Abstract: To reduce the long-term frequency drift, CW laser modulation free frequency stabilization is realized based on precision wavelength meter by means of computer control. In order to lock the laser’s frequency, the computer extracts the data from wavelength meter, then calculates the feedback voltage with PID algorithm to adjust the cavity length. This simple method can be applied to any given wavelength within spectral range of a commercially available laser, and can lock the laser to any absolute frequency within its tunable range. Using this method, a 631nm external cavity diode laser was stabilized with frequency bandwidth is 7.4 MHz for an hour, and long-term frequency drift is measured to be.

Key words: long-term drift