The Research On Loss And Influence Factors Of Single-mode Optical Fiber Connectors

Today, the optical fiber communication is developing very fast, and the use of optical fiber is also increasingly widely. So the optical fiber connector which is used to connect fiber is an important part of fiber optic network. Insertion loss and return loss as two important parameters of optical fiber connector will produce great influence. Analysis of the influence of different factors on the insertion loss and return loss degree and rule, proposing the improved method and technology are the main research direction of this paper.First, this paper establish docking model of optical fiber connectors, use the theory of mode coupling to derive analytic formula of insertion loss and return loss under the action of end clearance, transverse off-set, end-face angle and damaged layer. Analyze the influence of optical fiber connectors' insertion loss and return loss on various factors based on practical parameters. We find that the pressure will ensure two fibers for physical contact, transverse off-set is the main factor affecting the insertion loss, and the main factor affecting the return loss are the thickness and refractive index of damaged layer in actual use.Secondly, put forward the improved method of insertion loss and return loss. Rotating pins to make the minimum angle between the eccentricity and positioning key can effectively reduce the transverse off-set to reduce the insertion loss for present ceramic pin making precision. Using appropriate concentration (5%) of hydrofluoric acid to etch optical fiber connectors can effectively reduce the thickness of damaged layer at the fiber end face, so as to improve the return loss of the optical fiber connector, UPC type can reach more than 60 dB. The smaller concentration of hydrofluoric acid is, the slower etching velocity become, and the larger concentration leads to fiber surface morphology and insertion loss affected badly.Finally, in order to ensure the physical contact of optical fiber after etched, we study the influence of grinding and polishing process to fiber height. We found that fiber height rapidly decreases at the beginning of polishing, due to the plastic flow of damaged layer, the thickness and refractive index decline obviously. But fiber height become stable as the polishing time increases because of the equilibrium state of damaged layer. Polishing pressure stabilize fiber height within a certain range. And grinding time have little impact on fiber height. Epoxy resin adhesive will slide at high temperature, which make fiber height reduce slightly according to the high temperature experiments after polished.