 cm−1. The experimental results of broadband temperature measurement (700~1600 K) in the tube furnace confirm that the proposed model successfully reduces the maximum temperature relative error from 6.7% to 2.3%. The wavelength calibration model effectively promotes further research on the broadband absorption spectroscopy thermometry method and its application in the temperature diagnostics of aeroengine combustors.