CN102520490A - Large-mode-area single-mode fiber connector and manufacture method - Google Patents

Abstract

The invention discloses a single-mode optical fiber connector with a large mode area and a manufacturing method. The connector includes a ferrule, the periphery of the ferrule is a connection fixing head, the center hole of the ferrule is a single-mode fiber, and the single-mode fiber is fused with a graded index lens made by step-type multimode fiber through thermal diffusion. Color rings are formed on the rubber boot. The manufacturing process of the connector: the step-type multi-mode fiber is thermally diffused by the core doping element to form a graded lens with a reduced refractive index radially outward, and then welded, cut and fixed with the single-mode fiber In the center hole of the pin, the outer end is flush with the end face of the pin, and the end face of the pin is ground and polished; a color ring is printed on the rubber boot, and the pin is equipped with a fixed head. The invention has the advantages that the structure is simple and easy to manufacture, the end face is easy to keep clean, the light-passing area is large, and it can realize mating connection with other existing optical fiber movable connectors.

Description

Single-mode optical fiber connector with large mode area and manufacturing method

technical field

The invention relates to a large-mode area single-mode optical fiber connector and a manufacturing method thereof, which belong to the field of optical fiber technology and optical fiber communication technology.

Background technique

In the actual use of optical fibers, it is often necessary to connect two sections of optical fibers to each other. There are two types of implementation methods: fusion splicing and active connectors. The fusion splicing method to achieve optical fiber docking has the advantages of low insertion loss and high reliability, but once the optical fibers are fused together, it is permanent (unless it is cut off), so its flexibility is very poor. The optical fiber active connector is a component that realizes the detachable connection between the optical fiber and the optical fiber. Through it, the two end faces of the optical fiber can be precisely connected, so that the optical energy output by the transmitting optical fiber can be coupled to the receiving optical fiber to the maximum extent. In the optical fiber movable connector, the optical fiber is pre-fixed in the connector, and can be plugged and unplugged at any time during use, which is very convenient. Although fiber optic active connectors introduce additional insertion loss compared with fusion splices, optical fiber active connectors are still widely used in optical fiber communications and other optical fiber applications. Optical fiber active connectors are the most widely used optical passive components in optical fiber systems, and are widely used in communications, local area network (LAN), fiber-to-the-home (FTTH), high-quality video transmission, optical fiber sensing and test instruments. With the continuous development of optical fiber technology, various types of optical fiber active connectors have appeared one after another. According to incomplete statistics, there are currently dozens of types of optical fiber active connectors, among which FC, SC, LC and MT-RJ are the most commonly used connectors. The use of these optical fiber active connectors can realize the butt joint of the same type of optical fiber, but the butt joint of different types of optical fibers will introduce a large insertion loss. In addition, the optical aperture of existing optical fiber active connectors is the fiber core diameter, and for single-mode fibers, the core diameter is generally very small. For example, the core diameter of a common 1550nm single-mode fiber is about 10 microns. If there is dust on the end face of the movable connector, it is easy to block the light aperture and make it impossible to pass light. Therefore, it is necessary to ensure that the end face of the optical fiber active connector is clean, and if there is dust, it must be wiped with a special tool. Furthermore, when the existing optical fiber active connector is used to transmit high-power optical signals, the end face of the active connector is often damaged due to the high power density of the end face. In order to solve the above problems, one method is to bond a graded index of refraction (GRIN) lens to the front end of the single-mode fiber to expand and collimate the beam emitted from the single-mode fiber. The effect of this method is obvious, but the graded index lens must be precisely aligned with the optical fiber before bonding, and it is difficult to combine with the existing manufacturing process of the optical fiber active connector. Another method is to process a spherical microlens at the front end of the single-mode optical fiber by mechanical processing or thermal fusion. Although this method realizes the integration of the single-mode fiber and the beam expander lens, it cannot realize the physical contact of the end face of the docked fiber, that is, it cannot eliminate the Fresnel reflection, and it is difficult to control the return loss, so it has not been widely used. Splicing a section of multimode fiber with a graded index of refraction at the front end of the single-mode fiber is another way to expand the mode field of the single-mode fiber, but the beam expansion effect is limited due to the existence of the cladding of the multimode fiber. Therefore, there is still a need for a method of manufacturing single-mode optical fiber connectors with large-mode areas using existing processes, and a marking method is also required to flexibly connect large-mode-area single-mode optical fiber connectors with ordinary optical fibers. device to distinguish.

Contents of the invention

The purpose of the present invention is to provide a single-mode optical fiber connector with a large mode area and a manufacturing method. The single-mode optical fiber connector with large-mode area not only can easily keep the end face clean, and the light transmission is not easily affected by the external environment, but also can be mated and connected with other existing optical fiber active connectors, and the manufacturing method is simple.

The present invention is achieved through the following technical proposals. A single-mode optical fiber connector with a large mode area includes a metal or ceramic ferrule, and a connection fixing head is arranged in the circumferential direction of the ferrule. The single-mode optical fiber is fixed by the adhesive inside, and the rubber boot is nested on the single-mode optical fiber outside the ferrule. The outer end of the refractive index gradient lens is flush with the vertical end face or inclined end face of the ferrule, and a color ring is made on the rubber boot of the single-mode fiber optic connector.

The manufacturing method of the above-mentioned single-mode optical fiber connector with large mode area is characterized in that it includes the following process:

1) A step-type multimode fiber with the same diameter as the cladding diameter of the single-mode fiber is thermally diffused at a temperature of 1100°C to 1150°C to form a radially outwardly reduced refractive index along the central axis. gradient lens;

2) using an optical fiber fusion splicer to fuse the single-mode optical fiber and the graded index lens prepared in step 1);

3) According to the condition that the light emitted from the single-mode optical fiber passes through the graded-index lens, the diameter of the beam reaches the maximum at the end face of the graded-index lens, is the same as the diameter of the graded-index lens, and is parallel to its central axis. The rate gradient lens is cut off at a predetermined length;

4) Fix the single-mode optical fiber and the graded index lens assembly in the central stepped hole in the metal or ceramic ferrule with an adhesive, the end face of the graded index lens is flush with the end face of the ferrule, and is aligned with the end face of the ferrule Carry out grinding and polishing treatment, configure threaded fixing head in the circumferential direction of the pin, nest rubber boots on the single-mode optical fiber and print color rings, and make a large-mode area single-mode optical fiber connector.

Compared with the prior art, the advantage of the present invention is that the manufacturing method of the single-mode optical fiber connector provided by the present invention has the following significant advantages: 1) The light beam can fill all the light-passing areas of the gradient index lens, and the beam expansion effect is good; 2 ) can realize the docking of different types of single-mode optical fibers, and the insertion loss is low; 3) the structure is simple, the reliability is strong, and it can be well combined with the existing manufacturing process of optical fiber connectors, and the manufacturing cost is low, suitable for mass production ; 4) It can realize the physical contact butt joint of the end face of the optical fiber, especially when the end face is ground into an oblique angle, it has the advantage of large return loss; 5) The appearance mark is easy to identify; 6) It is suitable for popularization and application.

Description of drawings

Accompanying drawing 1 is the structural diagram of the optical fiber connector involved in the present invention. In Fig. 1, 101 is a pin; 102 is a metal nut; 103 is an identification color ring; 104 is a rubber boot; 105 is an optical cable, which contains a single-mode optical fiber.

Accompanying drawing 2 is a schematic diagram of the internal structure of the ceramic ferrule in accompanying drawing 1. Among them, 201 is a ceramic ferrule; 202 is a single-mode optical fiber; 203 is the gap between the single-mode optical fiber and the ceramic pin hole, which is filled with adhesive; 204 is the fusion surface of the single-mode optical fiber and the gradient index lens; 205 is a graded refractive index lens.

Accompanying drawing 3 is the schematic diagram of using two optical fiber connectors made by the method of the present invention to carry out single-mode optical fiber docking. Among them, 301 and 306 are single-mode optical fibers; 302 and 305 are fusion splicing surfaces; 303 and 304 are graded refractive index lenses. The dotted line in the figure represents the diameter change of the beam in the graded index lens.

Detailed ways

The specific implementation manners of the present invention will be described in detail below in conjunction with the accompanying drawings. As shown in Figure 2, the single-mode optical fiber 202 is a standard single-mode communication optical fiber (G652), with a core diameter of 8.2 μm, a cladding diameter of 125 μm, and a numerical aperture of 0.14. First remove its protective coating, and then use a fiber optic cutter to cut its end face perpendicular to its axis. The graded index lens 205 is made by using Nufern MM-S105/125-15A step-index multimode fiber through high-temperature treatment. MM-S105/125-15A has a core diameter of 105 μm, a cladding diameter of 125 μm, and a numerical aperture of 0.14. First remove its protective coating, place it in a high-temperature tubular heating furnace, and heat it at 1100°C for 30 minutes. In the high temperature state, the germanium element in the fiber core of MM-S105/125-15A will diffuse outward from the centerline of the fiber along the radial direction, forming a graded lens whose refractive index decreases radially outward from the central axis.

Use a fiber cutter to cut the end face of the graded index lens 205 perpendicular to its axis. Afterwards, the single-mode optical fiber 202 and the graded index lens 205 after the end face treatment are put into the optical fiber fusion splicer to fuse the two optical fibers together. Cut the graded index lens 205 at a distance of 400 microns from the fusion surface (204) with a fiber cutter to form a mirror surface perpendicular to its axis on the end surface. The ceramic pin 201 adopts a 2.500mm conventional zirconia ceramic pin, and the inner diameter of the central hole is 126 microns. Inject ND353 epoxy glue into the center hole of the ceramic ferrule 201, and then insert the above-mentioned single-mode optical fiber 202 and refractive index gradient lens 205 into the center hole of the ceramic ferrule 201, and the end face of the refractive index gradient lens 205 and the ceramic ferrule The end faces of the needles 201 are flush. Using an ultraviolet lamp to perform curing treatment, an adhesive layer is formed in the gap 203 between the single-mode optical fiber 202 and the graded index lens 205 and the ceramic ferrule 201 .

In this embodiment, a commercially available standard FC-type optical fiber connector assembly is used, and its various indicators conform to the indicators of the FC-type optical fiber connector specified in the "Communication Industry Standard of the People's Republic of China YD/T 1272.4-2007".

The ceramic ferrule and the FC type optical fiber connector assembly including the single-mode optical fiber 202 and the graded index lens 205 are assembled into an FC type optical fiber connector. Use an optical fiber grinder to perform grinding and polishing; the end face is perpendicular to the central axis of the ceramic ferrule 201, and then an optical fiber connector corresponding to the standard FC/PC is obtained. According to the marking method of the large-mode-area single-mode optical fiber connector provided by the present invention, it is recorded as FC/PC/L, or FC/PC-L; /APC corresponding fiber optic connector. According to the marking method of the large-mode-area single-mode optical fiber connector provided by the present invention, it is recorded as FC/APC/L, or FC/APC-L.

For FC/PC fiber optic connectors, it is customary to use black rubber boots; for FC/APC fiber optic connectors, it is customary to use green rubber boots. According to the marking method of the large-mode-area single-mode optical fiber connector provided by the present invention, a red color ring 103 is added to the black or green rubber boot 104 to indicate the difference from ordinary FC/PC or FC/APC optical fiber connectors . With the above marking method, the color contrast is sharp, and users can easily distinguish the large-mode-area single-mode optical fiber connector involved in the present invention from the standard FC optical fiber connector.

For other existing types of optical fiber connectors, the method for manufacturing and marking the large-mode-area single-mode optical fiber connector provided by the present invention can be applied in a method similar to that given in this embodiment.

It is clear to those skilled in the art that the idea of the present invention can be implemented in other ways than the specific implementations listed above.

Claims (2)

1. the long-pending single-mode optical fiber connector of a big die face; It comprises contact pin metal or pottery, connects fixed head in the circumferential configuration of contact pin, in the contact pin central stepped by the affixed single-mode fiber of cementing agent; Nested rubber tail cover on the single-mode fiber outside the contact pin; It is characterized in that, the single-mode fiber welding diameter multimode stepped-index optical fiber identical in the contact pin with this single-mode fiber cladding diameter, this multimode stepped-index optical fiber is and outwards reduces the gradually changed refractive index lens; The outer end that outwards reduces the gradually changed refractive index lens is concordant with the perpendicular end surface or the angled end-face of contact pin, puts at the rubber tail of single-mode fiber and is shaped on colour circle.

2. manufacturing approach by the long-pending single-mode optical fiber connector of the described big die face of claim 1 is characterized in that comprising following process:

1) multimode stepped-index optical fiber that diameter is identical with the single-mode fiber cladding diameter carries out the thermal diffusion of fibre core doped chemical under 1100 ℃～1150 ℃ of temperature, forms and radially outward reduces the gradually changed refractive index lens along central axis;

2) use optical fiber splicer that the gradually changed refractive index lens that single-mode fiber and step 1) make are welded together;

3) according to by the light of single-mode fiber outgoing after outwards reducing the gradually changed refractive index lens; Requirement reach beam diameter the gradually changed refractive index lensed endface reach maximum and identical with the diameter of gradually changed refractive index lens, simultaneously with the condition of its central shaft line parallel, the gradually changed refractive index lens are cut off at the predetermined length place;

4) with single-mode fiber and gradually changed refractive index lens assembly with in the central stepped of adhesive securement in metal or ceramic contact pin; The end face of gradually changed refractive index lens is concordant with the end face of contact pin; And the contact pin end face is carried out grinding and polishing handle; Circumferentially dispose the screw thread fixed head at contact pin, nested rubber tail overprint colour circle on single-mode fiber is processed the long-pending single-mode optical fiber connector of big die face.

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