Mode-field diameter measurements for single-mode fibers with non-Gaussian field profiles

In metro and long haul networking applications, Erbium Doped Fiber Amplifiers (EDFAs) are used to amplify weak optical signals. Manufacturing of EDFAs is primarily a fusion splicing process in which both Single Mode Fibers (SMFs) and Erbium Doped Fibers (EDFs) are utilized. One of the critical operations is the splicing of an SMF to an EDF, a dissimilar fiber splicing process. Splice losses between these fibers need to be optimized, and the process is highly reliant on the properties of the EDF. Mode Field Diameter (MFD), spectral attenuation at peak wavelength and concentration of erbium along its length vary from batch to batch. The splice loss is dependent on some of these properties and must be taken into consideration. With this background, research was conducted to study the properties of EDFs and its applicability in the splicing process. Having considered the characteristics of the EDF in different wavelength regions, experiments were designed to optimize the losses between an SMF and an EDF. In the C-band (1525–1565 nm), erbium atoms absorb most of the transmitted power (in absence of a 980/1480 nm laser pump). Splice losses measured in these regions are dependent upon the absorption properties and would not depict a true picture of the splice loss. Since the incident power is absorbed, an alternate approach would be to launch extremely low power (<−27 dBm). In this case, the absorption losses should be minimal. As C-band is highly absorptive, launching power in the range of 1310 nm would be another possible scenario. The ‘cutback’ method was also employed to determine the losses in the C-band region. Statistical methods such as the Design of Experiments (DOE) were used to study the properties of the EDF and its response to various splicing parameters and wavelengths. Splice loss trends at various power levels were also investigated. The primary intent of these experiments was to translate the results and their utility into the manufacturing of EDFAs, wherein a multitude factors creep into the splicing scenario. The best method would be the one that consistently yields a low splice loss, since these are critical to minimize the noise figure of the EDFA.

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

Coatings ◽

10.3390/coatings11080876 ◽

2021 ◽

Vol 11 (8) ◽

pp. 876

Author(s):

Liwen Hu ◽

Chaowei Yuan

Keyword(s):

High Altitude ◽

Atmospheric Pressure ◽

Single Mode ◽

Single Mode Fiber ◽

Plain Area ◽

Splice Loss ◽

Mode Field ◽

Mode Field Diameter ◽

High Altitude Area ◽

Effects Of Temperature

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.

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