JPS60412A - 2-input light receiving device - Google Patents

Abstract

PURPOSE:To obtain a stable optical coupling system having a good workability by fixing two optical fibers symmetrically to the center line, and fixing them so as to be condensed to one point of a photodetector through two spherical lenses or plano-convex lenses or GRIN lenses. CONSTITUTION:A fiber fixing part 11 has optical fiber core inserting parts 1', 2', and nylon coated part inserting parts 6', 7' at symmetrical positions against the center line, and an optical fiber is inserted and stuck to them. A spherical lens holding part 12 for fixing spherical lenses 9, 10 for condensing a light from the optical fiber inserted through the inserting parts 1', 2' is provided on the tip of the fixing part 11. Also, a photodetector 16 for photodetecting a light from the lenses 9, 10 is provided on the tip of the holding part 12. In this case, the axes of the two optical fibers and the axes of the lenses 9, 10 are shifted so that the lights from the two optical fibers are condensed to one point of the photodetector 16. Such two input light photodetecting part is fixed by a pipe part 17 and a photodetector fixing ring 22, and a stable two input light photodetecting device having a good workability is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field of the Invention The present invention relates to a two-man power light receiving device for optical communication, which has good workability, can condense two man power light to one point of a light receiving element, is stable, and has high crystal efficiency. The present invention relates to a two-manpower light receiving device that can realize a coupling system.

(b) Conventional technology and problems FIG. 1 is a schematic diagram of a conventional two-manpower light receiving device.

In the figure, 1.2 is an optical fiber, 3 is a fiber fixing part, 4 is a lens, 5 is a light receiving element, 6.7 is a nylon cord) KL8 is a hole through which two optical fibers are passed.

In the conventional dual-power light receiving device, as shown in FIG. , 2 must be attached exactly, and the 7-eye fiber fixing part 3 must be lengthened. When passing the optical fibers 1 and 2, the optical fibers 1 and 2 may be twisted or broken as shown in FIG. 1(B), making manufacturing difficult. Also, as shown in the side view of FIG. 1(C), , When the optical fibers 1 and 2 are completely passed through the hole 8 through which the optical fiber is passed, the gap is large and there is a large amount of adhesive to secure the optical fibers 1 and 2 into the hole 8 through which the optical fiber is passed. As a result, stress is applied to the optical fibers 1 and 2 due to the contraction and expansion of the bonded optical fibers, and the positions of the optical fibers 1 and 2 are shifted back and forth. With this method, it is impossible to condense the two-manpower light to a single point on the light-receiving element 5, so it is difficult to couple the two-manpower light to the light-receiving element 5 with high efficiency.

(c) Purpose of the Invention In view of the above-mentioned drawbacks, the purpose of the present invention is to improve workability by eliminating the need to closely connect two optical fibers, and to condense two optical power beams to one point on a light-receiving element. To provide a two-manpower light receiving device capable of realizing a stable optical coupling state by allowing light to flow.

(d) Structure of the invention In order to achieve the above object, the present invention uses a lens for each two-power optical fiber as a structure of a two-power optical receiver,
Utilizing the characteristic of off-axis imaging of the lens, it is possible to focus the two-power beam onto a single point on the light receiving element, and it also eliminates the need to connect two optical fibers exactly together, improving work efficiency. It is characterized by

(e) Examples of the invention Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 is an explanatory diagram of a method of condensing two human-powered lights onto one point on a light receiving element according to the present invention.

1 and 2 in the figure are the same optical fibers as in Figure 1, 9.10
11 indicates a spherical lens, and 11 indicates a fiber fixing part.

As shown in Figure 2, the target position is 2.
Identify two optical fibers 1 and 2 [7. In front of them, spherical lenses 9 and 10 are provided at symmetrical positions with respect to the center line opening, and the center position of the spherical lenses 9 and 10 is set from the center axis of the optical fibers 1 and 2. Shift ° by Δx. In this way, if the light receiving element is placed at point A, the light from the optical fiber 1.2 can be focused on one point on the light receiving element.

When the i'l equation is created using the symbols shown in FIG. 2(C) to express the relationship of condensing light to one point, it becomes as shown in the following equation.

S1nθ=,5. ,,...°Songs°SongsSongsSongs-(
1) a=(”'nn-1)2A-3'2-n)r -r
+2rL+r ""2) b=, /7 kidney Y7...
・・・・・・・・・・・・・(3) C-5; Recapture J
(4) However, n is the refractive index of the lens. In this case, as the angle θ at which light enters the light receiving element (for example, APD or PIN) increases, the quantum efficiency τ decreases. Considering this, it is desirable that θ is 10' or less. θ=
The reduction in τ in the case of io' is about 0.1 dB. Here, when θ is 10° and the radius r of the spherical lens is 0.5, the parameters (a, b, c) are as shown in the table below. The table below shows two unique lens refractive indexes n=1.5 and 20.

In this case, the side 1 of the fiber 1h running section 11 is shown in Figure 1 (
By cutting obliquely as shown in B), the aberrations of the ball lenses 9 and 10 can be reduced, and reflection from the ends of the optical fibers 1 and 2 can also be reduced.

The structure of a two-manpower light receiving device that realizes the above relationship will be described below.

Figure 3 is a structural diagram of a two-manpower light receiving device according to an embodiment of the present invention, (5) is a cross-sectional view and side view of the fiber fixing part, (B)
(C) is a side view and sectional view of the plano-convex lens holder, (B) is 2
FIG. 2 is a cross-sectional view of a human power light receiving device.

In the figure, 1/2/ is the optical fiber insertion part, 6/4/ is the nylon coat insertion part, 11 is the fiber fixing part, and 9.10
is a spherical lens, 12 is a spherical lens holder, 13 +
14 C plano-convex lens, 15 plano-convex lens holder,
16 is a light-receiving element, 17 is a pipe section into which two human-powered light receiving sections are placed, 18 is a mounting flange, 19 is a nylon coat section,
20 is a PVC cord part (3φ), 21 is a protective tube,
(22 indicates a ring for fixing the light receiving element) First, the method for fixing the optical fiber will be explained.

As shown in FIG. 3 (4), the optical fiber core insertion portions 1/, 2/nylon coat insertion portion 6 are installed in the fiber fixing portion 11 so as to approximately correspond to the relative positions determined by the above equations (1) to (4). ′,
7', into which the optical fiber 1.2 is inserted and fixed with adhesive. At this time, the optical fibers are passed through the holes one by one, so it is easy to work with, and only a small amount of glue is needed, so there is no need to apply souffle to the optical fibers, resulting in high reliability. This work is similar to the first step in making optical connectors, and the same level of high reliability can be obtained.

Next, we will explain how to fix the spherical lenses 9 and 10. As shown in FIG. When the light-receiving element 16 is fixed in contact, the size of the spherical lenses 9 and 10, the mounting position to the spherical lens holder 12, and the thickness of the spherical lens holder 12 are determined so that the relative positions determined by equations (1) to (4) above are achieved. Sa determines.

At this time, the ceramic of the spherical lens holder 12 is processed before sintering, and is sintered after the lens is inserted.

Next, the identification method in the case of a plano-convex lens 0RIN lens will be explained using Figure 3 (C1). GRIN lenses are representative of plano-convex lenses because they have the same structure as plano-convex lenses except for their flat end surfaces. and explain.

After polishing and bonding the sides shown at the mouths of the plano-convex lenses 13 and 14 in parallel to the optical axis, they are press-fitted or inserted into the gold plate of the plano-convex lens holding part 15, and are brought into contact or with the metal.

In the case of metal fixation, metal vapor deposition may be performed on the side surfaces of the plano-convex lenses 13 and 14.

Next, the two-man power light receiving device will be explained using FIG. 3 0).

FIG.
Insert it into the pipe part 17 and fix it as shown. At this time, the light receiving element 16 is fixed with a light receiving element fixing/glue 22. Others are contact 1
Fixed at 1, etc.

Note that the PvC code section 20. The projection tube 21 is attached to the pipe 17. The thus obtained two-manpower light receiving device is attached using the flange 18.

The above description has mainly been made in the case of a spherical lens, but in the case of a plano-convex lens GRIN lens, a two-man power light receiving device can be constructed using the same method as in the case of a spherical lens.

In addition, one of the two human-powered lights (Kazuko efficiency of iW)
If the coupling efficiency (coupling efficiency) can be lowered, as shown in FIG. 9 and a large angle (θ) of 10°) f1/, the light may be focused on the focal point C on the light receiving element.

(f) Effects of the Invention As explained in detail above, the present invention has the effect of providing a two-man power light receiving device with a stable optical coupling system, high efficiency, high reliability, and good workability.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of a conventional two-manpower light receiving device, Fig. 2 is an explanatory diagram of a method of condensing two-manpower light to a single point on a light receiving element according to the present invention, and Fig. 3 is an implementation of the present invention. FIG. 4 is a structural diagram of an example of a two-manpower light receiving device, and is an explanatory diagram of a method of focusing two manpower lights on a single point on a light-receiving element as an application example of the present invention. In the figure, 1 and 2 are optical fibers, 3.11 is a fiber fixing part,
4 is a lens, 5 and 16 are light-receiving elements, 6 and 7 degrees 19 are nylon teeth, 8 is a hole for passing an optical fiber through, 9.10 is a spherical lens, 12 is a spherical lens bold part, 13.14U
Plano-convex lens, 15 is a plano-convex lens holding part, 17 is a pipe part, 18 is a mounting flange, 20 is a PVC cord part, 2
Reference numeral 1 indicates a retaining tube, and 22 indicates a ring for fixing the light receiving element. Figure 1 (A) Figure 2

Claims (1)

[Claims] A fiber fixing part having two optical fiber insertion holes at symmetrical positions with respect to the center line, and a fiber fixing part having two optical fiber insertion holes at the tips thereof, condensing light from two optical fibers passing through the optical fiber insertion holes in the fiber fixing part. A holder for fixing individual spheres, lenses, or plano-convex lenses or Green (G) LIN) lenses is provided, and a light-receiving element and its individual portion are provided at the tip of the stationery to receive light from the corresponding/×, and A two-manpower light receiving device characterized in that the axes of the two optical fibers and the axes of the two lenses are shifted so that light from the two optical fibers is focused on one point of the light receiving element.