Short-Term Frequency Stability Measurement Of 2μm Solid-State Laser

The 2-micron laser is the safe wavelength band to human eyes. Laser Imaging Lidar, coherent Doppler Wind-profiling Lidar and Differential Absorption Lidar is an important research .The lamp-house of Lidar requires single longitudinal frequency, narrow linewidth and stable frequency. Short-term frequency stability of lasers effects lidar's measurement accuracy directly. So the measurement of short-term stability of the laser is quite essential.Theoretically, analyze the excellences and shortcomings among F-P interferometer method, heterodyne method and self-beat-frequency method in the short-term stability measurement. Point out that the methods above should be taken on. Preview the difficulties in the process of the measurement.We analyze the output power and power characteristic of the 2μm Tm,Ho:YLF microchip laser. We use self-beat of fiber delay method to measure the short-term frequency stability. Analyze the conditions, and the choice of the experiments also influence factor of measurement. Integrate the existing condition, we optimize experiment gradually. Also we do not have frequency spectrum analyzer, combine theoretics and experiment. We obtain the best result and complete the short-term frequency stability of 0.5μs~2.5μs. By changing the length of the optical fiber, we measured the relation between the relative frequency fluctuation and delay time. Frequency stability of the microchip laser is examined by the self-beating heterodyne detection method for several delay times between 0.5μs and 2μs.It is indicated that the spectral fluctuation is in proportion to delay time and the increasing rate is 1.48kHz/μs. Associative the measurement results and integral time, concluding the possible result of long integral time. Quality analysis the measurement error of short integral time. The result is, short-delay frequency stability would smaller then we measure now.