Optical fibre fused tapering method using high-frequency pulse carbon dioxide laser as heat source

Abstract

The invention relates to an optical fibre fused tapering method using high-frequency pulse carbon dioxide laser as a heat source. The method precisely adjusts laser beams based on the good heat absorption performance of a silica optical fibre close to the carbon dioxide laser wavelength and the characteristics that the high-frequency carbon dioxide laser can generate a continuous high temperature, so that a fused tapered optical fibre is drawn while the laser beams heat up the optical fibre continuously along a certain optical fibre length. The method is mainly characterized by: designing a reasonable laser beam scanning track graph, and ensuring that the laser beams scan the optical fibre all the time during the whole drawing procedure and that a heat area stable enough can be generated on the optical fibre; and simultaneously adjusting the parameters of the carbon dioxide laser beams and the step length of a stepping motor, so as to ensure the heat and force balance of the optical fibre during the drawing procedure. The method does not pollute the optical fibre, and is not influenced by the indoor airflow, oxygen content and the like; and the heat source is similar to a point heat source, and the manufacture precision of the fused tapered optical fibre is greatly improved. The fused tapered optical fibre manufactured by the method can be widely used in the fields like beam splitting and connection of light, optical fibre sensing, optical filters, optical communications and the like; and the application potential is huge.

Description

technical field [0001] The invention relates to an optical fiber fusion tapering method using a high-frequency pulsed carbon dioxide laser as a heat source, and belongs to the technical field of optical fibers. Background technique [0002] carbon dioxide (CO 2 ) Laser processing technology has been successfully applied in the preparation of many micro-optical devices based on fiber processing. For example, the production of long-period fiber gratings, near-field scanning probes and fused tapered fibers. Fused tapered fiber is a special waveguide structure with tapered waist and symmetrical biconical transition region, which is widely used in many optical devices, such as fused fiber directional couplers, tunable filters and fiber optic evanescent wave sensors. [0003] Fused tapered optical fiber is generally made of optical fiber through fusion tapered technology. It uses a heat source to heat a section of optical fiber that has been removed from the protective layer to...

AI Technical Summary

Problems solved by technology

By consulting the literature, it can be found that: Existing CO 2 In the laser as a heat source fusion tapering method, the equipment is more complicated; The diameter of the laser spot used reaches hundreds of microns (or larger). If you want to reach the melting point of the optical fiber (about 1800 degrees Celsius), you need to use a high-power (20 watts or larger) laser, which leads to relatively high energy consumption; Most of the selected lasers are continuous light, which is not conducive to overcome the hysteresis of the galvanometer (in the actual scanning process, the galvanometer has a certain hysteresis, that is, when the galvanometer moves to the left and right ends of the scanning area, the galvanometer The acceleration disappears instantaneously, and the laser beam does not stop at this time, which leads to the formation of a laser-intensive area at the edge of the hot zone, resulting in excessive temperature, and even physical damage to the optical fiber), which is not conducive to producing a relatively stable Hot zone range

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