Abstract

Single-mode fiber has been proposed as a solution to modal noise problems.¹ The SNR at the output of a modal noise-limited system is proportional to the number of modes, except for the true single-mode case in which there is only one path. Conventional single-mode fiber supports two orthogonally polarized modes. Practical fibers have imperfections such as ellipticity, bends, twists and internal stresses that cause birefringence, i.e., a difference in the phase velocities of the two polarizations.²

© 1981 Optical Society of America