Understanding polarization has become a necessity in today’s fiber optic communication systems and applications. One must understand how to characterize and handle the effects of polarization in order to maximize the performances of systems involving polarization-sensitive devices.
Polarization maintaining fiber (PM Fiber) is a special type of single mode fiber. Normal single mode fibers are capable of carrying randomly polarized light. However, PM fiber is designed to propagate only one polarization of the input light.
There are two polarization modes in a PMF: one polarized along the x-axis and the other polarized along the y-axis. The propagation constants of these two modes are different, and the polarization direction of a mode with the larger propagation constant is called the slow axis, as the phase velocity of the mode is slower than the other. And the polarization direction of a mode with the smaller propagation constant is called the fast axis.
The polarization mode polarized along the slow axis is usually well confined and robust against external perturbations; and thus is more often used.In polarization maintaining fiber, the polarization of linearly-polarized light waves launched into the fiber is maintained during propagation, with little or no cross-coupling of optical power between the polarization modes. This polarization maintaining feature is extremely important for some fiber optic components such as external modulators that require a polarized light input. For instance, in systems involving long-haul telecommunications the effects of the polarization mode dispersion (PMD) and polarization dependence loss (PDL) can result in very poor bit error ratios and shorter transmission distances.
Polarization maintaining (PM) fiber optic patch cord is built with polarization maintaining panda fiber and customization by FC/UPC or FC/APC connectors. The FC connectors can be supplied with wide key (2.14mm) or narrow key (2.02mm) width. The patch cord can be supplied with 250um bare fiber, 900um buffered fiber, 2.0mm or 3.0mm cable. TARLUZ PM patch cord features low insertion loss, high extinction ratio, and high return loss. The slow or fast axis can be aligned to the connector key upon request.
