TWI442114B - A fabrication method of few-mode double-clad crystal fibers and a processing method of double-clad crystal fibers - Google Patents

Description

Method for manufacturing near single mode double fiber clothing crystal fiber and processing method of double fiber clothing crystal fiber

The present invention relates to a method for fabricating an optical fiber, and more particularly to a method for forming a near-monomodal double-fiber crystal fiber by adjusting the core diameter of the double-fiber crystal fiber.

Conventional fiber manufacturing methods (for example, wire drawing tower technology or laser pedestal heating growth method (LHPG), etc.) are used to coat a fiber (Cladding) on a core to form an optical fiber. (Optical Fibers), wherein the "spinning tower technology" is used to form the core and the fiber by an amorphous germanium material having different refractive indices, but the material of the core is amorphous, rather than having good optics. , yttrium aluminum garnet (YAG) crystals with thermal and mechanical properties. The "laser radiant heating growth method" (LHPG) is used to form the yttrium aluminum garnet crystal into the core of a crystal fiber (Crystal Fibers, or crystal fiber), and the core can be doped with nickel ions (Ni ^a transition material such as ²⁺ ) and chromium ion (Cr ⁴⁺ ), such that the crystal fiber has a broad-band emission spectrum of 1.3 to 1.6 micrometers (μm), but the diameter of the core is difficult to be reduced to less than 10 micrometers, and The diameter of the core varies with length, resulting in increased insertion loss (Insertion Loss). In order to overcome the above problems, an improved method based on the laser pedestal heating growth method has been developed.

Please refer to FIG. 1 , for example, the invention patent of "Indirect Heating Double Fiber Crystal Optical Fiber Manufacturing Method" of the Republic of China Announcement No. I318305, discloses a conventional method for manufacturing a double fiber clothing crystal fiber, which is prepared by a crystal fiber. Procedure to make a Double-Clad Crystal Fibers 9. In detail, the crystal fiber preparation process first prepares a crystal fiber 91, and inserts the crystal fiber 91 into a glass capillary (Fused Silica Capillary Tube) 92, and then sets a periphery of the melting zone where the glass capillary 92 is to be heated. The tubular crystal 93 is further heated by irradiating the tubular crystal 93 with a laser R to gradually raise the temperature of the tubular crystal 93, and heat radiation is generated to heat the glass capillary 92, so that the glass capillary 92 is coated with high temperature. The crystal fiber 91 further forms a Fused-Silica coated double-fiber crystal fiber 9. Wherein, when the tubular crystal 93 is gradually raised in temperature to reach a diffusion and fusion temperature (for example, 1600 ° C), the heat radiation generated by the tubular crystal 93 causes the crystal fiber 91 and the glass capillary 92 to start to be generated. The phenomenon of mutual diffusion, that is, the crystal fiber 91 and the glass capillary 92 begin a "collapsing process", and after a period of time, the power of the laser R is lowered, so that the temperature of the tubular crystal 93 is lower than the Diffusion and fusion temperature, the inter-diffusion phenomenon is stopped between the crystal optical fiber 91 and the glass capillary 92, that is, the crystal optical fiber 91 and the glass capillary 92 complete the "diffusion and integration process", and the double-fiber crystal fiber is completed. The manufacturing process of 9 (i.e., the crystal fiber preparation procedure), and the fiber diameter of the double-fiber crystal fiber 9 is less than 10 μm and the core diameter is uniform.

Please refer to FIG. 2, which is a graph of the core diameter change of the conventional method for manufacturing a double-fiber crystal fiber, wherein when the "diffusion and integration process" starts (ie, the time value ≧0), As the laser intensity increases, the core size (ie, the core diameter) tends to decrease; otherwise, the core size tends to increase. Therefore, for a long time, if a double-fiber crystal fiber 9 having a small core diameter is to be produced, the laser intensity must be increased in the crystal fiber preparation process, so that the fiber can be formed after the crystal fiber preparation process is completed. Double-fiber crystal fiber 9 with a small heart diameter.

In addition, since the energy output distribution of the near-mode optical fiber (Few-Mode Fibers) is close to that of the single-mode fiber, it has the advantages of improving the "gain ion absorption pump source power" and lowering the "laser threshold power". Near-single-mode fiber has a core diameter of 微米2 μm. If a conventional double-fiber crystal fiber manufacturing method is used to manufacture "near-mode uni-fiber double-fiber crystal fiber", it is necessary to add a thunder to the "diffusion and integration process". The intensity of the shot is used to reduce the core diameter of the double-fiber crystal fiber 9. However, the conventional method for manufacturing a double-fiber crystal fiber can only reduce the diameter of the core to 5±0.25 μm (please refer to page 8 of the specification of the Republic of China Announcement No. I318305), and if the laser intensity is further increased, However, because the heating temperature is too high, the viscosity of the glass material is lowered, and the core discontinuity or the core diameter is not uniform. Therefore, the conventional double-fiber crystal fiber manufacturing method cannot manufacture the near-single mode. State double fiber clothing crystal fiber."

In addition, there is no other literature mentioning the manufacturing method of the near-monomodal double-fiber crystal fiber or the processing method of the double-fiber crystal fiber to reduce the core diameter of the double-fiber crystal fiber to the near single The core diameter of the modal fiber. Therefore, for a long time, there is a problem in the industry that it is impossible to manufacture near-single-mode double-fiber crystal fiber. When the optical signal of the communication optical band is transmitted in the double-fiber crystal fiber, the energy output distribution cannot be close to the single-mode fiber, and therefore, not only The "gain ion absorption pump source power" cannot be increased, and the "laser threshold power" cannot be lowered.

In summary, it is necessary to provide a method for manufacturing a near-monomodal double-fiber crystal fiber to produce a fiber core diameter reduced to a near-monomodal fiber core diameter, a uniform core diameter, and a core material of bismuth aluminum. A double-fiber crystal fiber of garnet crystals, and a method for processing a double-fiber crystal fiber to reduce the core diameter of the double-fiber crystal fiber 9 to the core diameter of the near-mono-mode fiber.

The object of the present invention is to improve the above disadvantages, and to provide a method for manufacturing a near-monomodal double-fiber crystal fiber, which is manufactured by repeatedly adjusting the diameter of the core to reduce the core diameter to the near-simular fiber. The core diameter, the core diameter are uniform, and the core material is a near-unimodal double-fiber crystal fiber of yttrium aluminum garnet crystal.

A second object of the present invention is to provide a method for processing a double-fiber crystal fiber, wherein the core diameter of the double-fiber crystal fiber can be reduced to a near single mode by performing at least one core adjustment procedure on the double-fiber crystal fiber. The core diameter of the fiber is formed to form a near-unimodal double-fiber crystal fiber.

A method for manufacturing a near-single-mode double-fiber crystal fiber comprises: a crystal fiber preparation process for performing a diffusion and mutual fusion process to prepare a double-fiber crystal fiber; and a core adjustment program The double-fiber crystal fiber re-does the diffusion and fusion process at least once until the core diameter value of the double-fiber crystal fiber is reduced to a near-unimodal core diameter value to form a near-monomodal double-fiber crystal Fiber; wherein the laser power value of each of the diffusion and mutual fusion processes is successively decreased.

The laser power value of the diffusion adjustment process is lower than the laser power value of the diffusion process.

Wherein, if the number of times of the diffusion and integration process of the core adjustment procedure is repeated several times, the laser power value of each of the diffusion and integration processes is successively decreased.

Wherein, the crystal fiber preparation process is irradiated to a tubular crystal by a laser to generate heat radiation, so that a crystal fiber and a glass capillary tube start the diffusion and mutual fusion process, and the double fiber is formed after the diffusion and integration process is completed. Clothing crystal fiber.

Wherein, the core adjustment program comprises: an adjusting step, wherein the diffusion and mutual fusion process is started again by the double-fiber crystal fiber, and the core diameter of the double-fiber crystal fiber is reduced, wherein the adjusting step is The laser power value of the diffusion and integration process is lower than the laser power value of the previous diffusion and integration process; and a judging step is to determine whether the core diameter value of the fiberglass fiber is reduced to the near single mode If the value is determined to be YES, the diffusion and mutual fusion process is terminated to form the near-monomodal double-fiber crystal fiber. If the determination is negative, the diffusion and mutual fusion process is to be completed. Perform this adjustment step.

A method for processing a double-fiber crystal fiber comprises: an adjusting step of performing a diffusion and mutual fusion process by a pair of fiber-optic crystal fibers, thereby reducing a core diameter of the fiber-optic fiber, wherein the adjusting The laser power value of the step is lower than the laser power value of the diffusion and fusion process during the manufacturing of the double fiber crystal fiber, and if the adjustment step is not performed for the first time, the laser power value of the diffusion and integration process is lower than a laser power value of the last diffusion process; and a determining step of determining whether the core diameter value of the fiberglass fiber is reduced to a predetermined diameter value, and if the determination is yes, ending the diffusion The mutual fusion process is performed to form a near-monomodal double-fiber crystal fiber. If the determination is negative, the adjustment step is performed after the diffusion and mutual integration process is completed.

Wherein the predetermined diameter value is equal to a near single mode core diameter value.

Wherein the predetermined diameter value is greater than a near single mode core diameter value.

Wherein, the core material of the double-fiber crystal fiber is yttrium aluminum garnet crystal.

The above and other objects, features and advantages of the present invention will become more <RTIgt;"CrystalFibers" refers to a crystalline fiber whose core material is a crystal, such as yttrium aluminum garnet crystal. The space group of garnet belongs to Ia-3d (O _h ¹⁰ ). The formula can be written as Y3Al5Ol2 (YAG), which is understood by those of ordinary skill in the art to which the present invention pertains.

"Double-Clad" as used throughout the present invention refers to a crystal fiber which is mainly composed of a core material which mainly transmits light energy, and is coated with two layers of glass as a main material, which has the technical field of the present invention. Usually the knowledge person can understand.

"Cr-Doped" as used throughout the present invention refers to the incorporation of chromium ions into a YAG material, as will be understood by those of ordinary skill in the art to which the present invention pertains.

The "Few-Mode" as described in the full text of the present invention means that when the optical signal of the communication optical band is transmitted in the optical fiber, the energy output distribution is close to the optical fiber state of the single-mode optical fiber, wherein when the optical fiber structure is As the core diameter becomes smaller, the higher order mode is cut off with the reduced core diameter, and the number of modes that can exist in the fiber is less and less, once the core diameter size is less than a certain value. All high-order modes will be cut off, and only the lowest-order basic modes exist. Taking the single-mode 矽 fiber SMF28 produced by Corning as an example, the incident light wavelength is calculated by 1.55 micrometer, and the core refractive index n1=1.465, the fiber refractive index n2=1.46, and the core radius is less than 9 micrometers, all The higher order modes will all be cut off. This concept can be simply calculated using V-number, given the fiber structure size and refractive index and the wavelength of the incident light. If V≦2.405, then the fiber has only the lowest order fundamental mode. The V-number of the present invention is 3.8 at 1.4 micrometers, which is quite close to the theoretical value (V=2.405), so it is called near-unimodal (Few-Mode), which can be understood by those having ordinary knowledge in the technical field to which the present invention pertains. .

The "Lray Base Heating Growth Method" (LHPG), or LHPG growth method, of the present invention belongs to the floating melting zone method, which was first developed by Burrus and Stone, and the LHPG growth method is a continuous CO2 mine. As a heating source, the CO2 laser light source attenuates the power through the attenuator, and the laser beam is expanded by two convex lenses, so that the original laser beam with a diameter of 5 mm is amplified to 3 cm, and then enters the growth chamber. When a 3 cm CO2 laser enters the growth chamber, it passes through a set of mirrors inside and outside the cone. At this time, the circular beam is converted into a ring beam, and then the laser is irradiated through a plane mirror with an inclination of 45°. Reflecting the parabolic mirror into the top, the parabolic mirror focuses the CO2 laser light on the top of the original ingot to fuse the top of the original ingot. By properly controlling the power of the CO2 laser, the top of the original ingot is formed. The molten hemisphere is controlled by the computer interface to slowly move the subcrystals into contact with the melting zone, then adjust the shape of the melting zone so that the upper and lower fixed interfaces are horizontal, and then slowly pull the subcrystals upwards, with power attenuation. Fine-tune the power of the CO2 laser to adjust the size of the melt zone so that the height of the melt zone is close to the diameter of the original ingot. At this time, the seed crystal is pulled up and the original crystal bar is pushed up to grow the crystal. Optical fibers are understood by those of ordinary skill in the art to which the present invention pertains.

The "collapsing process" in the present invention refers to a tubular sapphire crystal when a tubular sapphire crystal is heated to be greater than or equal to a diffusion and fusion temperature (for example, 1600 ° C). Producing heat radiation, such that the temperature between the crystal fiber forming the double-fiber crystal fiber and the glass capillary increases the glass softening temperature, and begins to generate an interdiffusion phenomenon (ie, begins the diffusion and mutual fusion process) until the tubular crystal When the temperature is less than the diffusion and fusion temperature, the temperature between the crystal fiber and the glass capillary is lowered, and the occurrence of the interdiffusion phenomenon (i.e., stopping the diffusion and mutual fusion process) is stopped, which is understood by those skilled in the art to which the present invention pertains.

The "Gain Medium Absorbed Pumping Power" in the present invention refers to when a transition metal material such as nickel ions (Ni ²⁺ ) and chromium ions (Cr ⁴⁺ ) is doped into the core. The ions in the transition metal material absorb the energy of the laser excitation source, as will be understood by those of ordinary skill in the art to which the present invention pertains.

The "Pumping Threshold Power" in the present invention means that when the laser pump power increases by a critical value, the number of particles of the laser gain medium is reversed, and The stimulated radiation is greater than the spontaneous radiation to produce a laser output, and the critical value at this time is referred to as the laser threshold power, as will be understood by those of ordinary skill in the art to which the present invention pertains.

The "a diameter value of the core of the few-mode double-clad crystal fiber" refers to a core fiber refractive index n1=1.82 and an inner layer. When the refractive index of the fiber is n2=1.64, the high-order mode is cut off when the core radius needs to be 2 μm. Therefore, the core diameter value of the near-monomorphic crystal fiber is 微米2 μm, which is the technology of the present invention. Those with ordinary knowledge in the field can understand.

Please refer to FIG. 3 , which is a schematic diagram of a system for manufacturing a near-single-mode double-fiber crystal fiber according to a preferred embodiment of the present invention, which is manufactured by a crystal fiber manufacturing device A to produce a double fiber crystal fiber. 1 (for example, a core diameter value of ≧ 5 μm), and then reducing the core diameter value of the double-fiber crystal fiber 1 to a predetermined diameter value (for example, a near-monomodal core diameter value) to form a Near monomodal double fiber clothing crystal fiber 2. In this embodiment, the crystal fiber manufacturing device A is a conventional laser pedestal heating growth (LHPG) device, which is not limited thereto; the crystal fiber manufacturing device A includes a laser R and a tubular crystal T The laser R can be irradiated to the tubular crystal T for heating, wherein the crystal fiber manufacturing apparatus A can also execute a manufacturing program and/or display an instant image of the double-fiber crystal fiber 1 for observing and adjusting the double The core diameter of the fiber-optic crystal fiber 1; the double-fiber crystal fiber 1 is a conventional double-fiber crystal fiber, for example, Cr-Doped Double-Clad Crystal Fibers, etc., but This is limited.

Referring to FIG. 4, which is a flow chart of a preferred embodiment of a method for manufacturing a near-simular dual-fiber crystal fiber of the present invention, the method for manufacturing a near-simular double-fiber crystal fiber of the present invention comprises a crystal fiber preparation program S1 and a core adjustment program S2, the crystal fiber preparation program S1 is subjected to a diffusion process (Collapsing Process) once to prepare the double fiber clothing crystal fiber 1, and then the core fiber is further processed. Adjust program S2. In detail, the crystal fiber preparation program S1 is a conventional method for manufacturing a double-fiber crystal fiber, and the laser light is irradiated onto the tubular crystal T to generate heat radiation, so that a crystal fiber 11 and a glass are produced. The capillary (Fused Silica Capillary Tube) 12 begins a diffusion and mutual fusion process, and the double-fiber crystal fiber 1 is formed after the diffusion and fusion process is completed, and is not described herein. The core diameter value of the double-fiber crystal fiber 1 is greater than the near-unimodal core diameter value; the laser power value of the laser R may be a constant value or a variable value (for example, power and time) Relationship curve, etc.).

The core adjustment procedure S2 is to perform the diffusion and mutual fusion process at least once until the core diameter value of the double-fiber crystal fiber 1 is reduced to the predetermined diameter value, wherein, if the predetermined The diameter value is the near-monomodal core diameter value, and the near-monomodal double-fiber crystal fiber 2 can be formed. The laser power value of the diffusion adjustment process is lower than the laser power value of the diffusion preparation process, and the diffusion adjustment of the core adjustment program S2 is performed. If the number of times the process is re-executed is several times, the laser power values of the diffusion and mutual integration processes are successively decreased, in other words, the laser power of the diffusion process of the crystal fiber preparation program S1 and the core adjustment program S2 The value is gradually reduced. In this embodiment, the near-unimodal core diameter value is described by using 2 micrometers as an implementation example, but not limited thereto.

In detail, the core adjustment program S2 includes an adjustment step S21 and a determination step S22. The adjustment step S21 is performed again by the double-fiber crystal fiber 1 to perform the diffusion and mutual fusion process to make the double-fiber crystal The core diameter of the fiber 1 is reduced, wherein the laser power value of the adjusting step S21 is lower than the laser power value of the diffusion and fusion process during the manufacturing of the fiber-optic fiber, and the adjusting step S21 is not performed for the first time. The laser power value of the diffusion and integration process is lower than the laser power value of the previous diffusion and integration process. Thereafter, the determining step S22 is performed again. More specifically, the adjusting step S21 penetrates the double-fiber crystal fiber 1 into the tubular crystal T, and the tubular crystal T is heated by the laser R, and the tubular crystal T generates heat radiation to heat the double-fiber crystal. Fiber 1 causes the double-fiber crystal fiber 1 to start the diffusion and mutual fusion process again, wherein by reducing the laser power value, the ion diffusion effect (Ions Diffusion) of the double-fiber crystal fiber 1 can be weakened and slowed down. The degree of inter-diffusion between the crystal optical fiber 11 and the glass capillary tube 12 reduces the core diameter of the double-fiber crystal fiber 1, thereby increasing the adjustability of the core diameter value of the double-fiber crystal fiber 1. Thereafter, the determining step S22 is performed again. The power control technology can perform the feedback calculation on the laser power value to maintain the variation of the laser power value at ±0.1%.

The determining step S22 is to determine whether the core diameter value of the double-fiber crystal fiber 1 is reduced to the predetermined diameter value, for example, the near-unimodal core diameter value, but not limited thereto. Then, the diffusion and mutual fusion process is completed to form the near-unimodal double-fiber crystal fiber 2; if the determination is "NO", the adjustment step S21 is performed after the diffusion and mutual integration process is completed. More specifically, the determining step S22 is performed by the instant image monitoring technology, for example, by forming a video with a charge coupled device (CCD) and a computer program, and the crystal fiber manufacturing device A or a display device (not shown) Observing the real-time image of the double-fiber crystal 1 and monitoring the core diameter value of the double-fiber crystal 1 by a user or a manufacturing program to determine whether the diffusion is completed at the end After the melting process, the adjustment step S21 is performed again. Wherein, if the core diameter value has not been reduced to the predetermined diameter value, the diffusion and mutual fusion process may be ended first when the core diameter of the double-fiber crystal fiber 1 is kept uniform, so that the double-fiber crystal fiber 1 can be cooled and solidified while maintaining the core diameter uniformly, so as to perform the adjusting step S21 again to slightly trim the core diameter of the double-fiber crystal fiber 1; conversely, if the core diameter value has been reduced to the predetermined diameter value (for example, the near-monomodal core diameter value), the diffusion and mutual fusion process is directly ended, and the near-monomodal double-fiber crystal fiber 2 is formed. In this embodiment, the diffusion and mutual fusion process is performed three times, and the predetermined diameter value is set to 2 micrometers as an embodiment, but is not limited thereto.

For example, the crystal fiber preparation program S1 is prepared by preparing the crystal optical fiber 11, for example, a chrome-doped yttrium aluminum garnet (Cr:YAG) ingot having a diameter value and a length value of 0.5 mm (mm) and 3, respectively. Dimensions (cm); after the crystal fiber 11 is subjected to the LHPG Method twice, the diameter of the crystal fiber 11 is reduced to 70 ± 2 μm; then, the crystal fiber 11 is placed in the glass. The capillary 12, for example, a glass capillary 12 having an inner diameter of 76 μm and an outer diameter of 320 μm; thereafter, the crystal optical fiber 11 and the glass capillary 12 are penetrated at a crossing speed (for example, 3 to 5 mm/min). a tubular crystal T (for example, a sapphire transistor or the like), and simultaneously irradiated to the tubular crystal T by the laser R (for example, a CO ₂ laser or the like) for heating, wherein a power curve of the laser R is the first power Curve P1 (as shown in Fig. 5) causes the tubular crystal T to gradually increase in temperature, and heat radiation is generated to heat the glass capillary tube 12. The crystal optical fiber 11 and the glass capillary tube 12 are subjected to the diffusion and mutual fusion process. Interacting between the crystal fiber 11 and the glass capillary 12 (interdif) a fusion phenomenon, after the diffusion and mutual fusion process is completed, an inner cladding layer is formed, so that the crystal optical fiber 11 and the glass capillary 12 together form a double-coated crystal fiber 1 which is melt-coated. .

The core adjustment program S2 first performs the adjusting step S21, and the tubular crystal T is heated by the laser R, so that the double-fiber crystal fiber 1 starts the diffusion and integration process again, wherein the power of the laser R The curve is the second power curve P2 (as shown in FIG. 5), and the value of the second power curve P2 is lower than the value of the first power curve P1, so that the crystal fiber 11 and the glass capillary 12 are small. The mutual diffusion of the amplitude is used to reduce the core diameter value of the double-fiber crystal fiber 1, and the core of the double-fiber crystal fiber 1 is kept uniform and continuous. Then, the determining step S22 is performed, and the instant image of the double-fiber crystal fiber 1 is obtained by the crystal fiber manufacturing device A, and the user and the manufacturing program can interpret the core of the double-fiber crystal fiber 1 from the instant image. The diameter value, at this time, since the core diameter value has not been reduced to 2 micrometers, after the diffusion and mutual integration process is finished, the adjusting step S21 is performed to start the diffusion and mutual fusion process again, wherein the lightning The power curve of the R is the third power curve P3 (as shown in FIG. 5), and the value of the third power curve P3 is lower than the value of the second power curve P2, so that the fiber of the double fiber clothing crystal fiber 1 The core diameter can be further reduced; then the determining step S22 is performed, and if the core diameter value has been reduced to 2 micrometers, the diffusion and mutual fusion process is terminated to form the near-monomodal double-fiber crystal fiber 2.

In summary, the method for manufacturing the near-unimodal double-fiber crystal fiber of the present invention first forms the double-fiber crystal fiber 1 having a larger core diameter by the crystal fiber preparation program S1, and then the core is adjusted. The process S2 repeats the diffusion and fusion process of the double-fiber crystal fiber 1 , and the laser power value of the core adjustment program S2 is lower than the laser power value of the crystal fiber preparation program S1, and the core adjustment program The laser power value of S2 is successively decreased until the core diameter of the double-fiber crystal fiber 1 is reduced to the near-monomodal core diameter value to form the near-monomodal double-fiber crystal fiber 2. Therefore, the method for manufacturing the near-monomodal double-fiber crystal fiber of the present invention can successfully manufacture the near-monomodal double-fiber crystal fiber 2, wherein the core material of the near-monomodal double-fiber crystal fiber 2 is The yttrium aluminum garnet crystal, the core diameter value of the near-monomorphic double-fiber crystal fiber 2 can be reduced to the near-unimodal core diameter value and the core diameter is uniform.

Furthermore, the core adjustment program S2 of the present invention can adjust the core diameter value of the existing double-fiber crystal fiber to form a processing method of the double-fiber crystal fiber, and the diffusion integration is started again by the adjusting step S21. Process, and successively reducing the laser power value, so that the ion diffusion effect of the double-fiber crystal fiber 1 is reduced, not only reducing the core diameter value of the double-fiber crystal fiber 1, but also making the fiber-optic fiber 1 The core diameter value is more adjustable. And determining, by the determining step S22, whether the core diameter of the double-fiber crystal fiber 1 is reduced to the predetermined diameter value, wherein the predetermined diameter value may be greater than or equal to the near-unimodal core diameter value, where "The predetermined diameter value is equal to the near-unimodal core diameter value" as an example. If the determination is "Yes", the diffusion and mutual fusion process is terminated to form the near-monomodal double-fiber crystal fiber 2; If the value is NO, the laser power value is first lowered after the diffusion and mutual integration process is completed, and the adjustment step S21 is performed. Therefore, the method for processing the double-fiber crystal fiber of the present invention can reduce the core diameter value of the existing double-fiber crystal fiber to the near-monomodal core diameter value to form a near-monomodal double-fiber crystal fiber.

The main features of the method disclosed by the present invention are listed below by the technical means disclosed above:

First, since the core diameter value of the double-fiber crystal fiber 1 can be reduced to the near-unimodal core diameter value, and the laser power value of the diffusion and mutual fusion process is successively decreased, the present invention has " The gain ion absorption boosts the power of the pump source and the "laser threshold power" is reduced.

Secondly, since the core diameter value of the near-monomorphic chromium-doped double-fiber crystal fiber can be reduced to the near-unimodal core diameter value, the number of modes of light transmitted in the crystal fiber is reduced, so that the energy output of the light is made. The distribution is close to a single mode fiber, and therefore, the present invention has the effect of reducing modal transmission loss (Transmission Loss).

Thirdly, since the core diameter value of the near-monomorphic chromium-doped double-fiber crystal fiber can be reduced to the near-unimodal core diameter value, the present invention can not only communicate the communication band for the chromium-doped crystal fiber. It is maintained at 1.3 to 1.6 microns and has the effect of improving the conversion efficiency of the spontaneous emission amplification source.

Fourthly, since the core diameter value can be reduced to the near-monomodal core diameter value and the core diameter is uniform, the insertion loss (Insertion Loss) caused by the different core cross-sectional areas is reduced, and therefore, the present invention has an insertion The effect of reduced loss.

Fifth, by repeating the diffusion and integration process and decreasing the laser power value successively, the gain of the double-fiber crystal fiber can be improved and the ultra-wideband characteristic can be maintained. Therefore, the invention is easy to implement and low in cost. The effect.

In summary, the manufacturing method or the processing method disclosed by the present invention can solve the problem that the core diameter value cannot be reduced to the near-unimodal core diameter value for a long time, and the near-monomorphic chromium-doped double-fiber garment is further reduced. Crystal fiber is developed as a high-efficiency, low transmission loss and self-generated radiation amplification source for all-optical domains, fiber laser or ultra-wideband amplifier.

While the invention has been described in connection with the preferred embodiments described above, it is not intended to limit the scope of the invention. The technical scope of the invention is protected, and therefore the scope of the invention is defined by the scope of the appended claims.

[this invention]

1. . . Double fiber clothing crystal fiber

11. . . Crystal fiber

12. . . Glass capillary

2. . . Near-unimodal double-fiber crystal fiber

A. . . Crystal fiber manufacturing device

R. . . Laser

T. . . Tubular crystal

P1. . . First power curve

P2. . . Second power curve

P3. . . Third power curve

S1. . . Crystal fiber preparation program

S2. . . Core adjustment program

S21. . . Adjustment steps

S22. . . Judgment step

[知知]

9. . . Double fiber clothing crystal fiber

91. . . Crystal fiber

92. . . Glass capillary

93. . . Tubular crystal

R. . . Laser

Figure 1: Schematic diagram of a conventional method for producing a double-fiber crystal fiber.

Fig. 2 is a graph showing the core diameter change of the conventional method for manufacturing a double fiber clothing crystal fiber.

Fig. 3 is a schematic view showing the system of the preferred embodiment of the method for producing a near-simultane double-fiber crystal fiber of the present invention.

Fig. 4 is a flow chart showing a preferred embodiment of the method for producing a near-simular dual-fiber crystal fiber of the present invention.

Fig. 5 is a graph showing the power curve of a preferred embodiment of the method for producing a near-simultane double-fiber crystal fiber of the present invention.

S1. . . Crystal fiber preparation program

S2. . . Core adjustment program

S21. . . Adjustment steps

S22. . . Judgment step

Claims (14)

A method for manufacturing a near-single-mode double-fiber crystal fiber comprises: a crystal fiber preparation process for performing a diffusion and mutual fusion process to prepare a double-fiber crystal fiber; and a core adjustment program The double-fiber crystal fiber re-does the diffusion and fusion process at least once until the core diameter value of the double-fiber crystal fiber is reduced to a near-unimodal core diameter value to form a near-monomodal double-fiber crystal Fiber; wherein the laser power value of each of the diffusion and mutual fusion processes is successively decreased. According to the manufacturing method of the near-single-mode double-fiber crystal fiber according to the first aspect of the patent application, wherein the laser power adjustment process performs the diffusion power conversion process, and the laser power value is lower than the crystal fiber preparation program for the diffusion. The laser power value of the integration process. According to the manufacturing method of the near-single-mode double-fiber crystal fiber according to the first aspect of the patent application, wherein the diffusion and integration process of the core adjustment program is repeated several times, the diffusion and integration process is performed. The laser power value is successively reduced. The method for manufacturing a near-unimodal double-fiber crystal fiber according to claim 1, wherein the crystal fiber preparation process is irradiated by a laser to a tubular crystal to generate heat radiation, and a crystal fiber and a crystal fiber are used. The glass capillary begins the diffusion and mutual fusion process, and the double-fiber crystal fiber is formed after the diffusion and mutual fusion process is completed. The method for manufacturing a near-unimodal double-fiber crystal fiber according to claim 1, wherein the core adjustment program comprises: an adjusting step of restarting the diffusion from the double-fiber crystal fiber again The melting process reduces the core diameter of the double-fiber crystal fiber, wherein the laser power value of the diffusion and fusion process of the adjusting step is lower than the laser power value of the previous diffusion and integration process; and a judgment a step of determining whether the core diameter value of the double-fiber crystal fiber is reduced to the near-unimodal core diameter value, and if the determination is yes, ending the diffusion and mutual fusion process to form the near-simple mode double If the fiber-optic crystal fiber is judged to be no, the adjustment step is performed after the diffusion and mutual fusion process is completed. The method for manufacturing a near-monomodal double-fiber crystal fiber according to the first aspect of the patent application, wherein the core material of the double-fiber crystal fiber is a yttrium aluminum garnet crystal. The method for manufacturing a near-unimodal double-fiber crystal fiber according to the first, second, third, fourth, fifth or sixth aspect of the patent application, wherein the variation of the laser power value is maintained at ±0.1%. According to the manufacturing method of the near-single-mode double-fiber crystal fiber according to the first, second, third, fourth, fifth or sixth aspect of the patent application, wherein the judging step is to observe the double-fiber crystal fiber by the instant image monitoring technology. The instant image is for a user or a manufacturing program to monitor the core diameter value of the fiberglass fiber to determine whether to perform the adjustment step. A method for processing a double-fiber crystal fiber comprises: an adjusting step of performing a diffusion and mutual fusion process by a pair of fiber-optic crystal fibers, thereby reducing a core diameter of the fiber-optic fiber, wherein the adjusting The laser power value of the step is lower than the laser power value of the diffusion and fusion process during the manufacturing of the double fiber crystal fiber, and if the adjustment step is not performed for the first time, the laser power value of the diffusion and integration process is lower than a laser power value of the last diffusion process; and a determining step of determining whether the core diameter value of the fiberglass fiber is reduced to a predetermined diameter value, and if the determination is yes, ending the diffusion The mutual fusion process is performed to form a near-monomodal double-fiber crystal fiber. If the determination is negative, the adjustment step is performed after the diffusion and mutual integration process is completed. The method for processing a double-fiber crystal fiber according to claim 9, wherein the predetermined diameter value is equal to a near-monomodal core diameter value. The method for processing a double-fiber crystal fiber according to claim 9, wherein the predetermined diameter value is greater than a near-monomodal core diameter value. According to the processing method of the double-fiber crystal fiber according to claim 9, wherein the core material of the double-fiber crystal fiber is yttrium aluminum garnet crystal. The method for processing a double-fiber crystal fiber according to claim 9, 10, 11 or 12, wherein the variation of the laser power value is maintained at ±0.1%. According to the processing method of the double-fiber crystal fiber according to claim 9, 10, 11 or 12, wherein the judging step is to observe an instant image of the double-fiber crystal fiber by a real-time image monitoring technology for a user. Or a manufacturing program monitors the core diameter value of the double-fiber crystal fiber to determine whether the adjustment step is performed again after the diffusion and mutual integration process is finished.