Taper microstructure optical fiber high-order mode filter

Abstract

The invention discloses a conical microstructure optical fiber high-order mode filter. The conical microstructure optical fiber high-order mode filter is characterized by consisting of a butt end with the same outside diameter at both ends and a waist cone part with the gradually reduced outside diameter at the middle; the length of the butt end with the same outside diameter at both ends is L1 and L5 respectively, wherein, the L1 equals 5-50cm, and the L5 equals 5-50cm; the outside diameter of the butt end is d1, and the d1 equals 25-1000mum; the length of a transitional part with the gradually reduced outside diameter is respectively L2 and L4, wherein, the L2 equals 0.1-10cm and the L4 equals 0.1-10cm; the butt end outside diameter d1of the transitional part with the gradually reduced outside diameter is transited to the thin end outside diameter d2, the cone gradient eta equals (d1-d2) / 2L which equals 0.001-1.0, wherein, the d1 is more than the d2; L is the L2 or the L4; the length L3 of the equal outside diameter part at the relatively thin middle part equals 0.1-10cm, and the outside diameter thereof d2 equals 10-200mum. The filter can effectively remove the high-order mode from an optical fiber transmission system with different visible and near infrared wavebands to realize the single mode transmission, the filter can be matched with multimode optical fiber with different outside diameters, and the fiber is characterized by easy coupling and small insertion loss.

Description

technical field [0001] The invention relates to an optical fiber mode filter, which can be coupled with an optical fiber transmission system and effectively filter high-order modes in visible and near-infrared bands. Background technique [0002] In the optical fiber transmission system, on the one hand, the relaxation of the fiber mode cut-off condition or the multimode transmission state can lead to the enhancement of other fiber characteristics, such as large mode area, low bending loss, and fiber dispersion characteristics of various performances. In general, the fundamental mode can be stably transmitted in a properly designed multimode fiber. However, when the optical power or optical signal is transmitted through multi-mode, it will cause inter-mode interference, which will seriously reduce the signal-to-noise ratio of the single-mode transmission system. On the other hand, if the single-mode condition is strictly pursued when designing the transmission fiber, it wil...

AI Technical Summary

Problems solved by technology

However, when the optical power or optical signal is transmitted through multi-mode, it will cause inter-mode interference, which will seriously reduce the signal-to-noise ratio of the single-mode transmission system.

On the other hand, if the single-mode condition is strictly pursued when designing the transmission fiber, it will limit or reduce the adaptability of the fiber in many practical applications

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