JPH0570123B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method of manufacturing an optical connector ferrule that realizes coupling of optical fibers in connection and switching of optical communication lines.

(Prior Art) FIG. 7 is an explanatory view of an example of a conventional multi-core optical connector ferrule, in which A is a top view and B is a view taken along the line X--X in FIG.

In the drawing, 40 is a resin-molded optical connector ferrule, inside which is a multi-core optical fiber B.
are positioned and fixed on a straight line, and guide pin holes 41 for inserting guide pins 42 are provided on both sides thereof. The guide pin 42 has a diameter of 0.7 mmφ,
The typical pitch of the guide pin hole 41 is 3.6 mm.
In the meantime, for example, if it is a 5-core optical fiber, it will be pitched.
It has a structure in which five 0.3mm optical fibers B are positioned and fixed.

When coupling, the two guide pins 42 are inserted into the guide pin holes 41 of one optical connector ferrule, and the other optical connector ferrule is inserted to face this, thereby achieving simultaneous coupling of the optical fibers B. do. Thereafter, in the above-described coupled state, the ferrule 40 is fixed under pressure from the rear using, for example, a clamp 5 as shown in FIG. 5B, and housed in a cylindrical housing.

Further, in manufacturing such a multi-fiber optical connector ferrule, a molding pin and its positioning member are set in a mold, and an optical fiber guide hole and a guide pin hole are formed by resin molding such as epoxy resin.

(Problems to be Solved) The conventional multi-core optical connector ferrule described above had the following problems.

Since the material that directly positions the optical fiber is resin, dimensions change in the humidity and temperature atmosphere, making it difficult to maintain precise dimensions.

Although the optical fiber guide hole is formed by resin molding, molding pressure and positional deviation between the molding pin and the positioning member cause bending of the molding pin, that is, bending of the optical fiber guide hole, resulting in increased loss.

In the positioning connection, the guide pin is inserted into the guide pin hole of the ferrule, but since the metal guide pin is inserted into the resin-molded guide pin hole, the hole is easily subject to wear and damage. Furthermore, since it is easily deformed, it is difficult to maintain precise submicron dimensions, and it is difficult to achieve high-precision bonding.

Similarly, the thermal expansion of resin is significantly larger than that of quartz, which is the material of the optical fiber, and therefore internal loss tends to increase due to temperature changes.

When performing dimensional measurement evaluation, since it is a resin molded product, the end face edges are sagging, making it extremely difficult to measure accurately in submicron units, and as a result, it is impossible to evaluate high-quality optical connector ferrules.

(Means for Solving the Problems) The present invention solves the above-mentioned problems, and enables low-loss coupling of single mode fibers with a core diameter of 10 μm and an outer diameter of 125 μm, which are considered to be the most difficult to couple. This provides a method for manufacturing optical connectors that achieves ideal ultra-precision coupling, with the following characteristics:
In a method of manufacturing an optical connector ferrule that holds an optical fiber and realizes positioning and coupling, a guide groove substrate is created by forming a V-shaped groove for positioning the optical fiber and guide pin on a silicon substrate using a diamond wheel. Then, a guide plate made of a hard brittle material is bonded to this upper surface so as to expose a part of the optical fiber V-shaped groove to form an optical fiber guide hole and a guide pin hole, and an optical fiber is inserted into the optical fiber guide hole. The process involves inserting it, fixing it with adhesive, and polishing the end surface.

(Example) FIG. 1 is a perspective view of a guide capillary which is a main component of an optical connector ferrule obtained by the manufacturing method of the present invention.

The guide capillary 1 is constructed by superposing and bonding a guide plate 12 made of a hard brittle material such as silicon onto the upper surface of a guide groove substrate 11 made of silicon.

The guide groove substrate 11 is made by grinding the upper surface of the groove substrate made of silicon using a diamond wheel to form V holes for positioning optical fibers and guide pins.
Shape grooves 14, 13 are provided. Then, a guide plate made of a hard and brittle material such as silicon is superimposed and bonded on the upper surface to form an optical fiber guide hole and a guide pin hole. Above guide groove board 11
The length of the guide plate 12 to be superimposed on it is
The two are bonded via a thin film adhesive layer 16 made of, for example, low melting point glass, but when they are stacked with one end aligned, part of the guide pin V-shaped groove 13 and the optical fiber V-shaped groove 14 is exposed in the length direction.

As shown in FIG. 2, such a guide capillary 1 is assembled into a lower housing 21 made of plastic with its distal end protruding. In this state, the optical fiber B (see Fig. 3) is inserted into the optical fiber guide hole, fixed with adhesive, the upper cover housing 22 molded from plastic is placed on the exposed portion 15, and the end face is polished. By doing so, an optical connector ferrule as shown in FIG. 3 is formed.

At this time, the rear end of the lower housing 21 has a sixth
As shown in Figure B, a pressurizing part 23 is provided to pressurize and fix the optical connector ferrule with the clamp 5 when the optical connector ferrules are connected.
The area of the pressurizing part 23 is increased by integrally molding flange parts 21a on both sides of the rear part of the pressurizing part 1.

FIG. 5 is a longitudinal sectional view of an optical connector ferrule to which an optical fiber is adhesively fixed.

The lower housing 21 and the upper lid housing 22 that constitute the housing 2 are formed by plastic molding, and the lower housing 21 has a shape that covers the side surface of the guide capillary 1 housed therein, and the guide capillary is contained inside. 1 and a step 24 corresponding to the diameter of the optical fiber core A.
2 also has a step 2 corresponding to the diameter of the optical fiber core A.
4'.

The guide capillary 1 is assembled into the bottom of the lower housing 21 as described above, and at this time, the end of the guide capillary 1 is placed in contact with the contact surface 26 formed by the step 25 and adhesive is applied. Fix by.

Incidentally, by providing a groove 27 in the bottom corner of the lower housing 21 as shown in FIG. 7, it is effective for the adhesive to escape.

FIG. 5 is an explanatory diagram of the coupling of optical connector ferrules, where A shows the state before coupling and B shows the coupled state.

The optical connector ferrule 30 of the present invention described above has two
Connected using book guide pin 4, clamp 5
is fitted into the rear pressurizing part 23 of the housing 2 and pressurized and fixed. At this time, by forming a flange portion 21a at the rear of the housing 2 as shown in FIG. 4, the area of the pressurizing portion is increased. In the drawing, 3 is a rubber boot mounted on the optical fiber core A.

(Prototype example and evaluation) A silicon wafer was prepared, and a V-shaped groove for positioning the optical fiber guide and guide pin was continuously ground on the upper surface of the silicon wafer using a diamond wheel to create a guide substrate assembly. The same diamond wheels were used for all of the above. On the other hand, a flat silicon plate is separately prepared, the surface of which is oxidized in advance, and an adhesive layer of low melting point glass is formed into a thin film of about 0.1 μm by sputtering, etc., and it is placed on the guide substrate assembly at a predetermined position. The two were heated to a total temperature of about 500°C and cooled to join them together. Next, this integrated wafer of hard and brittle material was cut into chips of a predetermined shape to obtain a guide capillary.

As an example, the dimensions of the obtained guide capillary are 7 mm in width, 2.2 mm in thickness, 8 mm in total length, and 3 mm in exposed length. Also, the guide board has a diameter of 0.7mmφ.
The guide pin grooves are machined at a pitch of 3.6mm, and the five optical fiber guide grooves are machined at a pitch of 0.3mm.The angle of these V grooves is all constant, and was set at 60° in the prototype.

Next, the guide capillary was assembled into the lower housing, which had been molded in advance by injection molding, and fixed by adhesive. There are steps at the bottom of the lower housing, one of which is for positioning and fixing the guide capillary, and the other forming a wire fixing portion corresponding to the diameter of the optical fiber. The overall length of the lower housing was 13 mm, and the length of the core wire fixing part was 5 mm.

Further, as shown in FIG. 4, the tip of the guide capillary is slightly protruded from the housing to facilitate polishing. In the prototype, it was made to protrude by approximately 0.5 mm.

Five optical fibers are inserted into the guide capillary assembled in the lower housing obtained in this way and fixed with adhesive, and the upper cover housing is placed to form a multi-fiber optical connector ferrule. After heat curing, the end surface was polished.

The optical connector ferrule thus obtained was connected using two guide pins, fixed with a clamp, and evaluated. The optical fiber used was a single mode fiber with a core diameter of 10 μm and an outer diameter of 125 μm.

The coupling loss is very good with a matching agent of 0.18 dB on average at n=50, and the maximum is 0.53 dB.
and is very stable. Temperature characteristics are -30℃ to +70
The variation was within 0.1 dB in °C, confirming that the coefficient of thermal expansion was improved compared to that of conventional plastics.

In addition, it is extremely stable with fluctuations within 0.05dB in a moist heat test at 80°C, 95%, for 10 days, and deterioration is within 0.2dB in an attachment/detachment test at N = 200 times, with no wear or deformation. do not have.

Furthermore, due to the processing method, the V-groove is linear, there is no bending of the optical fiber in the guide capillary, and hard and brittle materials such as silicon are used, resulting in highly efficient processing with a grinding ratio of over 30,000. It is easy to perform precision machining, and the edges are sharp, making measurement very easy. Note that a low-viscosity resin that can be spin-coated may be used as the bonding thin film layer.

(Effects of the Invention) As described above, the present invention provides the following effects.

V by diamond wheel by using silicon material as guide capillary
Grinding of the shape groove is possible, achieving high precision and high mass productivity, and there is no dimensional change due to swelling of plastic molded products as in the past.

Since the optical fiber guide groove and the guide pin groove are formed by grinding, the bending of the optical fiber guide hole due to the bending of the molded pin as in the conventional case is significantly reduced.

In the conventional connection, a guide pin hole and a metal guide pin are connected by plastic molding, and the guide pin hole is easily deformed when the guide pin is attached or removed.However, in the present invention, this type of connection is avoided because a hard and brittle material is used. The deformity disappeared.

Since a hard and brittle material is used for the guide capillary that positions and fixes the optical fiber, the thermal expansion is significantly smaller than that of conventional plastic, and the compatibility with the optical fiber, which is quartz fiber, is significantly improved.

Because it is made from hard and brittle materials, burrs are less likely to form, making precise dimensional measurements easier.

Storing the guide capillary in the housing is effective in reinforcing the guide capillary.

The step formed in the lower housing makes it easy to position the guide capillary and fix the optical fiber.

By bonding the guide substrate and guide plate with a thin film of low-melting glass, it has become possible to form guide slots with high precision.

By forming a clamp processing part at the rear end of the lower housing, ease of assembly and uniformity of pressurization are improved.

By using the same tool and machining guide grooves at the same angle, improvements in mass production and precision machining were achieved.

By providing a groove in the bottom corner of the lower housing, there is a place for the adhesive to escape, and
Chamfering the bottom edge of the guide capillary is no longer necessary.

Mass productivity was significantly improved by forming continuous guide grooves on a single wafer and cutting the wafer into chips.

Note that although the above description has mainly been made regarding a multi-fiber optical connector ferrule, it goes without saying that the same can be applied to a single-fiber optical connector ferrule as well.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a guide capillary which is a main component of an optical connector ferrule obtained by the manufacturing method of the present invention. FIG. 2 is a perspective view of the guide capillary shown in FIG. 1 housed in the lower housing. 3 and 4 are perspective views of examples of optical connector ferrules obtained by the manufacturing method of the present invention. FIG. 5 is a longitudinal sectional view of the optical connector ferrule of the present invention with an optical fiber attached, FIG. 6 A is an explanatory diagram of the optical connector ferrule of the present invention before connection, and FIG. . FIG. 7 is a cross-sectional view of the lower housing with grooves provided at the bottom corners. FIG. 8 is an explanatory view of a conventional multi-core optical connector ferrule, in which A is a top view and B is a view taken along the line X--X in FIG. A...Optical fiber core wire, B...Optical fiber, 1
... Guide capillary, 11 ... Guide board,
12...Guide plate, 13...Guide pin groove, 14...Optical fiber guide groove, 2...Housing, 21...Lower housing, 22...Top cover housing, 23...Clamp pressure section, 24,2
4', 25...step, 5...clamp.

Claims (1)

[Claims] 1. A method for manufacturing an optical connector ferrule that holds an optical fiber and realizes positioning and coupling, in which a V-shaped groove for positioning the optical fiber and guide pin is formed on a silicon substrate using a diamond wheel. A guide groove substrate is prepared by using the same method, and a guide plate made of a hard brittle material is bonded to the upper surface of the substrate so that a part of the optical fiber V-shaped groove is exposed to form an optical fiber guide hole and a guide pin hole. A method for manufacturing an optical connector ferrule, which comprises inserting an optical fiber into a guide hole, fixing it with adhesive, and polishing the end face. 2 V-shaped grooves for positioning optical fibers and guide pins are continuously formed on one wafer made of silicon using the same diamond wheel to create a guide groove substrate assembly, and optical fibers V-shaped grooves are formed on this wafer. By joining a guide plate so that a part of the groove is exposed and cutting and dividing the assembly, a plurality of guide capillaries for positioning optical fibers and guide pins having optical fiber guide holes and guide pin holes are formed. 2. A method of manufacturing an optical connector ferrule according to claim 1, wherein the method comprises: obtaining an optical connector ferrule;