Large-core-diameter bend insensitive energy transmitting optical fiber

Abstract

The invention relates to a large-core-diameter bend insensitive energy transmitting optical fiber. The large-core-diameter bend insensitive energy transmitting optical fiber comprises a core layer and cladding layers and is characterized in that the core layer is distributed according to a gradually-changing refractive index, the distribution power exponent alpha ranges from 1.8 to 2.1, the maximum value delta1%max of the relative refraction index difference of the core layer ranges from 1.0% to 2.5%, the radius R1 of the core layer ranges from 95 micrometers to 500 micrometers, the inner cladding layer and the outer cladding layer are sequentially arranged on the core layer from inside to outside, the relative refraction index difference delta2% of the inner cladding layer ranges from -0.6% to -1.3%, the specific value of the radius of the inner cladding layer to the radius of the core layer satisfies the equation that w1=R2 / R1 and ranges from 1.05 to 1.2, the outer cladding layer is a pure quartz glass layer, and the specific value of the radius of the outer cladding layer to the radius of the core layer satisfies the equation that w2=R3 / R1 and ranges from 1.1 to 1.4. According to the large-core-diameter bend insensitive energy transmitting optical fiber, the light receiving capacity and the light condensation capacity of the optical fiber can be remarkably improved, the optical fiber has good transmission efficiency and can bear high-energy laser transmission, the design of the profile with the gradually-change refractive index is adopted for the core layer, and therefore the optical fiber has the self-focusing effect and has more advantages in practical application such as laser processing.

Description

technical field [0001] The invention relates to a bending-insensitive energy-transfer optical fiber with a large core diameter. The optical fiber can carry high-energy laser transmission, has good bending insensitivity and excellent transmission efficiency, and belongs to the technical field of optical fiber energy transmission. Background technique [0002] The large core diameter multimode energy transmission fiber can flexibly and safely transmit high laser energy in a three-dimensional complex space, and can transmit high-power laser to a specific position, simplifying the optical path system and improving the flexibility of the laser system application work platform Function, has been widely used in military, laser processing, medical, sensing, lighting and many other fields. [0003] In the prior art, conventional large-core energy-transmitting optical fibers are mainly divided into two structures, one is a step-type refractive index profile structure, and the other is...

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Problems solved by technology

For example, the Chinese patent CN102721998A adopts this method. This kind of energy-transmitting optical fiber can provide convenient and efficient coupling operation, but the disadvantage is that the cost of low-refractive index coating is relatively high, and under the same environmental conditions, when transmitting higher energy, the coating It is easy to generate heat, which will cause the softening or even burning of the low-refractive index coating, resulting in the failure of the fiber, and the bending insensitivity of the fiber with this structure is also poor

[0005] In addition, when the light is transmitted in the optical fiber, its beam quality factor M 2 The core diameter of the fiber changes exponentially, and after being transmitted through a fiber with a certain core diameter and numerical aperture, the beam quality factor M 2 The maximum value is related to the core diameter and numerical aperture angle of the fiber. When we use it, the fiber will inevitably be bent to varying degrees. When the fiber is subjected to large bending stress for a long time, the service life of the fiber will inevitably be shortened, and the transmission performance index It will also decrease. For this reason, the optical fiber is required to have certain bending characteristics to meet the needs of different occasions.

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