1 572 nm narrow-band filter in laser telemeter

This paper introduces the primary purpose, characteristics and coating methods of 1 572 nm narrow-band filters in the laser telemeter. The multiple-cavity filters with low loss and high reliability have been developed using the computer coating optimization software. After the discussion of the technique problems, such as spectrum, temperature excursion and uniformity of the filters, experimental results of environment and characteristics tests are presented. Presently, these narrow-band filters （12 nm pass-band width）have been used in 1 572 nm laser telemeters. The effects are 11 km effective ranging distance at the precision of ±5 m and the frequency of (1±0.1) Hz．