When light is coupled into or out of an optical fiber through a normally cut end face, reflection may set up disturbing standing waves. They can be avoided by a slight tilt (≃ 12°) of the end face of the fiber and a corresponding inclination of the fiber axis. Residual reflections of -58 to -68 dB are obtained.
© 1980 Optical Society of America
R. Ulrich and S. C. Rashleigh, "Beam-to-fiber coupling with low standing wave ratio," Appl. Opt. 19, 2453-2456 (1980)