Analysis of Splice Loss of Single-Mode Optical Fiber in the High Altitude Environment

Up to now, there have been no complete theoretical researches and field experiment reports on the fiber fusion loss at high altitude. Therefore, we have conducted an exploratory study on the fiber splicing loss at high altitude, and firstly analyze the influence of mode field diameter mismatch, axial offset, angle tilt or end face gap affected by high altitude on splice loss, and then discuss the influence of fusion-splicing parameters on splice loss. Besides, a mathematical model for reducing the splicing loss of single-mode fiber at high altitude is established by combining the effects of temperature, humidity, oxygen content, atmospheric pressure, gale and gravity. We have conducted repeated field fusion experiments in different altitude areas (53, 2980, 4000, 4200, 4300, 5020, and 5200 m) more than once, hence obtaining a large number of field experimental data, making a deep comparison between typical “plain” area and typical “high altitude” area. The splice loss of most fusion points achieved successfully has been reduced by at least 0.07 dB. The simulation results are basically consistent with the theoretical analysis. Ultimately, the method proposed has been directly applied to on-site splicing engineering in high altitude environment and achieves good results.

Micrometer Scale Resolution Limit of a Fiber-Coupled Electro-Optic Probe

We present the practical resolution limit of a fine electrical structure based on a fiber-coupled electro-optic probing system. The spatial resolution limit was experimentally evaluated on the sub-millimeter to micrometer scale of planar electrical transmission lines. The electrical lines were fabricated to have various potential differences depending on the dimensions and geometry. The electric field between the lines was measured through an electro-optic probe, which was miniaturized up to the optical bare fiber scale so as to investigate the spatial limit of electrical signals with minimal invasiveness. The experimental results show that the technical resolution limitation of a fiber-coupled probe can reasonably approach a fraction of the mode field diameter (~10 μm) of the fiber in use.