JPH09281356A - Waveguide type fiber connector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a waveguide type connector which connects high-refractive index optical waveguides of semiconductors, etc., and quartz optical fibers with low loss and embodies connectability with decreased variations even if the optical circuits to be connected are plural. SOLUTION: The waveguide type connector 5 formed by fusion splicing the quartz optical fibers 4a, 4b, 4c, 4d to one end of a connector chip 3 formed with the quartz optical waveguides 2a, 2b, 2c, 2d changing continuously in the diameters and shapes of mode fields 20a, 20b, 20c, 20d on a quartz substrate 1 and forming an end face at the other end is used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a connector, and more particularly to a waveguide type fiber connector for connecting a silica optical fiber to the input / output portion of an optical element having an optical circuit formed of a material other than silica as a substrate. It is a thing.

[0002]

2. Description of the Related Art Among optical devices using materials other than quartz, especially semiconductor materials, photodiodes, laser diodes, etc. have already become widespread by themselves. In addition, development and commercialization of optical modulators, optical switches, optical amplifiers, etc. that use an optical waveguide mechanism are rapidly progressing. In particular, optical modulators and switches are capable of arbitrarily controlling and processing optical signals and processing them spatially. Therefore, early commercialization of various optical sensors such as optical gyros as key devices in optical communication networks is strongly desired. There is.

In a semiconductor optical switch, for example, a 4 × 4 optical switch has been developed in which an InGaAsP-based mixed crystal optical waveguide is formed on an InP substrate and a local change in the refractive index due to carrier injection is utilized to develop a direct optical switching. The application to high-speed and high-reliability optical switching is being considered.

In order to widely apply an optical element made of a semiconductor material, it is indispensable to connect it to a silica optical fiber which is a light transmission path. Generally, the refractive index of a semiconductor material is 3 to 3.5, which is much larger than 1.46 of a quartz material. Therefore, when the waveguide is set to a single mode, the wavelength of 1.5
When comparing the mode field diameters at 5 μm, the silica optical fiber is about 10 μm, and the InGaAsP optical waveguide is about 3 μm, which is a big difference. Reflection loss due to

When connecting an optical waveguide made of a semiconductor material to a silica-based optical fiber, as shown in FIG. 5, the optical fiber 22 from which the optical fiber jacket 21 is peeled off is processed into a spherical shape to obtain a lens effect. The held spherical fiber is used. The tip spherical fiber is brought close to the end face of the optical waveguide made of a semiconductor material to couple light. As a method of processing the tip into a spherical shape, a polishing method, an etching method, or the like can be appropriately used.

FIG. 6 shows a case where a plurality of optical fibers are simultaneously connected to a plurality of input / output terminals. An optical fiber 25a whose optical fiber jacket 24 is peeled off and the tip is processed into a spherical shape
25d are arranged and arranged on a jig 26 in which the surface of a silicon or quartz substrate is V-grooved, and this fiber array is brought close to the end face of the waveguide of the semiconductor to couple a plurality of lights at the same time.

[0007]

The above-mentioned prior art has the following problems. In the method shown in FIG. 5 in which the tip of the optical fiber is processed into a spherical shape and coupled, there is a limit in the difference in refractive index and processing into a spherical shape, so the connection loss is extremely large at 4 to 6 dB per location. There was a problem. Further, since the tip spherical fiber has a tip of a glass cylinder with a diameter of 125 μm cut to a diameter of about 10 μm, it has a difficulty in handling such as being easily broken by contact or the like.

Further, in the method shown in FIG. 6 in which the fiber array is brought close to the end face of the semiconductor waveguide and a plurality of light beams are simultaneously coupled, the optical axes of the respective fibers and the semiconductor optical waveguide do not always match, There is a problem that the coupling loss varies. This loss variation is due to the V-groove processing of the surface of the Si or quartz substrate when manufacturing a jig.
This is due to processing variations.

Therefore, the present invention was devised to solve the above-mentioned problems, and is applied to an optical element in which an optical circuit is formed by using a material other than quartz as a substrate, especially at an input / output end of a semiconductor optical switch or the like. SUMMARY OF THE INVENTION It is an object of the present invention to provide a waveguide type fiber connector for easily connecting a silica optical fiber with low loss.

[0010]

According to the present invention, in order to achieve the above object, an optical waveguide is formed from a silica-based core formed on a quartz substrate and a silica-based cladding that embeds the core. A silica-based optical fiber was fused to one end of a silica-based optical waveguide element, and an end face of the optical waveguide was formed at the other end of the silica-based optical waveguide element.

Further, in the above-mentioned waveguide type fiber connector, a plurality of cores of the optical waveguide are provided, and the intervals between the cores are different between the fusion splicing side of the silica optical fiber and the end face forming side of the optical waveguide. A waveguide type fiber connector characterized by being formed as described above was used.

In the above waveguide type fiber connector, the mode field diameter and shape of the optical waveguide are formed so as to be different between the fusion splicing side of the silica optical fiber and the end face forming side of the optical waveguide. A waveguide type fiber connector characterized by

Further, in the above waveguide type fiber connector, a waveguide type fiber connector characterized in that a lens or a multilayer film is formed on an end face of the above optical waveguide is used.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION A first embodiment according to the present invention is shown in FIG. Mode field 20a on the quartz substrate 1,
The silica-based optical waveguides 2a, 2b, 2c and 2d are formed in which the diameters and shapes of 20b, 20c and 20d are continuously changed. The silica-based optical fibers 4a, 4b, 4c, and 4d are fusion-spliced to one end of the connector chip 3 thus formed, and the end face is formed at the other end of the connector chip 3 to produce the waveguide connector 5. ing. By the photolithographic technique, the silica-based optical waveguides 2a, 2b, 2c, 2d on the end face 9 of the waveguide connector 5 are formed with a pitch of 250 μm, and the silica-based optical fibers 4a, 4b, 4c, 4d are fusion-spliced. It is formed with a 1 mm pitch. Since the pitch is formed by the photolithographic technique, it can be set at an arbitrary interval.

FIG. 2 shows a waveguide type connector of the present invention 4 ×.
An example applied to a 4-semiconductor optical switch is shown. The waveguide connectors 5a and 5b are the same. The waveguide connectors 5a and 5b were butted against the input / output ends of the 4 × 4 semiconductor optical switch 7 and fixed on the mount 8. The waveguide of the semiconductor optical switch 7 has a width of 3 μm, and the semiconductor waveguide 6a,
6b, 6c and 6d are formed at a pitch of 250 μm. Semiconductor optical switch 7 and waveguide type connectors 5a and 5b
The connection loss was 3.2 to 4 dB per location, and good connection with little variation was obtained. The reason for the small variation is that the waveguides of the waveguide connectors 5a and 5b are formed by the photolithographic technique, and the core positional accuracy of ± 0.2 μm or less is easily achieved.

FIG. 3 shows a second embodiment of the present invention. A convex lens 10a, 10b, 10c, 10d is formed on an end face 9 of a waveguide type connector 5 similar to that shown in FIG. When this waveguide type connector 5 is applied to the above-mentioned 4 × 4 semiconductor optical switch 7 in the same manner as in FIG. 2, the connection loss between the semiconductor optical switch 7 and the waveguide type connector 5 is 1.3 per location. Good connection characteristics with a low loss of 1.5 dB and less variation were obtained.

FIG. 4 shows a third embodiment of the present invention 1. In the waveguide connector 12, only one silica optical fiber 4 is fusion-spliced. The mode field diameter on the optical fiber connection side is about 10 μm, and the end face 13 of the waveguide connector 12 is formed so that the mode field diameter is about 8 μm. Then, the multilayer filter 14 is formed on the end face 13. In FIG. 4, this waveguide type connector 12
Is applied to the 1.3 / 1.55 μm bidirectional optical transmission element 15.

In FIG. 4, 16 is a light receiving element, 17 is a light emitting element, 18 is transmission signal light, and 19 is reception signal light. The connection loss between the 1.3 / 1.55 μm bidirectional optical transmission element 15 and the waveguide connector 12 was 3.5 dB, and the isolation was 50 dB, which was a good connection characteristic.

[0019]

A quartz-based core formed on a quartz substrate,
A silica-based optical waveguide element formed of a silica-based clad that fills the core is fused with a silica-based optical fiber at one end, and the end face of the silica-based optical waveguide is formed at the other end. A waveguide-type fiber connector is used, and further, in the above-mentioned waveguide-type fiber connector, a plurality of cores of the silica-based optical waveguide are provided, and the intervals between the cores are the optical fiber fusion splicing side and the optical waveguide end face. A waveguide-type fiber connector characterized by being formed differently on the formation side is used, and in the above-mentioned waveguide-type fiber connector, the mode field diameter and shape of the silica-based optical waveguide are Using a waveguide type fiber connector characterized in that the fusion splicing side and the optical waveguide end face formation side are formed differently, and the above waveguide In fiber connector, the following effects can be obtained by using a waveguide-type fiber connector, characterized in that the formation of the lens or multilayer film on the optical waveguide end face.

A low loss connection between a silica-based optical fiber and a high refractive index optical waveguide such as a semiconductor can be realized. In addition, even in a multi-core connection, good connection with less loss variation can be achieved. Furthermore, since a multilayer filter and various optical devices can be added to the end face of the waveguide connector, not only connection but also functions such as optical signal processing / processing can be provided, which is industrially useful. is there.

[Brief description of drawings]

FIG. 1 is a plan view showing a first embodiment of a waveguide connector according to the present invention.

FIG. 2 is a plan view showing a method of coupling a waveguide type connector and a semiconductor optical switch according to the present invention.

FIG. 3 is a plan view showing a second embodiment of the waveguide connector according to the present invention.

FIG. 4 is a plan view showing a third embodiment of the waveguide connector according to the present invention.

FIG. 5 is a plan view showing the outer appearance of a tip spherical fiber according to a conventional technique.

FIG. 6 is a plan view showing an outline of a tip spherical fiber array according to a conventional technique.

[Explanation of symbols]

1 Quartz substrate 2a, 2b, 2c, 2d Quartz optical waveguide 3 Connector chip 4, 4a, 4b, 4c, 4d Quartz optical fiber 5, 5a, 5b, 12 Waveguide connector 6a, 6b, 6c, 6d Semiconductor optical Waveguide 7 Semiconductor optical switch 8 Mount 9, 13 End surface 10a, 10b, 10c, 10d Convex lens 14 Multilayer film filter 15 Bidirectional optical transmission element 16 Light receiving element 17 Light emitting element 18 Transmission signal light 19 Reception signal light 20a, 20b, 20c, 20d , 23 Mode field

Claims (6)

[Claims] 1. A quartz-based core formed on a quartz substrate,
A silica optical fiber is fusion-spliced to one end of a silica optical waveguide element in which an optical waveguide is formed from a silica cladding clad to embed the core, and an end face of the optical waveguide is formed at the other end. A waveguide fiber connector. 2. The waveguide type fiber connector according to claim 1, wherein a plurality of cores of the optical waveguide are provided, and the cores are spaced from each other by a fusion splicing side of the silica optical fiber and an end face of the optical waveguide. A waveguide type fiber connector characterized in that it is formed differently on the side. 3. The waveguide type fiber connector according to claim 2, wherein the mode field diameter of the optical waveguide is different between the fusion splicing side of the silica optical fiber and the end face forming side of the optical waveguide. A waveguide type fiber connector characterized by the above. 4. The waveguide type fiber connector according to claim 3, wherein the mode field shape of the optical waveguide is formed so as to be different on the fusion splicing side of the silica optical fiber and the end face forming side of the optical waveguide. A waveguide type fiber connector characterized by the above. 5. The waveguide type fiber connector according to claim 4, wherein a lens is formed on an end face of the optical waveguide. 6. A waveguide type fiber connector according to claim 4, wherein a multilayer film filter is formed on an end face of the optical waveguide.