Absolute distance measurement by chirped pulse interferometry using a femtosecond pulse laser.

We propose here a method for absolute distance measurement by chirped pulse interferometry using frequency comb. The principle is introduced, and the distance can be measured via the shift of the widest fringe. The experimental results show an agreement within 26 μm in a range up to 65 m, corresponding to a relative precision of 4 × 10^-7, compared with a reference distance meter.