The chemical composition of a (SiO2)x(Si3N4)1−x film produced by ion beam sputtering was precisely controlled by the ratio of O2 and N2 flow rates under a discharge current kept constant to within an accuracy of ±0.05 A. The reproducibility of the refractive index was improved to ±0.01. This film was applied to form antireflection coatings with extremely low reflectivity on facets of 830-nm AlGaAs double heterostructure lasers. The minimum reflectivity was 6.8 × 10−5, and a reflectivity of 1 × 10−4 was achieved reproducibly. Experimental studies show that antireflection coatings are effective for suppressing the interferometric light output variation of composite cavity lasers.
© 1990 Optical Society of America
Original Manuscript: November 17, 1989
Published: December 1, 1990
Yoshitada Katagiri and Hiroo Ukita, "Ion beam sputtered (SiO2)x(Si3N4)1−x antireflection coatings on laser facets produced using O2–N2 discharges," Appl. Opt. 29, 5074-5079 (1990)