Inventors:
John A. McNeil - Los Angeles CA
Robin A. Reeder - Arleta CA
Assignee:
Hughes Aircraft Company - Los Angeles CA
International Classification:
G02B 2744, G01J 318, H01S 310
Abstract:
A method and improved apparatus for aligning a diffraction grating, as, for example, one used in tuning the output of a laser. The total angular misalignment. epsilon. between the incident and diffracted beams is a function of three angles: the tuning angle. theta. 16, the angle of tilt. beta. between the plane of the grating 15 and the tuning rotational axis, and the angle. alpha. between the grating lines and the projection of the turning rotational axis in the plane of the grating 15. The present invention provides a method of aligning the diffraction grating so that the residual alignment error is very small over the desired range of tuning angle. theta. 16, by adjusting only. alpha. or only. beta. to zero at two reference tuning angles. theta. sub. 0 and. theta. sub. 1. Knowledge of the value of either. alpha. or. beta.