| 摘要 |
Signal strength in an optical fiber transmission path is attenuated in one direction to a desired lower level by incorporating a selected length of coreless, undoped fiber of the same diameter into the signal-carrying fiber. On encountering the insert, the beam diameter expands to a pre-selected value at the far end of the insert. The ratio of the beam diameter at this point to the diameter of the adjacent fiber end establishes the attenuation factor. Steps are taught for achieving high consistency in both structural strength of the attenuator as well as the attenuation factor.
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