The coupling of a semiconductor laser as a coherent well-polarized source to birefringent polarization-maintaining fiber is an important step in exploiting the unique characteristics of this waveguiding medium. The total light output of most semiconductor lasers is relatively poorly polarized yielding extinction ratios of the order of 10–12 dB. We wish to report here alignment and coupling characteristics of a linear polarized single-mode semiconductor laser to a highly birefringent fiber for polarization-maintaining purposes. We have observed extinction ratios in excess of 20 dB between the two axes of the fiber using a simplified alignment method which utilizes the natural polarization of the laser and the relatively narrow acceptance angle of the fiber as a spatial filter. A simple method of alignment and permanently attaching the fiber to the laser is described.
Ronald O. Miles, A. Ceruzzi, and M. J. Marrone, "Attaching single-mode polarization-preserving fiber to single-mode semiconductor lasers," Appl. Opt. 23, 1096-1099 (1984)