BEND-RESISTANT MINI OPTICAL FIBER AND MANUFACTURING METHOD THEREOF

Abstract

A bend-resistant mini optical fiber and manufacturing method thereof, first, preparing a preform via a modified chemical vapor deposition process, and manufacturing an optical fiber via drawing at a certain temperature. The advantageous of the present invention are as following, the bend-resistant mini optical fiber is primarily formed by a core layer, a platform layer, a depression layer, an outer cladding layer and a coating layer, and the relative refractive index and radius of each of the layers is reasonably controlled; and a cutoff wavelength is effectively controlled by employing an automatic temperature and tension monitoring procedure during the drawing process, such that the cutoff wavelength and a mode field diameter are maintained in a relatively stable range, and the cutoff wavelength is adjusted upward while the mode field diameter remains stable, thus facilitating a decrease of bend loss of the optical fiber.

Claims

1. A bend-resistant mini optical fiber, comprising a core layer, a platform layer, a depression layer, an outer cladding layer and a coating layer which are sequentially arranged from inside to outside; a refractive index of the core layer, a refractive index of the platform layer and a refractive index of the depression layer reduces sequentially; the relative refractive index of the core layer is 0.06 to 0.28% and a radius of the core layer is 2.5 to 3.5 um; the relative refractive index of the platform layer is 0.38 to 0.15%, a radius of the platform layer is 16 to 27 um; the relative refractive index of the depression layer is 0.7 to 0.15% and a radius of depression layer is 30 to 45 um; and the outer cladding layer is a pure silica glass layer with a diameter of 801 um.

2. The bend-resistant mini optical fiber according to claim 1, wherein when the diameter of the bend-resistant mini optical fiber is 10 mm and in case of winding the bend-resistant mini optical fiber around 100 turns or more, the bend loss of the bend-resistant mini optical fiber is less than 0.05 dB at 1550 nm.

3. The bend-resistant mini optical fiber according to claim 1, wherein a diameter of the coating layer is 155-170 um.

4. A manufacturing method of the bend-resistant mini optical fiber, the bend-resistant mini optical fiber comprises a core layer, a platform layer, a depression layer, an outer cladding layer and a coating layer which are sequentially arranged from inside to outside; a refractive index of the core layer, a refractive index of the platform layer and a refractive index of the depression layer reduces sequentially; the relative refractive index of the core layer is 0.06 to 0.28% and a radius of the core layer is 2.5 to 3.5 um; the relative refractive index of the platform layer is 0.38 to 0.15%, a radius of the platform layer is 16 to 27 m um; the relative refractive index of the depression layer is 0.7 to 0.15% and a radius of depression layer is 30 to 45 um; and the outer cladding layer is a pure silica glass layer with a diameter of 801 um; wherein the manufacturing method of the bend-resistant mini optical fiber comprises: (1) successively depositing the outer cladding layer, the depression layer, the platform layer and the core layer by a modified chemical vapor deposition method; (2) placing a deposited tube on a heat shrinking machine and fusing and shrinking the deposited tube into a solid preform; (3) fixing the preform on a drawing tower and drawn into an optical fiber at a temperature of 2150 C.; (4) installing a coating mold for drawing, cutting the optical fiber after drawing; (5) setting a curing distance of drawing tower as 2 m -4 m, and curing and drying the optical fiber in a curing oven; (6) after curing, winding the optical fiber on an automatic wire take-up device, designing the optical fiber drawing cone; wherein an angle of a V-shaped cone is controlled at 20 to 50 degrees to facilitate the positioning of the mini diameter optical fiber; (7) setting up a calculation model, and calculating the service life of the optical fiber according to elastic modulus of the optical fiber, force application time and bending coefficient.

5. The manufacturing method of the bend-resistant mini optical fiber according to claim 4, wherein a coating pressure at the drawing in the step (4) is 0.02 to 0.025 MPa and a drawing speed is 800 to 1500 m/min.

6. The manufacturing method of the bend-resistant mini optical fiber according to claim 4, wherein a total power of the curing oven in the step (5) is 18000-24000W.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] FIG. 1 is a distribution map of the refractive index profile structure of the bend-resistant mini optical fiber of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0027] As shown in FIG. 1, a bend-resistant mini optical fiber, includes a core layer, a platform layer, a depression layer, an outer cladding layer and a coating layer which are sequentially arranged from inside to outside; the refractive index of the core layer, the platform layer and the depression layer decreases sequentially; the relative refractive index of the core layer is 0.06 to 0.28% and the radius is 2.5 to 3.5 um; the relative refractive index of the platform layer is 0.38 to 0.15%, the radius is 16 to 27 um; the relative refractive index of the depression layer is 0.7 to 0.15% and the radius is 30 to 45 um; and the outer cladding layer is pure silica glass layer with diameter of 801 um.

Embodiment 1

[0028] The present invention further discloses a manufacturing method of a bend-resistant mini optical fiber, the manufacturing method is as follows:

[0029] (1) The outer cladding layer, the depression layer, the platform layer and the core layer are successively deposited by modified chemical vapor deposition method;

[0030] (2) The deposited tube is placed on heat shrinking machine and fused and shrank into solid preform;

[0031] (3) The preform is fixed on the drawing tower and drawn into optical fiber at a temperature of 2150 C.;

[0032] (4) Installing the coating mold for drawing, the coating pressure is controlled between 0.01-0.02 Mpa, the drawing speed is 500-800 m/min, cutting the optical fiber after drawing;

[0033] (5) Setting the curing distance of drawing tower as 2 m -4 m, and curing and drying the optical fiber in curing oven; the total power of the curing oven is 18000-24000W.

[0034] (6) After curing, the optical fiber is wound on an automatic wire take-up device, and the optical fiber drawing cone is designed. The angle of the V-shaped cone is controlled at 20 to 50 degrees to facilitate the positioning of the mini diameter optical fiber.

[0035] (7) Setting up the calculation model, and calculating the service life of the optical fiber according to the elastic modulus of the optical fiber, the force application time and the bending coefficient.

[0036] The table shown below is: Table of the relationship between coating pressure and drawing speed on the number of times of fiber breakages

Embodiment 2

[0037] A manufacturing method of a bend-resistant mini optical fiber is shown as below:

[0038] (1) The outer cladding layer, the depression layer, the platform layer and the core layer are successively deposited by modified chemical vapor deposition method;

[0039] (2) The deposited tube is placed on heat shrinking machine and fused and shrank into solid preform;

[0040] (3) The preform is fixed on the drawing tower and drawn into optical fiber at a temperature of 2150 C.;

[0041] (4) Installing the coating mold for drawing, wherein the coating pressure is controlled between 0.02-0.025 Mpa, the drawing speed is 800-1500 m/min, cutting the optical fiber after drawing;

[0042] (5) Setting the curing distance of drawing tower as 2 m -4 m, and curing and drying the optical fiber in curing oven; wherein the total power of the curing oven is 18000-24000W.

[0043] (6) After curing, the optical fiber is wound on an automatic wire take-up device, and the optical fiber drawing cone is designed. The angle of the V-shaped cone is controlled at 20 to 50 degrees to facilitate the positioning of the mini diameter optical fiber.

[0044] (7) Setting up the calculation model, and calculating the service life of the optical fiber according to the elastic modulus of the optical fiber, the force application time and the bending coefficient.

[0045] The table shown below is: Table of the relationship between coating pressure and drawing speed on the number of times of fiber breakages

Embodiment 3

[0046] A manufacturing method of a bend-resistant mini optical fiber is shown as below:

[0047] (1) The outer cladding layer, the depression layer, the platform layer and the core layer are successively deposited by modified chemical vapor deposition method;

[0048] (2) The deposited tube is placed on a heat shrinking machine and fused and shrank into solid preform;

[0049] (3) The preform is fixed on the drawing tower and drawn into optical fiber at a temperature of 2150 C.;

[0050] (4) Installing the coating mold for drawing, wherein the coating pressure is controlled between 0.025-0.035 Mpa, the drawing speed is 1500-2000m/min, cutting the optical fiber after drawing;

[0051] (5) Setting the curing distance of drawing tower as 2 m -4 m, and curing and drying the optical fiber in curing oven; wherein the total power of the curing oven is 18000-24000W.

[0052] (6) After curing, the optical fiber is wound on an automatic wire take-up device, and the optical fiber drawing cone is designed. The angle of the V-shaped cone is controlled at 20 to 50 degrees to facilitate the positioning of the mini diameter optical fiber.

[0053] (7) Setting up the calculation model, and calculating the service life of the optical fiber according to the elastic modulus of the optical fiber, the force application time and the bending coefficient.

[0054] The table shown below is: Table of the relationship between coating pressure and drawing speed on the number of times of fiber breakages

[0055] According to the above embodiments, the optical fiber in Embodiment 2 has the least number of breakages in the drawing process, and at this time, the structure is the most stable and has the best quality. Therefore, the coating pressure of 0.02 to 0.025 MPa and the drawing speed of 800 to 1500 m/min are selected.

[0056] The basic principles and main features of the present invention have been shown and described above. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments, and the above embodiments and description only illustrate the principle of the present invention.

[0057] Without departing from the spirit and scope of the present invention, the present invention also has various changes and modifications which fall within the scope of the claimed invention. The scope of protection demanded by the present invention is defined by the appended claims and their equivalents.