LASER LENGTH MEASURING APPARATUS

摘要

PROBLEM TO BE SOLVED: To realize a laser length measuring apparatus capable of easily performing a correction in the generation of a mode jump. SOLUTION: This laser length measuring apparatus using a semiconductor laser comprises a means for measuring a prescribed length by use of a wavelength oscillated by turning on a prescribed current and a reference scale; a storage means for storing the measurement result; and a comparative means for measuring the prescribed length by use of the reference scale by turning on the same prescribed current and comparing this measurement result with the measurement result stored in the storage means. When the comparison result exceeds a predetermined value, the generation of the mode jump in the laser is judged, and the predetermined value is added to or subtracted from the measurement result.