Optical fiber connector and method of manufacturing the same

Abstract: To obtain an optical fiber connector for splicing a plurality of optical fibers integrally, V-groove substrates (1-1 ∼ 1-5) each comprising V-grooves (2) for receiving the optical fibers and positioning standard surfaces (5-1 ∼ 5-5) arranged in parallel with the V-groove direction are stacked on each other on the basis of the positioning standard surfaces (5-1 ∼ 5-5). The optical fibers are located accurately and compactly.

Description: The present invention relates to an optical fiber connector containing a plurality of optical fibers integrally, and also relates to a method of manufacturing the optical fiber connector mentioned above. As an optical fiber connector for splicing a plurality of optical fibers integrally, there is known, as shown in Fig. 4, an optical fiber connector 21 comprising a V-groove substrate 22 having a number of V-grooves 23 on which a number of optical fibers 24 are set respectively, and a cap plate 25 for pressing the optical fibers 24 from an upper side. In the optical fiber connectors 21 mentioned above, if the optical fiber connectors 21 each having the construction shown in Fig 4 are stacked with each other so as to increase the number of the optical fiber to be spliced, there is a drawback such that the optical fibers 24 arranged on upper and lower optical fiber connectors 21 are not positioned accurately. Moreover, there are drawbacks such as that a dimension of the optical fiber connector 21 becomes large, the number of members to be used for the optical fiber connector 21 becomes larger, and a working surface is not used effectively. US-A-4 046 454 and US-A-4 865 413 show similar arrangements. Further, one example of an optical fiber connector for splicing more number of the optical fibers integrally is shown as "Ultra high density single-mode 50-fiber connectors" in DENSI-TSUHIN-JY O H O -GAKKAI, 70th commemorative meeting, summary No 1999, page 9-82, 1987. Fig. 5 is a schematic view showing one embodiment of the optical fiber connector mentioned above. As shown in Fig. 5, an optical fiber connector 31 for splicing 50 optical fibers integrally is manufactured by stacking five optical fiber tapes each having ten optical fibers 32 in line in an accurate manner through resin members by means of a resin injection method and so on. In the optical fiber connector 31, as is the same as the optical fiber connector 21, a positional relation between ten optical fibers 32 arranged in line is accurate since the optical fiber tape is used, but the optical fibers 32 arranged upper and lower optical fiber tapes are not positioned accurately. As a result, when a plurality of optical fibers are spliced by using the optical fiber connectors mentioned above, the optical fibers are not spliced accurately and a light transmitting loss becomes larger, so that signals transmitting through the optical fibers are reduced in the optical fiber connectors. It is an object of the present invention to reduce or eliminate the drawbacks mentioned above, and to provide an optical fiber connector and a method of manufacturing the optical fiber connector mentioned above, which can splice a plurality of optical fibers integrally in an accurate and compact manner. According to the invention, there is provided an optical fiber connector as set out in claim 1. According to the invention, there is also provided a method of manufacturing an optical fiber connector as set out in claim 4. In the construction of the invention, it is not necessary to use all the cap members except for the uppermost cap member when stacking the V-groove substrates. Therefore, the optical fiber connector according to the invention can reduce the number of members to be used and be compact in size. Moreover, in a preferred embodiment, V-grooves of the V-groove substrates for setting a plurality of optical fibers, positioning reference surfaces utilized when stacking the V-groove substrates, and guide-grooves for setting guide pins are formed by using the same working standard surfaces. Moreover, also in the preferred embodiment, the optical fiber connector for splicing a plurality of optical fibers is manufactured by stacking the V-groove substrates by using the same positioning reference surfaces. Therefore, the optical fibers arranged upper and lower V-groove substrates are positioned accurately as well as the optical fibers arranged in line. Fig. 1 is a schematic view showing one embodiment of an optical fiber connector according to the invention; Fig. 2 is a schematic view illustrating an another embodiment of an uppermost V-groove substrate; Figs. 3a to 3c are schematic views depicting respective steps of a method of manufacturing the optical fiber connector according to the invention; Fig. 4 is a schematic view showing one embodiment of a know V-groove substrate; and Fig. 5 is a schematic view illustrating one embodiment of a known optical fiber connector. Fig. 1 is a perspective view showing one embodiment of an optical fiber connector for splicing a plurality of optical fibers according to the invention. In this embodiment, each V-groove substrate 1-1∼1-5 holds eight optical fibers in line respectively. That is to say, eight V-grooves 2 for setting optical fibers are formed equidistantly and at the same positions on respective V-groove substrates 1-1∼1-5. Moreover, two grooves 3 for setting guide pins are formed at the same positions on the lowermost V-groove substrate 1-1 and the uppermost V-groove substrate 1-5. In case of stacking the V-groove substrates 1-1∼1-5, bottom outer surfaces of the V-groove substrate 1-2∼1-5 except for the V-groove substrate 1-1 press the optical fibers in the V-grooves 2. Further, working reference surfaces 4-1∼4-5 are arranged on one side surfaces of respective V-groove substrates 1-1∼1-5, and positioning reference surfaces 5-1∼5-5, each having L-shape cross section and defined by a vertical surface of the L-shape cross section, are arranged on the other side surfaces of respective V-groove substrates 1-1∼1-5. Moreover, a cap plate 6 is arranged on the uppermost V-groove substrate 1-5 so as to press the optical fibers in the V-grooves 2 of the uppermost V-groove substrate 1-5. Connections after stacking operations between respective V-groove substrates 1-1∼1-5 and between the V-groove substrate 1-5 and the cap plate 6 are performed by using adhesion agents such as resin. It should be noted that the L-shape positioning reference surfaces 5-1∼5-5 may be cut out to obtain a plain side surface. Fig. 2 is a schematic view showing another embodiment of the uppermost V-groove substrate utilizing the cap plate 6. In the embodiment shown in Fig. 2, only the uppermost V-groove substrate 1-5 and the cap plate 6 are shown. As shown in Fig. 2, the cap plate 6 is formed by an optical fiber press portion 7 arranged corresponding to the V-grooves 2 and a guide pin press portion 9 separately formed with the optical fiber press portion 7 and having grooves arranged corresponding to the grooves 3. Therefore, since the optical fibers and the guide pins are separately fixed by using the optical fiber press portion 7 and the guide pin press portion 9, it is possible to realize a more stable optical fiber connector than the connector shown in Fig. 1. Figs. 3a∼3c are schematic views showing respective steps of a method of manufacturing the optical fiber connector according to the invention. At first, as shown in Fig. 3a, five ceramic substrates 10-1∼10-5 each having the same dimension are set in line to a right-angled support member 11 on the basis of the working standard surfaces 4-1∼4-5 arranged parallel to a V-groove direction. Then, as shown in Fig. 3b, eight V-grooves 2 are formed on surfaces of respective ceramic substrates 10-1∼10-5, and the positioning reference surfaces 5-1∼5-5 each having an L-shape cross section are formed on the other side surfaces with respect to the working standard surfaces 4-1∼4-5, by using a grinding machine not shown to obtain the V-groove substrates 1-1∼1-5. Further, as shown in Fig. 3c, only the lowermost V-groove substrate 1-1 and the uppermost V-groove substrate 1-5 are set to the right-angled support member 11, and then the grooves 3 for holding the guide pins are formed on the V-groove substrates 1-1 and 1-5. Then, the optical fibers are set in the V-grooves 2 of respective V-groove substrates 1-1∼1-5, the V-groove substrates 1-1∼1-5 are stacked by using a comb-shape support member not shown on the basis of the positioning reference surfaces 5-1∼5-5. Finally, the cap plate 6 is arranged on the uppermost V-groove substrate 1-5 to obtain the optical fiber connector according to the invention. In this case, even if the dimensions of the ceramic substrates 10-1∼10-5 are different a little with each other, the positional relations between the V-grooves 2 and the positioning reference surfaces 5-1∼5-5 become always accurate, since they are worked at the same time by using the right-angled support member 11. Therefore, the optical fibers fixed in the V-grooves 2 of the V-groove substrates 1-1∼1-5 can be arranged in an accurate manner, if the V-groove substrates 1-1∼1-5 are stacked on the basis of the positioning reference surfaces 5-1∼1-5 are stacked on the basis of the positioning reference surfaces 5-1∼5-5. Further, in the present invention, the reason for using the positional reference surfaces 5-1∼5-5 is as follows. That is to say, if the V-groove substrates are stacked on the basis of the working reference surfaces 4-1∼4-5, the positional relations between the V-grooves 2 and the working reference surfaces 4-1∼4-5 do not become accurate, since they are varied due to a parallelity of the right-angled support member 11, a positional relation between the right-angled support member 11 and the grinding machine, and a dust existence between the ceramic substrates 10-1∼10-5 and the right angled support member 11. The present invention is not limited to the embodiments mentioned above, but various modifications can be possible. For example, in the preferred embodiments mentioned above, the cap member 6 comprising the optical fiber press portion 7 and the guide pin press portion 9 is arranged only on the uppermost V-groove substrate 1-5, but it is possible to form the same construction on the bottom outer surface of the V-groove substrate 1-2 which functions to press the lowermost V-groove substrate 1-1 so as to fasten the optical fibers and the guide pins in an accurate manner. Moreover, in the embodiment mentioned above, the positioning reference surfaces have the L-shape cross section, but it is possible to use other cut-out surfaces as the positioning standard surfaces. As clearly understood from the above, according to the invention, since it is not necessary to use all the cap members except for the uppermost cap member, the optical fiber connector according to the invention can reduce the number of members to be used and can make compact in size. Moreover, in the preferred embodiments, since the V-grooves of the V-groove substrates, the positioning reference surfaces and the guide-grooves are formed by using the same working reference surfaces, and since the optical fiber connector is manufactured by stacking the V-groove substrates by using the same positioning reference surfaces, the optical fibers arranged upper and lower V-groove substrates are positioned accurately as well as the optical fibers arranged in line.

Claims: An optical fiber connector containing a plurality of optical fibers, having a plurality of substrates (1-1 to 1-5) each substrate having a plurality of parallel V-grooves (2) in a main surface receiving the optical fibers therein, the substrates being stacked one on top of another so that optical fibers in the V-grooves of one substrate are pressed by the lower surface of the next higher substrate in the stack, characterised in that said V-groove substrates each have a cut-out portion providing positioning reference surfaces (5-1 to 5-5) and extending parallel to the V-grooves to enable accurate location of each substrate and its grooves relative to each other substrate whilst the substrates are in said stack. An optical fiber connector according to claim 1 wherein said substrates also have, guide grooves (3) for receiving location guide pins. An optical fiber connector according to claim 1 and claim 2 wherein said V-groove substrates are ceramic. A method of manufacturing an optical fiber connector containing a plurality of optical fibers, comprising the steps of, forming parallel V-grooves (5-1 to 5-5) for the optical fibers in a main surface of each of a plurality of ceramic substrates (1-1 to 5-5), forming a cut-out positioning reference surface in each said substrate (5-1 to 5-5) extending parallel to said V-grooves thereon, and stacking said substrates having V-grooves, on which optical fibers are set, with mutual relative location of the V-grooves on the stacked substrates being achieved by use of said positioning reference surfaces. A method of manufacturing an optical fiber connector according to claim 4, further comprising a step of forming additional guide grooves (3) for location guide pins in a plurality of said substrates. A method of manufacturing an optical fiber connector according to claim 4 or claim 5, wherein said V-grooves (3) and position reference surfaces (5-1 to 5-5) are formed by grinding said substrates. A method of manufacturing an optical fiber connector according to any one of claims 4 to 6, wherein said V-grooves and position reference surfaces parallel thereto are formed by cutting them while said substrates are located in a row against a common positioning surface of a jig (11).

Inventors: FUKUYAMA MASASHI, MAEKAWA KOICHIRO, OTA TAKASHI, FUKUYAMA, MASASHI, MAEKAWA, KOICHIRO, OTA, TAKASHI
Applicants: NGK INSULATORS LTD, NIPPON TELEGRAPH & TELEPHONE, NGK INSULATORS, LTD., NIPPON TELEGRAPH & TELEPHONE PUBLIC CORPORATION
Application year: 1993
Main classification: G02B6
IPC codes: G02B6