JPH04110808A - Integrated optical fiber functional component - Google Patents

Abstract

PURPOSE:To enable small-sized integration by aligning optical axes of opposite GI optical fibers with each other and obtaining a spot size conversion type coupling system through a beam waist between the opposite GI optical fibers. CONSTITUTION:A successive body of GI optical fibers 5 is embedded in respective optical fiber grooves 3, the GI optical fibers 5 of specific length L are left at both end parts on the top surface of a substrate 2, and a groove 8 which has specific depth D and width is cut in the intermediate part. The width of an optical fiber holding part 7 and the length L of the fibers 5 are set in relation with the refractive index distribution form that the fibers 5 have and the length L of the fibers 5 which are held on the optical fiber holding part 7 while both ends are ground is set properly. Consequently, when light which is made incident on one side of a fiber 5 is projected on a gap shown by a groove 8, a beam waist is formed here to couple the opposite fibers 5 mutually with low loss.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention provides an integrated optical fiber functional component 10FC (Inte
rated 0ptical fiber func
For more information on tionalComponent, see
The present invention relates to a functional component that can suppress loss due to a gap when interposing a functional optical element or the like in an optical fiber waveguide for optical communication.

[Prior Art] An example of a conventional integrated optical fiber functional component (IOPCI) of this type is shown in FIG. 6. This example is used when interposing a functional optical element such as an optical isolator between optical fibers. Here, 100 is an optical fiber, and 200 is a distributed index lens.In this way, the distributed index lens 200 is used to obtain a parallel light beam 300 between them. By forming a parallel beam conversion system, the gap loss between the optical fibers 100 is kept low (suppressed).

[Problems to be Solved by the Invention] However, the conventional 10FC described above has the following problems.

(1) The diameter of the distributed index lens 200 is generally several n+m, and the diameter of the normal optical fiber 100 is 0.125.
If a plurality of such optical fibers 100 are arranged at a pitch of about 0.25 mm, it is difficult to form a multi-core parallel beam conversion system. is difficult.

(2) Since the distributed index lenses 200 arranged at opposing positions are provided independently from each other, it is necessary to align the optical axes between both lenses 200.

(3) It is also necessary to align the optical axes between the optical fiber 100 and the distributed index lens 200, which requires the use of an alignment jig, and requires a high level of skill to properly fix both. It takes.

The purpose of the present invention is to focus on the above-mentioned conventional problems and to solve them. Our objective is to provide an integrated optical fiber functional component that can suppress

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a groove having a predetermined length and diameter on both sides of a groove of a predetermined width provided on a substrate.
The optical fibers are arranged in parallel so as to face each other, and the optical axes of the opposing GI optical fibers are made to coincide with each other,
The present invention is characterized in that a spot size conversion type coupling system is obtained between the opposing GI optical fibers via a beam waist.

[For production]

According to the present invention, a plurality of parallel Gl optical fibers having predetermined lengths and diameters are disposed at opposite positions on both sides of the substrate through a groove in which a functional optical element or the like is interposed, and the optical axis thereof is are maintained in a consistent state, and the G.I.
When setting the length of the optical fibers, a beam waist exists between the opposing pairs of GI optical fibers, and bidirectional coupling can be obtained by converting the spot size, so each GI optical fiber has a distributed refractive index. It functions in place of a lens, can be miniaturized and integrated, is suitable for mass production, and can realize a spot size conversion type coupling system for multiple optical fibers at once. .

[Examples] Examples of the present invention will be described below in detail and specifically based on the drawings.

1 and 2 show one embodiment of the invention. In these figures, 1 is a board 10FC12 is a board constituting the 10FCI. 3 is a plurality of parallel optical fiber grooves formed on the substrate 2 by continuous processing, and 4 is a guide pin groove provided on both sides of the optical fiber groove 3 in the same direction. 5 is a GI optical fiber (graded index type optical fiber) embedded in each optical fiber groove 3 and held between the flat plate 6 and fixed with adhesive;
By arranging the I optical fiber 5 as shown in the figure, the G
A spot size conversion type coupling system is constructed by utilizing the characteristics of one optical fiber, as will be described later.

To do this, first, a continuous body of GI optical fibers 5 is buried in each optical fiber groove 3 as described above, and then GI optical fibers 5 of a predetermined length are left at both ends of the upper surface of the substrate 2. A groove 8 having a predetermined depth D (D>depth of optical fiber groove) and width is cut in the intermediate portion. In addition, the width of the optical fiber holding part 7 and the GI optical fiber 5 at this time
The length L is set in relation to the refractive index distribution form of the GI optical fiber 5, and the plurality of GI optical fibers 5 held in the optical fiber holding part 7 with both ends polished
By appropriately setting the length (corresponding to the width of the holding part), when the light incident from one side of the G1 optical fiber 5 is emitted toward the gap indicated by the groove 8, the beam waist is , and the opposing Gl optical fibers 5 can be coupled with low loss through the beam waist.

9 is a clamper for holding the guide bin 10 in the guide pin groove 4. As shown in FIG. 2, by fitting the guide pin lO into the guide pin groove 4 and attaching the clamper 9 from above as shown in the figure, the l0PCI is Optical fibers (not shown) provided on both sides can be maintained in a connected state. Although the guide pin groove 4 is not shown, it may be formed on the lower surface of the substrate 2.

In the 10F(:1) constructed in this way, the GI optical fibers 5 are buried in each of the parallel optical fiber grooves in advance, and the intermediate part thereof is removed together with the substrate 2 to form the groove 8. As shown, the axes of the GI optical fibers 5, which are separated into right and left parts and held by the holding section 7, are completely aligned, and there is no need for axial center adjustment as in the conventional example. As mentioned earlier, the length L of the optical fiber 5 is set so that the opposing GI optical fiber beams in the groove 8 are combined with the minimum loss through the beam waist, so that the light connected to the l0PCI It is possible to freely plan the number of fibers, that is, regardless of the number of GI optical fiber rows.

(A), (B) and (C) of FIG. 3 show the form in which TOPCI according to the present invention is actually applied. In (A), the optical connector 4 is connected to the multi-core tape fiber 100A.
00 is provided, and guide pins 10 are provided protruding from each optical connector 400, and these guide pins IO
It is sufficient to fit the guide pin groove 4 against the guide pin groove 4 from the opposite direction of the l0PCI, and then fix it with the clamper 9.

In (B), the guide pin IO continuous to the guide pin groove 4 of l0PCI is fixed in advance with a clamp 9. In this case, the guide pin 10 protruding from both sides of l0FC:1 is By inserting the connector 400 into a female hole (not shown), mutual alignment can be achieved. In addition, (C) is an example in which the 10PCI and the optical connector 400 are made into one package IA from the beginning, and the connection does not necessarily have to be done by fitting the guide pin into the guide pin groove (but it is also possible). Needless to say.

Figure 4 shows l0PCI and optical connector 40 as described above.
0 is shown coupled to the coupling surface 11. By being coupled in this way, individual 3M optical fibers 10
By performing distributed refraction on the light passing through the GI optical fiber 5 and forming a beam waist 20 in the middle, a spot size conversion type coupling system can be obtained. As can be seen from this figure, the height H2 of the substrate 2 and the height H2 of the flat plate 6 are
is preferably formed to match the corresponding height on the coupling surface 11 of the optical connector 400.

Thus, by embedding an optical element (not shown) in the parallel groove 8, one optical functional component such as an optical isolator, optical switch, optical coupler, optical tap, optical multiplexer/demultiplexer, optical multiplexer/brancher, etc. can be formed. It becomes possible. Especially (C) in Figure 3.
In the case of the form shown in , when manufacturing the 10FC, the 10FC and the optical connector are combined in pairs on the same processing line to ensure alignment of the guide pin grooves and optical fiber guide grooves. IO
It can be said that it is extremely suitable for mass production of optical functional parts using FC.

The present inventor further specified l0F as shown below.
As a result of conducting experiments with C, we were able to achieve good results with extremely low coupling loss.

10 optical fiber grooves and 2 optical fiber grooves on a 1.5 mm thick Si wafer
The guide bottle groove of the book was processed at a predetermined position, and a flat plate having a thickness of 0.5 mm was joined to form an optical fiber guide hole. Note that no flat plate is provided above the guide bin groove. Thus, the optical fiber groove has an outer diameter of 1
A Gl optical fiber having a diameter of 25 μm and a focusing constant g of about 2.8 mm was inserted and fixed with adhesive. Polish both ends of the optical fiber holding part to which the GI optical fiber is fixed, and
Parallel grooves were formed by grinding to a depth of approximately 1 mm. The total length of the substrate was approximately 2780 μm, and the length of the groove removed by polishing was approximately 1500 μm, and the optical fiber holders at both ends held approximately 640 μm long GI optical fibers for spot size conversion and coupling. . Then, ten SM optical fibers with an outer diameter of 125 tLm were inserted and fixed into the fiber holding portion of an optical connector manufactured on the same processing line, and the end faces were polished to form a multi-core optical connector.

A SUS clamp is installed on the outside of the l0FC, and the clamp holds 4 φ0.7mm guide bins on each side.
It was fixed under pressure so that it protruded by mm.

A 5M10 multi-core optical connector was coupled to this 10FC using matching oil, and a quartz glass coated with matching oil was inserted into the groove of the 10FC for testing.

In this state, we measured the overall coupling loss between the 10FC and the optical connectors on both sides, and found that the average for all fibers was approximately 0 at λ = 1.3] μm.
．． The loss was as low as 35 dB. The length of the groove where the optical fiber was removed by polishing was approximately 1500 μm.
The coupling loss during this time is estimated to be about 2 dB or less considering the loss of the 3M optical connectors on both sides, so it is possible to create a spot size conversion type coupling system that has low loss and can process multiple fibers at once. did it. Therefore, by using this, it becomes possible to form various optical functional parts. Furthermore, by optimizing the focusing constant g and processing accuracy, it is possible to aim for lower loss. In the case of this experiment, the spot size was 4.6 μm for the 3M optical fiber, expanded to a maximum of 40 μm for the GI optical fiber, and the beam waist was 1.
It is thought that the size can be reduced to about 5 μm.

In the above explanation, one 10FC was described, but in reality, mass production processing on a wafer scale is possible, and -
It has the great advantage of being able to be processed all at once.

Furthermore, in the above embodiment, the guide pin for coupling is pressed into the guide groove by a metal clamper, but l0
The connection between the FC and the optical connector is not limited to this, but any method may be used as long as it allows accurate mutual positioning, such as directly attaching a guide pin to the FC side by adhesive etc. Good too.

If the focal point of the l0FC becomes a problem, a space 12 of a certain length is created outside the GI optical fiber 5 as shown in FIG.
may be formed based on the design. Of course, it goes without saying that such a space may be formed on the optical connector side (not shown).

[Effects of the Invention] As described above, according to the present invention, (1) a spot size conversion coupling system can be formed in accordance with the dimensions of an optical fiber, so miniaturization and integration are possible.

(2) A spot size conversion coupling system can be realized by combining multiple optical fibers. (3) Compatibility of coupling with conventional optical connectors can be obtained.

(4) Using grinding, the lengthwise dimension of the space for interposing the GI optical fiber and optical functional components can be easily determined, and the conventional alignment work is not required.

(5) Since the continuous GI optical fiber is buried in the substrate with a continuous V-groove and then ground, there is no need for axial alignment as in the conventional case, and if necessary, it can be integrated with both connector parts. Can be manufactured.

(6) The structure is suitable for mass production processing because it has a structure that allows processing of a plurality of IOL''Cs at once on a wafer scale.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an example of the configuration of the 10FC of the present invention, FIG. 2 is a front view of the 10FC shown in FIG. 1, and FIG. 3 is an explanatory diagram showing various combinations of the 10FC of the present invention and an optical connector. Fig. 4 is a diagram of the path of the light beam of the spot size conversion coupling system in the coupled state of the l0FC of the present invention and the optical connector, Fig. 5 is an explanatory diagram of another embodiment (focal length guaranteed type) of the present invention, and Fig. 6 The figure is an explanatory diagram of a conventional parallel beam conversion system using 10FC. 1...l0FC. 2... Substrate, 3... Optical fiber groove, 4... Guide bin, 5... GI optical fiber, 7... Optical fiber holding part, 8... Parallel groove, 9... Clamper, 10... Guide bin, 20... Beam waist, 100... 3M optical fiber, 100A... Multi-core tape fiber, 400... Optical connector.

Claims (1)

[Claims] 1) GI optical fibers having a predetermined length and diameter are arranged in parallel and facing each other on both sides of a groove of a predetermined width provided on a substrate, and the optical axes of the opposing GI optical fibers are aligned with each other. 1. An integrated optical fiber functional component characterized in that a spot size conversion type coupling system is obtained between the opposing GI optical fibers via a beam waist by matching the GI optical fibers. 2) The pair of GI optical fibers facing each other is an optical fiber holding portion formed by straddling one continuous GI optical fiber on both sides of the groove before the groove of the predetermined width is provided. The integrated optical fiber function according to claim 1, characterized in that the integrated optical fiber function is formed to the predetermined length by being arranged and fixed in the groove and being removed along the groove when the groove is formed on the substrate. parts.