Fiber optic polarizers (FOP) are placed inline to improve the extinction characteristics of fiber optic cable. They allow the transmission of only one polarization, blocking light in unwanted polarization states. Fiber optic polarizers are used because degradation in polarization extinction can cause noise interference and limit the performance of the entire fiber optic system.
Fiber optic polarizers are available in a two cable types, single mode and multimode. Single mode devices have an optical fiber that will allow only one mode to propagate. The fiber has a very small core diameter of approximately 8 µm. It permits signal transmission at extremely high bandwidth and allows very long transmission distances. Multimode fiber optic cable supports the propagation of multiple modes. They typical have core a diameter of 50 to 100 µm with a refractive index that is graded or stepped. They allow the use of inexpensive light emitting diode (LED) light sources and connector alignment and coupling is less critical than single mode fiber. Distances of transmission and transmission bandwidth are less than with single mode fiber due to dispersion.
Fiber optic polarizers (FOP) are placed inline to improve the extinction characteristics of fiber optic cable. They allow the transmission of only one polarization, blocking light in unwanted polarization states. Fiber optic polarizers are used because degradation in polarization extinction can cause noise interference and limit the performance of the entire fiber optic system.
Fiber optic polarizers are available in a two cable types, single mode and multimode. Single mode devices have an optical fiber that will allow only one mode to propagate. The fiber has a very small core diameter of approximately 8 µm. It permits signal transmission at extremely high bandwidth and allows very long transmission distances. Multimode fiber optic cable supports the propagation of multiple modes. They typical have core a diameter of 50 to 100 µm with a refractive index that is graded or stepped. They allow the use of inexpensive light emitting diode (LED) light sources and connector alignment and coupling is less critical than single mode fiber. Distances of transmission and transmission bandwidth are less than with single mode fiber due to dispersion.
Some fiber optic polarizers can be pigtailed into a cabling system. These polarizers often referred to as inline fiber optic polarizers, offer high extinction ratios, low insertion loss, and high return loss performance over a wideband wavelength range in a compact inline package. Extinction ratio is the ratio of the power of a plane-polarized beam that is transmitted through a polarizer as compared with the transmitted power when the axis of the polarizer is perpendicular to the beam's plane. Insertion loss refers to the attenuation caused by the insertion of an optical component. Return loss is the ratio of reflected power to incident power. It is a measure of the amount of reflected power on a transmission line when it is terminated or connected to any passive or active device.
Fiber optic polarizers are used in a wide range of applications including optical transmission and communication systems, various sensors and instruments, and erbium-doped fiber amplifiers (EFDA).
