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AssigneeZhejiang Sci-Tech University
InventorsBenyong Chen, Jiandong Xie, Liping Yan
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A reference laser beam locked to a femtosecond optical frequency comb is modulated through a high frequency electro-optic phase modulator, and laser sidebands with equal intervals are generated. Beat frequency is performed on the sixth-order sideband and the frequency sweeping laser beam, a beat signal and a frequency sweeping signal source are down-mixed to generate a difference frequency signal, and the difference frequency signal is locked to a reference clock through a digital phase detector and a PID controller. The frequency sweeping laser beam is locked to reference laser beam with a dynamic offset frequency under the closed loop control, and sinusoidal frequency sweeping is simultaneously performed together with the frequency sweeping signal source. The locked laser beam is used for absolute distance measurement, and a distance to be measured is obtained according to the synthetic wavelength transition theory.
A sinusoidal frequency sweeping interferometric absolute distance measurement apparatus with dynamic offset frequency locking, comprising a reference laser (1), a first optical fiber beam splitter (2), an optical fiber beam combiner (3), a high frequency electro-optic phase modulator (4), an orthogonal optical fiber beam combiner (5), a coupler (6), a locking controller (12), a femtosecond optical frequency comb (13), a first high frequency amplifier (14), a high frequency clock source (15), a high frequency photodetector (16), a second high frequency amplifier (17), a frequency mixer (18), a third high frequency amplifier (19), a frequency sweeping signal source (20), a digital phase detector (21), a PID controller (22), a frequency sweeping laser (24), and a second optical fiber beam splitter (25);
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