Search

CN-121978843-A - Optical fiber beam combiner structure based on single-mode optical fiber and super surface and preparation method thereof

CN121978843ACN 121978843 ACN121978843 ACN 121978843ACN-121978843-A

Abstract

The invention discloses an optical fiber beam combiner structure based on a single-mode fiber and a super surface and a preparation method thereof, which belong to the field of optical fiber beam combiners. The beam combiner mainly comprises a beam combiner structure, wherein the beam combiner structure comprises a single mode fiber and a side perforated single mode fiber, the end part of the single mode fiber is a coreless fiber, the coreless fiber is subjected to beveling treatment, micropores are formed in the side perforated single mode fiber, a super surface made of a silicon substrate is arranged at the micropores, the bevels of the coreless fiber face the micropore area of the side perforated single mode fiber, so that the output optical power among the single mode fiber, the coreless fiber and the micropore area of the side perforated single mode fiber is the largest, and the single mode fiber and the side perforated single mode fiber are solidified. The invention is mainly used for the optical fiber combiner.

Inventors

  • LI KEYI
  • ZHANG YANG

Assignees

  • 艾迪科技(山东)有限公司

Dates

Publication Date
20260505
Application Date
20260408

Claims (8)

  1. 1. The optical fiber beam combiner structure based on the single-mode optical fiber and the super-surface comprises a beam combiner structure (3) and is characterized in that the beam combiner structure (3) comprises a single-mode optical fiber (7) and a side perforated single-mode optical fiber (9), the end part of the single-mode optical fiber (7) is a coreless optical fiber (8), the coreless optical fiber (8) is subjected to beveling, micropores are formed in the side perforated single-mode optical fiber (9), the super-surface (6) manufactured by a silicon substrate is arranged at the micropores, the bevel of the coreless optical fiber (8) faces the micropore area of the side perforated single-mode optical fiber (9), so that the output light power among the single-mode optical fiber (7), the coreless optical fiber (8) and the micropore area of the side perforated single-mode optical fiber (9) is the largest, and the single-mode optical fiber (7) and the side perforated single-mode optical fiber (9) are solidified.
  2. 2. The optical fiber combiner structure based on single-mode fibers and super surfaces according to claim 1, further comprising a pump source (2) and a gain fiber (4), wherein the pump source (2) is connected with the single-mode fibers (7), a gold reflector (1) is arranged at the input end of the side-perforated single-mode fibers (9), the gain fiber (4) is connected with the output end of the side-perforated single-mode fibers (9), and the gain fiber (4) is connected with the fiber Bragg grating (5).
  3. 3. The optical fiber combiner structure of claim 1, wherein the super surface (6) is composed of a periodic sub-wavelength structure made of silicon material, the periodic sub-wavelength structure has a structure period of 400nm-500nm, the unit is a rectangular silicon column, the unit size is 200nm-300nm, and the thickness is 800nm-1000nm, for focusing and coupling incident light to the core of the optical fiber.
  4. 4. The preparation method of the optical fiber combiner structure based on the single-mode fiber and the super surface is characterized by comprising the following steps of: S1, selecting a section of coreless optical fiber (8) with the length of 200 mu m, grinding the side edge of the coreless optical fiber by using a grinding disc at an angle of 30-40 degrees, and grinding the coreless optical fiber (8) to form an inclined section; S2, selecting a section of single-mode fiber, wherein one end of the single-mode fiber is aligned and welded with the cylindrical surface of the grinded coreless fiber (8), and the other end of the single-mode fiber is connected with a pumping source; s3, selecting a section of single-mode fiber in addition, and punching micropores by using a femtosecond laser system; S4, manufacturing a super surface (6) on the silicon substrate by adopting electron beam lithography, wherein the structural period is 450nm, the unit is a rectangular silicon column, the unit size is 250nm, and the thickness is 900nm; s5, aligning the output end of the coreless optical fiber (8) with the micropore area of the side perforated single-mode optical fiber (9) on a three-dimensional adjusting frame, determining the optimal position by observing the maximization of the output optical power, and then curing the two sections of single-mode optical fibers by adopting UV (ultraviolet) glue.
  5. 5. The method of claim 4, wherein the single-mode fiber has an outer diameter of 125 μm and a core diameter of 9. Mu.m.
  6. 6. The method for preparing the optical fiber combiner structure based on the single-mode optical fiber and the super surface according to claim 4, wherein the coreless optical fiber (8) has the length of 200 μm and the outer diameter of 125 μm, and is matched with the outer diameter of the single-mode optical fiber so as to be convenient for alignment welding.
  7. 7. The method of manufacturing a fiber combiner structure based on single mode fibers and a super surface according to claim 4, characterized in that the phase distribution function phi (x, y) of the super surface (6) compensates the aberration generated by the cylindrical lens effect of the single mode fiber (9) passing through the side hole after phase modulation of the diverging beam from the chamfer of the coreless fiber (8) and finally focuses into a Gaussian spot at the core position that is highly matched to the fundamental mode of the fiber.
  8. 8. The method of manufacturing a fiber combiner structure based on single mode fiber and super surface according to claim 4, wherein the aperture of the micro-holes is 45 μm-55 μm, larger than the caliber of the super surface (6) to allow for controllable assembly gap, and the depth is controlled to 55 μm-60 μm to ensure that the upper boundary of the fiber core is reached without damaging the fiber core, thereby maintaining the mechanical strength and the integrity of the guided wave structure of the fiber while forming a low loss optical window.

Description

Optical fiber beam combiner structure based on single-mode optical fiber and super surface and preparation method thereof Technical Field The invention relates to the field of optical fiber beam combiners, in particular to an optical fiber beam combiners structure based on a single-mode optical fiber and a super surface and a preparation method thereof. Background The optical fiber beam combiner is used as a key passive device of an optical fiber laser, an amplifier and a multi-wavelength system, has the function of combining multiple paths of optical signals into one path of output with high efficiency and low loss, and is an important technical means for realizing high-power, multi-band and multi-mode optical field synthesis. Along with the development of the fiber laser system to high power, narrow linewidth and multi-wavelength directions, higher requirements are put on the performance of the combiner, and not only are high coupling efficiency and low insertion loss required, but also excellent thermal stability, structural compactness and environmental adaptability are required. At present, the traditional optical fiber beam combining technology mainly comprises the following steps of heating, melting and stretching after a plurality of optical fibers are arranged side by side in a compact way, so that optical fiber cores are gradually close to each other, and mutual coupling of optical fields is realized. The method has the advantages of relatively mature process and lower cost, but has the following outstanding problems of serious mode field mismatch, particularly remarkable reduction of coupling efficiency when the mode of the combined optical fiber is inconsistent or the wavelength difference is large, poor thermal stability, fragile fuse cone area structure, easiness in being influenced by thermal stress under high-power pumping, performance degradation and even damage, and limited application range, and is difficult to be suitable for the combined optical fiber with large mode field area or the combined optical fiber with few modes and sensitive to the pumping optical power density. And the multi-core optical fiber coupler realizes optical energy exchange by utilizing evanescent field coupling among fiber cores in the multi-core optical fiber. The structure has higher integration level, but has the following limitations that the preparation process is complex, the drawing, aligning and packaging process of the multi-core optical fiber is difficult, the yield is low, the crosstalk is difficult to inhibit, the inter-channel crosstalk is easy to cause, the signal independence is influenced, the flexibility is insufficient, the structure is fixed, and the dynamic adjustable or selective wavelength beam combination is difficult to realize; The side polishing/side punching coupler is characterized in that a light input window is manufactured on the side of an optical fiber through mechanical polishing or laser processing, and light injection is realized through external lenses or optical fiber butt joint, and the method can avoid the heat problem of a fused cone structure, but has the following defects that the alignment precision requirement is extremely high, the side coupling is required to be aligned in a three-dimensional precision way, the assembly difficulty is high, the long-term stability is poor, the mechanical strength is damaged, the mechanical strength of the optical fiber can be obviously reduced through polishing or punching, the breakage is easy to cause, the coupling efficiency is limited, and the traditional lens coupling mode is difficult to realize high-efficiency and low-aberration mode matching. In recent years, the super surface is used as an emerging two-dimensional nano optical device, and by virtue of the flexible regulation and control capability of the super surface on the amplitude, the phase and the polarization of a light field, the super surface has obvious advantages in the aspects of beam shaping, focusing, deflection and the like. The super-surface structure can realize high-efficiency light field control through the design of the sub-wavelength scale unit, has the characteristics of small volume, easy integration, high design freedom degree and the like, and provides a new path for optical fiber coupling and beam combination. Meanwhile, the femtosecond laser micromachining technology can realize high-precision and low-damage three-dimensional microstructure preparation in or on the surface of a transparent material due to the cold machining characteristic of the technology, and is widely applied to manufacturing of fiber gratings, microcavities and side coupling structures. The prior art still lacks an optical fiber beam combination scheme which not only can realize high-efficiency and low-loss beam combination, but also has good thermal stability and structural robustness. Therefore, a novel optical fiber combiner based on a single-mode optical fiber and a super sur