Ultrastable wavelength calibration reference constructed from an athermal Mach-Zehnder interferometer filter

A simple wavelength reference was constructed by illuminating an athermal silica-based Mach-Zehnder interferometer filter with a broadband light source. The nonlinear wavelength-voltage response of a Fabry-Perot tunable filter can be calibrated by using the constructed wavelength reference. The maximum wavelength deviation of the calibrated system with the Fabry-Perot tunable filter is 6times10^-5 nm over a monitoring period of 12 h