Demonstration of an ultra-wideband wavelength self-adaptive and high-precision single-frequency laser linewidth measurement system.

An ultra-wideband wavelength self-adaptive and high-precision single-frequency laser linewidth measurement system (SFLLMS) is constructed. The SFLLMS enables parameter measurement of the laser in the wavelength range of 1-2.05 µm with a 9 Hz linewidth measurement resolution and ±45 Hz linewidth measurement accuracy. The wavelength measurement accuracy of the constructed system is ±0.008 nm, and it consumes less than 4.9 s for a single measurement. The wavelengths and linewidths of lasers in the 1 µm band with a center wavelength of 1064.5222 nm, the 1.5 µm band with a center wavelength of 1550.1973nm, the 1.94 µm band with a center wavelength of 1940.8327 nm, and the 2.05 µm band with a center wavelength of 2049.0460 nm were measured using the constructed SFLLMS. The wavelength measurement accuracy and linewidth measurement accuracy were calculated. The times for single linewidth measurement at different powers of the four lasers were also recorded.