Abstract

The fiber loop mirror is an ideal device for investigating nonlinear switching by using the ultrafast Kerr nonlinearity of optical fibers, and a number of examples of its use have been published. These include pulse switching,¹ soliton switching,² and two-wavelength switching.³ The nonlinear phase shift depends on the product of the signal intensity and the fiber loop length; thus, to reduce switching intensities, we use long loops (~100 m). To improve the long-term stability of these devices, polarization-maintaining fiber (PMF) is used. Because the group and phase velocities are considerably different for the orthogonal polarization states of a PMF, in all the previous examples we ensured that the clockwise and anticlockwise signals traveled in the same polarization state within the fiber.

© 1990 Optical Society of America