What is Polarization Maintaining(PM) fiber?
Theoretically, the fiber is a circular core which should not produce birefringence, and the polarization state in such a fiber will not change during transmission. In practice, there is always some external forces or other reasons which makes the fiber uneven or curved, and will cause a small amount of birefringence. When the fiber is subject to any external interference, such as wavelength, bending of the fiber, temperature and other factors, the polarization state of light will become chaotic when transmitted in polarization-maintaining fiber.
Polarization Maintaining Optical Fiber (PM Fiber) is such a specialty fiber with strong birefringence that is generated by the design of optical fiber geometry. It can effectively solve the problem of polarization state change by eliminating the effect of stress on the polarization state of incident light. If the polarization of the light incident on the fiber is aligned with one of the birefringence axes, the polarization state will remain even if the fiber is bent. This polarization maintaining feature is extremely important for some special applications that require a polarized light input.
How does the polarization maintaining (PM) patch cord work?
Polarization maintaining(PM) patch cord maintains the coupling alignment of two Polarization modes by precise connector keys. Compared with the traditional optical fiber patch cord, the PM optical fiber patch cord has the advantages of polarization-maintaining optical fiber transmitting polarized light signal, keeping the direction of linear polarization unchanged, improving the coherent signal-to-noise ratio, and realizing high precision measurement of physical quantity.
The polarization maintaining connector is an important component of two polarization maintaining fiber coupling, which ensures that the polarization mode of two PM optical fibers maintain the original polarization state of polarized light, and maintains a high extinction ratio for transmission. This requires precise docking of the slow or fast axes of the two fibers to minimize the θ angle error. By aligning the polarization direction of the polarized light with one of the axes, the polarization component assigned to the other axis is small, thereby maintaining the polarization state of the transmitted light. The polarization Angle and extinction ratio reflect the degree of polarization.
360° ferrule rotation adjustable Polarization Maintaining(PM) optical fiber connector
To meet the requirements of some special applications, HYC has developed a new type of polarization maintaining connector. HYC’s exclusive patented design of this polarization-maintaining connector has a 360° ferrule adjustable. During the process of assembling, the polarization axis of fiber is aligned with the connector key by rotating the ferrule until the polarization axis is aligned with the connector’s keyway. Compared with the traditional fiber adjustment method, it takes a shorter time to operate, which greatly improves the assembly efficiency. The polarization maintaining angle can be controlled within ±1°, and the high extinction ratio is maintained above ≥25dB.
PM fiber patch cord products have the advantages of high precision, low loss, ultra-high extinction ratio, convenient manufacturing technology, high efficiency, higher maneuverability and patent protection, etc. They are widely used in many fields such as aerospace, navigation, unmanned driving system, communication, highly sensitive interferometer, poly-deviation wavelength division multiplexer, and other fields.