提出一种利用光频梳和可调谐半导体激光器提高台阶高度测量准确度的方法．通过将可调谐激光器锁定至光频梳，可对激光器的输出波长进行精确锁定与测量．基于可调合成波长链原理，利用锁定后的半导体激光器构建了一套台阶高度测量方案，该方案可消除合成波长误差对台阶高度测量不确定度的影响．采用一台可调谐半导体激光器和光频梳进行了5000S的连续锁定实验，结果表明，锁定后的可调谐半导体激光器的频率稳定度达1．8×10^-12．该方法的理论测量不确定度约为7．9nm，且测量结果可溯源至时间频率基准．%An improved method of step height measurement by optical frequency comb and tunable diode laser is presented. The tunable diode laser is phase locked to the optical frequency comb, so that the output wavelength of the laser can be locked and measured in a high accuracy. Based on the principle of variable synthetic wavelength chain, the step height can be measured by tuning the wavelength of the locked tunable diode laser. This method can be used to eliminate the effect of the synthetic wavelength error on the measurement uncertainty of the step height. The stability of the phase locked laser is tested by locking a tunable diode laser to an optical frequency comb for about 5000 s. It is shown that the frequency stability of the phase locked laser is 1.8 ×10^-12, The uncertainty of the step height measurement by this method is estimated to be 7.9 nm accordingly. Moreover, the measurement result of the step height can be traced to the time and frequency standard.
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