JPH06109951A - Production of optical transmission device - Google Patents

Abstract

PURPOSE:To simplify high-accuracy optical axis alignment in optical packaging and to couple optical waveguides and optical fibers with low loss without adjustment by taking reliability and productivity into consideration. CONSTITUTION:Circular metallic pads 16 and 18 formed on the end faces of an optical waveguide element 10 and a block 21 with thin guide for aligning the optical fibers are bonded by solder bumps 17 and the optical axes of the optical waveguides 12 and V-grooves 20 are aligned with high accuracy without adjustment. Then, a block 22 with optical fiber fixing guides is adhered to the block 21 with the thin guides for aligning the optical fibers without taking care for the alignment accuracy. The high-accuracy coupling in optical packaging is easily executed simply by butting the optical fibers 14 against each other along the guides of the V-grooves 20 in the final.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an optical transmission device, and particularly to connecting an optical waveguide element and an optical fiber terminal which constitute an optical communication module for modulating a light wave and switching an optical path in optical communication. The present invention relates to a method for manufacturing an optical transmission device.

[0002]

2. Description of the Related Art Practical application of optical communication systems has advanced, and development of advanced systems having large capacity and multiple functions has been advanced. New functions such as a switching function of an optical transmission line network, a high-speed connection between terminals in an optical data bus, and a switching function are required, and the need for an optical communication network that enables them is increasing.

In the realization of optical transmission having such a large capacity and wide band, for example, an optical switch currently in practical use mechanically moves a prism, a mirror, a fiber, etc., and is low speed. However, there are drawbacks such as insufficient reliability, large shape, and unsuitable for matrix formation. As one example that is being developed as a means to solve this, there is a waveguide type optical switch that uses an optical waveguide installed on a substrate, and has features such as high speed, multi-element integration and high reliability. . In particular, a material using a ferroelectric material such as LiNbo ₃ crystal has features such as high efficiency because it has small light absorption and low loss and has a large electro-optical effect. It is expected to be applied to fields such as exchange.

In the connection of such a waveguide type optical device and an optical transmission network, it is required that the optical fiber is stable with respect to environmental changes such as temperature changes and has a small optical loss. High precision (1 to 10 μm) alignment and fixing are required, and the simplest configuration is realized by abutting the end face of the optical waveguide and the end face of the optical fiber.

FIG. 3 shows a perspective view of an example of a conventional optical transmission apparatus having a combination structure of a waveguide type optical device and an optical fiber terminal. In FIG. 3A, the optical waveguide 112 is formed on the substrate 111, and the optical fibers 114 arrayed in the optical fiber terminal 113 are brought into abutment with the optical waveguide 112 by adjusting the optical axis, and the UV is maintained while maintaining that state. The optical fiber terminal 113 is fixed to the substrate 111 with an adhesive 115 such as a cured resin. Regarding the fixing method, in addition to adhesive, solder welding,
There is laser welding.

Further, FIG. 3B shows an optical waveguide device 110.
And metal pads 116 and 118 each having a size of several tens to several hundreds of μm on each end face of the optical fiber terminal 113, and solder bumps are formed on the metal pads 116.
Through this bump, the end face coupling between the optical waveguide device 110 and the optical fiber terminal 113 can be adjusted without any adjustment and the optical axis can be accurately aligned.

[0007]

In the above-described conventional method of manufacturing an optical transmission device, it is necessary to align and fix the optical waveguide element and the optical fiber terminal with high accuracy. However, the optical axis adjusting and fixing methods of the conventional example are not suitable for those requiring long-term stability and have poor productivity, because the positional deviation during fixing and the change over time are large. Even when laser welding is used, the problem of requiring highly accurate optical axis adjustment cannot be solved. Further, in the coupling method using bumps, both the optical waveguide element and the optical fiber terminal are required to have a certain size, and their weight cannot be ignored. In particular, since the optical fiber is already connected to the optical fiber terminal, the self-alignment effect due to the solder bump cannot be fully utilized. In the future, it is expected that the optical device module will be required to have higher accuracy and lower optical loss, and it is necessary to simplify the optical axis alignment and to improve the accuracy in optical mounting.

[0008]

A method for manufacturing an optical transmission device according to the present invention is directed to an end face of an optical waveguide element having an optical waveguide formed on a substrate surface and an end face of an optical fiber terminal on which optical fibers are arranged. In a light transmission device in which circular metal pads that form a circle are provided and the metal pads are bonded to each other via bumps, the optical fiber terminal includes a block with a thin guide for optical fiber alignment and a block with a guide for fixing the optical fiber. And a step of connecting the optical waveguide element and the block with the thin guide for optical fiber alignment with high precision using bumps, and the block with the guide for fixing the optical fiber is aligned with the optical fiber. And a step of arranging the optical fibers after being attached to a block with a thin guide.

[0009]

According to the method of manufacturing the optical transmission device of the present invention, the circular metal pads formed on the end faces of the optical waveguide element and the block with the optical fiber alignment thin guide forming the optical fiber terminal are joined by solder bumps. By the self-alignment effect of the molten solder, the optical axis alignment between the optical waveguide element and the thin guide block for optical fiber alignment can be realized with high accuracy without adjustment. This is because the self-alignment effect is not hindered because the optical fiber is not connected and the optical fiber terminal is a light weight thin block having a fraction of one to one tenth of the original. After the high-accuracy alignment (automatic adjustment and fixation) in this manner, the optical fiber fixing guide block for arranging and fixing the optical fibers can be bonded with almost no concern about the alignment accuracy. Therefore, highly accurate coupling in optical mounting is easily realized.

[0010]

The present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view for explaining an embodiment of the present invention, which shows a connection method for connecting an optical waveguide element and an optical fiber terminal composed of two kinds of blocks with guides at an end face via solder bumps. Show.

Circular metal pads 16 and 18 that form a pair are formed on the joint surfaces of the optical waveguide element 10 and the block 21 with a thin guide for aligning the optical fibers, and the solder bumps 17 are used for bonding without adjustment. High precision optical axis alignment can be realized.

On the end face of the optical waveguide device 10 having the optical waveguide 12 formed on the surface of the substrate 11, a circular metal pad 16 having a diameter of several tens of μm and a solder bump 17 are formed. The metal material of the metal pad 16 differs depending on the material of the solder bump 17 used, but is preferably Cr-Ni for PbSn solder and Cr-Au for AuSn solder. The height of the solder bump is preferably several tens to several hundreds μm. A circular metal pad 18 similar to that of the optical waveguide device 10 is also formed on the end face of the block 21 with the thin guide for optical fiber alignment. The positional relationship between the V-grooves 20 for arranging the optical fibers 14 and the metal pads 18 matches that of the optical waveguide 1 and the metal pads 16.

First, as shown in FIG. 1A, a block 21 with a thin guide for optical fiber alignment is temporarily connected to the optical waveguide device 10. Since the alignment at this time may be such that a part of the metal pad 18 on the end face of the block 21 with the thin guide for optical fiber alignment comes into contact with the solder bumps 17, high-precision alignment conventionally required can be achieved. It becomes unnecessary.

Here, when the solder bumps 17 are melted, the self-alignment effect due to the surface tension of the molten solder 19 as shown in FIG. 1 (B) causes the optical waveguide 12 and the optical fiber as shown in FIG. 1 (C). High-precision alignment with 14 is automatically performed and can be fixed at the same time.

Next, the block 22 with a gad for fixing the optical fiber is connected to the block 21 with a thin guide for positioning the optical fiber by an adhesive 15. Since the optical axis alignment between the waveguide 12 and the G groove 20 is already fixed with high accuracy, the bonding here may be performed with accuracy of about several tens to several hundreds of μm, and conventionally required adjustment accuracy of the μm order. Can be significantly eased. Finally, as shown in FIG. 1 (D), the optical fiber 14 is inserted along the V groove 20 and fixed by being attached to the end face of the optical waveguide element 10 to achieve high-precision coupling without adjustment of optical mounting. realizable.

FIG. 2 is a perspective view of an optical fiber terminal including an optical waveguide element and two types of blocks with guides according to an embodiment of the present invention. The bonding method using solder bumps enables highly accurate optical axis alignment without adjustment.

[0017]

As described above, according to the present invention, a circular metal pad that makes a pair with an end face of an optical waveguide element having an optical waveguide formed on a substrate surface and an end face of an optical fiber terminal on which optical fibers are arranged. In the optical transmission device in which the metal pads are bonded to each other through the bumps, the optical fiber terminal is composed of a block with a thin guide for optical fiber alignment and a block with a guide for fixing the optical fiber. And the block with the thin guide for optical fiber alignment are connected with high precision using bumps, and the block with the guide for fixing the optical fiber is attached to the block with the thin guide for aligning the optical fiber, and then the optical fibers are arranged. By doing so, highly accurate alignment of the optical axis in optical mounting can be achieved, and the optical waveguide and the optical fiber can be easily coupled with low loss. . Further, it is practical because it has high reliability against temperature changes and the like and has excellent productivity.

[Brief description of drawings]

FIG. 1 is a cross-sectional view for explaining a manufacturing process according to an embodiment of the present invention.

FIG. 2 is a perspective view of an optical waveguide device and an optical fiber terminal of this embodiment.

FIG. 3 is a perspective view of an example of a conventional optical transmission device.

[Explanation of symbols]

10 Optical Waveguide Element 11 Substrate 12 Optical Waveguide 13 Optical Fiber Terminal 14 Optical Fiber 15 Adhesive 16, 18 Circular Metal Pad 17 Solder Bump 19 Molten Solder 20 V Groove 21 Block with Optical Fiber Alignment Thin Guide 22 Optical Fiber Fixing Block with guide

Claims (1)

[Claims] 1. A circular metal pad that forms a pair with an end face of an optical waveguide element in which an optical waveguide is formed on a substrate surface and an end face of an optical fiber terminal on which optical fibers are arranged is provided, and the metal pads are connected to each other. In the optical transmission device adhered via a bump, the optical fiber terminal is composed of a block with an optical fiber alignment thin guide and a block with an optical fiber fixing guide, and the optical waveguide element and the optical fiber alignment For connecting the block with the thin guide for use with bumps with high accuracy, and arranging the optical fibers after the block with the guide for fixing the optical fiber is attached to the block with the thin guide for aligning the optical fiber And a step of manufacturing the optical transmission device.