Double waveguide parallel polarization maintaining fiber and manufacturing method thereof

Abstract

The invention relates to a double waveguide parallel polarization maintaining fiber and a manufacturing method thereof. The double waveguide parallel polarization maintaining fiber comprises two polarization maintaining fibers with the same waveguide structure, and is characterized in that: symmetrical sides of the two polarization maintaining fibers are connected in parallel or connected in parallel into a whole, and the stress zone directions of fiber waveguide of the two polarization maintaining fibers are consistent with the parallel direction or are vertical to the parallel direction; coatings are wrapped outside the two polarization maintaining fibers; and the sections of the coatings have a smooth pancake shape. Two polarization maintaining fiber prefabrication rods are arranged in a fiber drawing furnace in parallel or two fiber drawing furnaces which are arranged in parallel; and the two polarization maintaining fiber prefabrication rods are heated simultaneously, melted in a high temperature and drawn to form fibers. The manufacturing accuracy of a fiber loop used in the field of fiber optic gyros and fiber optical sensors, and the stress and temperature sensitivity of the fiber loop are improved, and the improvement on the process for manufacturing the fiber loop is facilitated.

Description

technical field [0001] The invention relates to a dual-waveguide parallel polarization-maintaining optical fiber and a manufacturing method thereof, belonging to the technical fields of optical fiber gyroscope and optical fiber sensing. Background technique [0002] Polarization maintaining fiber is a kind of special fiber. Polarization maintaining fiber, that is, linear polarization maintaining fiber, is a type of fiber that maintains the linear polarization direction of the transmitted light. Polarization-maintaining fiber can be used in many fields, such as multiplexing coherent communication, fiber optic gyroscope, fiber optic hydrophone, fiber optic sensing, etc. Polarization maintaining fiber is a special fiber type with wide application value. [0003] In ordinary communication optical fiber, due to its circular symmetry structure, after a certain distance of transmission, the incident linearly polarized light will become circular or elliptical polarized light due t...

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Problems solved by technology

[0005] Using the existing circular cross-section polarization maintaining optical fiber products, there are the following problems in the winding process of the optical fiber ring: firstly, due to the circular structure, the upper layer of optical fiber will inevitably wind along the V-shaped groove formed by the lower layer of optical fiber, such as Figure 4 As shown, the upper-layer optical fiber cannot be located above the lower-layer optical fiber according to the requirements of the quadrupole winding method; secondly, because the upper-layer optical fiber is wound along the V-shaped groove formed by the lower-layer optical fiber, when the optical fiber goes from one circle of V-shaped groove to the adjacent one When the V-shaped groove jumps forward, there will be a cross-lap point between the upper and lower layers of fibers. The existence of this cross point will have a significant impact on the performance of the fiber ring. How to deal with the cross point that occurs during the ring is the fiber ring The technical difficulties of winding; third, due to the use of circular cross-section optical fibers, it is difficult to ensure that the circular cross-section optical fibers do not twist during the winding process of the optical fiber ring, and this optical fiber twist will affect the optical fiber ring due to the geomagnetic Faraday effect. The accuracy of the loop will have a negative impact; Fourth, because the fiber loop winding is very strict on the control of the fiber length, fiber position and tension, the longer the fiber that needs to be wound, the more difficult it is to guarantee the winding quality of the fiber loop

However, this method adds a lot of optical fiber fusion joints in the process of coil winding, which will lead to unstable performance of the sensing coil

At the same time, using this method to wind the optical fiber ring, the introduction of optical fiber and other polymer materials such as glue, has a negative impact on the temperature stability of the optical fiber ring

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