JPH02110407A - Optical fiber coupler - Google Patents

Abstract

PURPOSE:To reduce the dispersion of mutual optical characteristics for the respective pairs of optical fiber couplers and to miniaturize the optical fiber coupler by burying plural optical fiber in a parallel condition, fixing the fiber, grinding one part of each optical fiber and joining the fiber so that respective grinding surface can be overlapped. CONSTITUTION:Plural optical fiber 14 is buried and fixed in the parallel condition while brought into contact with side surfaces mutually into a groove 13 of a substrate 12 with groove. Then, a pair of substrates 16, for which one part of each optical fiber 14 is ground up to the near part of a core 14 and grinding surfaces 15 are formed, are joined so that the respective grinding surfaces 15 can be overlapped. Thus, the plural types of optical couple operation can be executed by one optical fiber coupler 11 and the dispersion of the optical characteristic can be reduced. Then, the optical fiber coupler to be needed for the plural types of the optical couple operation can be miniaturized.

Description

Detailed Description of the Invention "Field of Industrial Application" This invention relates to an optical fiber coupler used for branching or merging light within an optical fiber into multiple fibers in optical fiber sensors, optical communication equipment, etc. It is related to.

"Prior Art" FIG. 9 is a diagram showing an example of a conventional optical fiber coupler, and reference numeral 1 indicates the optical fiber coupler.

This optical fiber coupler l consists of a pair of substrates 6, in which a part of the optical fiber 2 is embedded in a groove 4 of a grooved substrate 3, and the part is polished to the vicinity of the core to form a polished surface 5. are joined together so that their respective polished surfaces 5 overlap.

In the optical fiber coupler I constructed in this manner, transmitted light is branched or merged at the coupling portion 7 where each polished surface 5 contacts.

By the way, in optical fiber communications and optical fiber sensors, a plurality of optical fiber couplers l as described above may be used.

In such a case, in order to utilize space effectively, it is necessary to accommodate a plurality of optical fiber couplers 1 one on top of the other.

``Problem to be solved by the inventionMJ However, in the conventional optical fiber coupler, even if the dimensions of the main body are small, 5 s + mX 5 aua
Since the size is approximately 20 mm, if a desired number of them are stacked one on top of the other, the overall size will become even larger, posing a problem that a large storage space will be required.

For example, when trying to fabricate four pairs of optical fiber couplers as shown in Figure 1O, the overall dimensions are 20 m in length.
m, width 20mm, and height 511m.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an optical fiber coupler that has the functions of a plurality of optical fiber couplers and requires a small accommodation space.

"Means for Solving the Problems" As a means for achieving the above object, the present invention embeds and fixes a plurality of optical fibers in parallel in a groove of a grooved substrate with their side surfaces in contact with each other, and An optical fiber coupler was constructed by bonding a pair of substrates formed by polishing a portion of a fiber to the vicinity of the core to form a polished surface so that the respective polished surfaces overlapped.

"Function" By configuring the optical fiber coupler as described above, a plurality of optical fibers are buried and fixed in parallel in the groove with their sides touching each other, so the parallelism between the axes of each optical fiber is , very good.

Since the outer diameter of the optical fiber can be controlled to 0.5 μm or less with respect to the base bond, for example, even if four pairs of optical fiber couplers are manufactured, the parallelism between the optical fiber axes will be a few μm.
It can be kept below m. Furthermore, by using an optical fiber with an outer diameter accuracy of 0.1 μm or less, this parallelism can be further improved. As a result, variations in the optical properties of the six pairs of optical fiber couplers are greatly reduced.

Furthermore, a single optical fiber coupler can perform a plurality of optical coupling operations, and the optical fiber coupler required to perform a plurality of optical coupling operations can be miniaturized.

"Embodiment" FIGS. 1 and 2 are diagrams showing an embodiment of the present invention, and reference numeral 11 indicates an optical fiber coupler.

This optical fiber coupler 11 has a plurality of optical fibers 14 embedded and fixed in parallel in a groove 13 of a grooved substrate 12 with their side surfaces in contact with each other, and some of these optical fibers 14 are The polished surface 15 is polished to the vicinity of the core 14a.
It is constructed by joining a pair of substrates 16 formed by forming a substrate 16 such that their respective polished surfaces 15 overlap. The two optical fibers 14 whose respective polished surfaces 15 are in contact with each other are
The optical fiber coupler 11 is configured to include a plurality of pairs of two optical fibers 14 capable of coupling light. ing.

As the optical fiber 14, quartz-based or multicomponent-based single-mode optical fibers, multi-mode optical fibers, etc. used in normal optical communications are preferably used, and polarization-maintaining optical fibers may also be used. can.

As the material for the grooved substrate 12, quartz or metal is preferably used. Further, the grooves 13 of the grooved substrate 12 are formed in an arcuate shape with a shallow center and deep ends. A plurality of optical fibers 14 within this groove 13 are embedded and fixed with an adhesive 18.

This optical fiber coupler 11 connects two optical fibers 14 with their polished surfaces 15 in contact with each other ff117.
Since it is configured with multiple pairs of couplers each consisting of two optical fibers 14, it is possible to perform multiple optical coupling operations at the same time. can.

Next, an example of a method for manufacturing the optical fiber coupler 11 will be described. To create this optical fiber coupler 11, first, as shown in FIGS. 3 and 4, it is shaped like a colored column, and one side of the column has an arc-shaped groove 1 that is shallow in the center and deep in both ends.
A grooved substrate 12 on which 3 is formed is prepared. Note that it is desirable to form expanded portions I9 at both ends of the groove 13 by expanding the groove 13 so that the end portions of the coating of the optical fiber 14 can be inserted therein.

Next, the grooves of this grooved board 12! 3, a plurality of optical fibers 14 from which a predetermined length of a part of the coating 20 has been removed are arranged in a line, and an adhesive 18 is injected into the groove 13 and solidified. As shown in FIG. 6, a plurality of optical fibers 14 are fixed to the grooved substrate 12. At this time, each optical fiber I4 is such that the bare optical fiber wire exposed by removing the coating 20 is inserted into the groove 13 as shown in FIGS. 5 and 6, and the end portion 21 of the coating 20 is inserted into the groove I3. It is desirable that the device be fixed in a state inserted into the expansion portion 19 of the device. Moreover, each optical fiber I4 is fixed in parallel in a contact state.

Next, a grooved substrate with a plurality of optical fibers 14 embedded and fixed!
2, the surface on the groove 13 side is polished. This polishing process
A part of the optical fiber 14 buried and fixed in the core 14a
The area should be exposed to the vicinity. By this polishing, the seventh
As shown in FIG. 8 and FIG. 8, a plurality of end fibers 14, each having a polished surface 15 polished to a portion near the core 14a, are buried and fixed in parallel in the groove 13 of the grooved substrate 12. A substrate 16 is obtained.

Next, the two substrates 16 produced as described above are joined using an adhesive or the like, with the polished surfaces 15 of the paired optical fibers 14 in contact with each other.

By each of the above operations, the optical fiber coupler shown in Figs. 1 and 2 can be created! ! is created.

The optical fiber coupler 11 according to this example has a plurality of optical fibers 14 embedded and fixed in parallel in contact with each other in the groove 13 of a grooved substrate 12, and a part of each optical fiber 14 is placed in the vicinity of the core 14a. A pair of substrates formed by polishing to form a polished surface 15! 6 are bonded together so that their respective polished surfaces 15 overlap, so one optical fiber coupler can stably perform multiple optical coupling operations, and the optical fiber coupler necessary for performing multiple optical coupling operations can be downsized.

Furthermore, since a plurality of optical fibers 14 are embedded and fixed in parallel in the groove 13, the parallelism between the tip fibers 14 is good, and the yield when creating an optical fiber coupler by overlapping them after polishing is improved. Can be done.

Note that the optical fiber 1 in the optical fiber coupler 11
The number 4 means that the number of optical fibers 14 on each board 16 is two or more, and each board to be bonded! 6 optical fiber/14
There is no particular limitation as long as the number of lines is the same.

(Manufacturing Example) An optical fiber coupler having the same structure as that shown in FIG. 1 was prepared using a single mode optical fiber for a wavelength of 1.3 μm with a core diameter of 8 μm, a fiber diameter of 125±0.3 μm, and a coating diameter of 400 μm.

The grooved substrate has the same configuration as that shown in FIGS. 3 and 4, and its dimensions are 20+u+ in length and 5III1 in width.
11 A quartz substrate with a height of 2.5 mm, a width of 0.6 mm,
A grooved substrate was used in which a groove with a width of 1.811111 mm was formed at the expanded portion of the groove crest end. This dimension is 174 in width of a conventional Kabra.

Then, the four optical fibers with approximately 15 mm of the coating removed from the optical fibers were lined up in the grooves of the grooved substrate, and then an epoxy adhesive was injected into the grooves and solidified. Four optical fibers were embedded and fixed in the grooves of the grooved substrate.

Next, the groove side surface of the grooved substrate to which the optical fiber is fixed is polished and removed to the extent that the area near the core of the optical fiber is exposed.
A substrate having the same structure as that shown in FIGS. 7 and 8 was obtained.

Next, the two substrates prepared as described above were stacked so that their respective polished surfaces were in contact with each other, and both substrates were bonded together using an epoxy adhesive. Through the above operations, an optical fiber coupler having the same structure as that shown in FIGS. 1 and 2 was obtained.

As a result of investigating the optical coupling characteristics of the optical fiber couplers obtained in this way, it was found that a pair of couplers with their respective polished surfaces in contact is different from a conventional optical fiber coupler configured with two optical fibers. Furthermore, the variation in the coupling degree of the four pairs of couplers was within ±2%, and the variation in excess loss was within ±0.1 dB, indicating almost uniform optical coupling performance.

"Effects of the Invention" As explained above, the optical fiber coupler according to the present invention embeds and fixes a plurality of optical fibers in parallel in a groove of a grooved substrate with their side surfaces in contact with each other, and A pair of substrates are formed by polishing a portion of the substrate to the vicinity of the core to form a polished surface, and are bonded together so that the polished surfaces of each substrate overlap, making it possible to perform multiple optical coupling operations with one optical fiber coupler. , variations in optical properties are reduced, and the optical fiber coupler required to perform multiple optical coupling operations can be downsized.

In addition, since a plurality of optical fibers are buried and fixed in the groove in parallel, the parallelism of the optical fibers is good, and the yield when creating an optical fiber coupler by stacking them after polishing can be improved.

[Brief explanation of the drawing]

1 and 2 are diagrams showing one embodiment of the present invention, in which FIG. 1 is a perspective view of an optical fiber coupler, and FIG. 2 is a perspective view of an optical fiber coupler.
3 to 9 are diagrams for explaining an example of the manufacturing method of the optical fiber coupler shown in FIG. 1, and FIG. 3 is a side view of the grooved substrate; Fig. 4 is a front view of the same, Fig. 5 is a side view of a grooved substrate with an optical fiber embedded in the groove, Fig. 6 is a sectional view taken along line B-B of Fig. 5, and Fig. 7 is a side view of the substrate. , FIG. 8 is a sectional view of the same, FIG. 9 is a side sectional view showing an example of a conventional optical fiber coupler, and FIG. 10 is a diagram showing the arrangement of the optical fiber couplers shown in FIG. FIG. 11... Optical fiber coupler, 12... Grooved board, 1
3... Groove, 14... Optical fiber, 14a... Core, 15... Polished surface, 16... Substrate.

Claims (1)

[Claims] A pair of optical fibers embedded and fixed in parallel in a groove of a grooved substrate with their sides touching each other, and a portion of each optical fiber is polished to the vicinity of the core to form a polished surface. An optical fiber coupler characterized in that it is made by joining two substrates such that their polished surfaces overlap.