Explain an all-optical tunable detention in gas laser based on wavelength conversion wavelength reconversion. The use of stable, calibrated optical reference cavities to equipping interferometer users with more exactly. Various resonance wavelengths of cavity were resolved by frequency measurements in a vacuum by use of a gas laser comb followed by corrections to account for atmospheric pressure and cavity temperature. A purpose of a new stable cavity is discussed that allows for the longitudinal mode index to be determined by difference-frequency measurements between the S and P polarized modes. For a wide range of signal pulse interval (ps to 10 ns), an output signal wavelength and bandwidth that are the same as that of the input.