JPH02284104A - Structure for connecting waveguide type optical module and optical fiber - Google Patents

Abstract

PURPOSE:To eliminate the inconvenience which is heretofore encountered with the use of an adhesive agent and to improve reliability by fixing a waveguide type optical module and an optical fiber to 1st and 2nd pipe members respective ly made of metal and fixing the 1st pipe member and the 2nd pipe member to each other by a laser welding. CONSTITUTION:The waveguide type optical module 1 having an optical waveguide part 1a is so fixed into the 1st pipe member 2 made of metal as to expose the end face of the optical waveguide part 1a. The optical fiber 3 is so inserted and fixed into the 2nd pipe member 4 made of metal having a fine hole as to expose the end face thereof. The 1st pipe member 2 and the 2nd pipe member 4 are then fixed by the laser welding while the end face of the optical waveguide part 1a and the end face of the core 3a of the optical fiber 3 are disposed to face each other. The need for the adhesive agent in the juncture at the time of joining the waveguide type optical module 1 and the optical fiber 3 is eliminated in this way and the reliability to a temp. change, etc., is improved.

Description

[Detailed Description of the Invention] Summary Regarding a connection structure between a waveguide type optical module and an optical fiber, the purpose of the present invention is to provide a connection structure with high reliability against temperature changes, etc. The optical fiber is fixed in a first metal pipe member so that the end face of the wave portion is exposed, and the optical fiber is inserted and fixed into a second metal pipe member having a pore so that the end face is exposed. The first pipe member and the second pipe member are fixed by laser welding with the end face of the optical fiber facing the core end face of the optical fiber.

INDUSTRIAL APPLICATION FIELD The present invention relates to a connection structure between a waveguide type optical module such as a waveguide type optical modulator module and an optical fiber.

In order to construct an optical communication system, in addition to basic components such as a light source device, a light receiving device, and an optical transmission line, various optical modules such as an optical modulator and an optical switch are required. One type of optical module is a waveguide type. A waveguide type optical module is configured to form an optical waveguide with a higher refractive index on a waveguide substrate, and control the optical phase etc. while confining the optical beam within this optical waveguide. In addition to the advantages that it is easy to downsize due to its structure and can be mass-produced using brainer technology, etc., it also has the advantage of being able to effectively apply electric and magnetic fields and dramatically reducing power consumption. It has the advantage of being A specific example of a waveguide type optical module is an external modulator for a semiconductor laser that is constructed using a titanium-diffused lithium niobate waveguide type optical switch, and it is used in various places as a device that contributes to speeding up optical communication systems. There is a lot of research going on. When putting such waveguide type optical modules into practical use, optimization of the connection structure with optical fibers is being sought.

BACKGROUND OF THE INVENTION FIG. 8 is a diagram showing a conventional connection structure between a waveguide type optical module and an optical fiber. FIG. 5(a) is a perspective view showing this connection structure, and FIG. 2(b) is a longitudinal sectional view thereof. 102 is a waveguide substrate made of lithium niobate (L i N b Oz>, etc.; 104 is an optical waveguide formed by thermally diffusing Ti at a predetermined position on the surface of the waveguide substrate 1°2; 10
6 is a reinforcing plate bonded to the edge of the waveguide substrate 102 so that its end surface is on the same plane as the end surface of the waveguide substrate 102; 108 is an optical fiber to be optically coupled to the optical waveguide B 104;
1°8a is the core of the optical fiber 108. In this conventional example, the end face of the core 108a of the optical fiber is connected to the optical waveguide 10.
In order to make a mechanical connection between the waveguide type optical module and the optical fiber while facing the end face of the optical fiber 10,
8 is inserted and fixed into a ring 110 made of ruby or the like to increase the bonding area, and the ring 110 and the waveguide substrate 1 are
02 and the reinforcing plate 106 are bonded together using an optical adhesive.
A waveguide type optical module and an optical fiber are connected.

Problem to be Solved by the Invention In the conventional connection structure shown in FIG.
Although it is possible to make a relatively strong connection by increasing the bonding area by using a If significant temperature changes or repeated temperature changes in the usage environment, the connection may become incomplete.
In the worst case, it will lead to damage.

The present invention was created in view of these problems.
The purpose is to provide a connection structure that is highly reliable against temperature changes when using a waveguide type optical module.

Means for Solving the Problems The above-mentioned technical problems are solved by a connection structure between a waveguide type optical module and an optical fiber, the basic structure of which is shown in FIG.

In the connection structure between a waveguide type optical module and an optical fiber according to the present invention, as shown in FIG. fixed inside the first metal pipe member 2,
As shown in FIGS. 3A and 3B, the optical fiber 3 is inserted and fixed into a second metal pipe member 4 having a pore so that its end face is exposed, and as shown in FIGS. The first pipe member 2 and the second pipe member 4 are fixed by laser welding with the end face of the optical fiber 3 and the end face of the core 3a of the optical fiber 3 facing each other.

Function According to the configuration of the present invention, the waveguide type optical module and the optical fiber are respectively fixed to the first and second metal pipe members, and the first pipe member and the second pipe member are mutually bonded by laser welding. Since it is fixed, the conventional disadvantages caused by using adhesives are eliminated and reliability is improved. In the configuration of the present invention, the waveguide type optical module and the optical fiber are fixed in the first and second pipe members so that their end faces are exposed, and the vibration member is fixed with both end faces facing each other. This is to achieve high optical coupling efficiency when they are fixed together.

Example Embodiments of the present invention will be described below based on the drawings.

FIG. 2 is a configuration diagram of a waveguide type optical module used in an embodiment of the present invention, and is a waveguide type optical modulator module that intensity-modulates and outputs a manually generated laser beam with a constant intensity.
Hereinafter referred to as "module". ) 10 are shown.

This module 10 forms an optical waveguide section 14 in the shape of a combination of two Y-branch waveguides by diffusing Ti (titanium) in a flat waveguide substrate 12 made of L r N b O 3 . Branch portion 14 of wave portion 14
a.

The electrodes 16 and 18 for applying driving voltages are mounted on the electrodes 14b, respectively. Branch portion 14a, 1 of optical waveguide section
Since the refractive index of 4b changes depending on the direction of the applied electric field, etc., when a potential difference is applied between the mounted electrodes 16 and 18, the branched lights having the same phase will undergo different phase changes. On the other hand, since the optical waveguide section 14 is a single mode leading waveguide that propagates only the fundamental mode light, except for the Y branching section, when the phase difference of the branched lights is 0, the intensity of the output interference light is is maximum, and when the phase difference of the branched lights is π, the intensity of the interference light is minimum. Further, when the phase difference is between 0 and π, the interference light intensity corresponds to the phase difference. Thus, by varying the voltage applied to the mounted electrodes 16.18 in response to the modulation signal, the light intensity modulation function is achieved.

FIG. 3 shows the module 10 in the first embodiment of the invention.
It is a perspective view which shows the state fixed in a pipe member. 1st
The pipe member 24 is composed of a first part 20 and a second part 22, each of which is a halved cylindrical SUS material, and the first part 20 has a groove for accommodating the module IO. 20a, the second part 22 has the groove 20 of the first part.
A groove 22a is formed at a position corresponding to a. Both end surfaces of the module 10 are exposed so as to be flush with both end surfaces of the first pipe member 24, respectively. The first portion 20 and the second portion 22 of the first pipe member can be joined by, for example, laser welding. or,
In order to fix the module 10 in the groove 20a of the first part, Au (gold) may be vapor-deposited on each of the mutual contact surfaces of the module 10 and the groove 20a, and then fixed by soldering. In addition, the module IO is attached to the groove 20a using conductive adhesive.
It can also be fixed to The groove 22a is also formed in the second portion 22 of the first pipe member in the module 10.
This is to prevent the mounted electrodes 16, 18, etc. from coming into contact with the conductive second portion 22. In addition, mounted electrode 16
．． 18, for example, a through hole is formed on the side of the second portion 22 of the first pipe member, and a needle-like terminal is connected to the through hole through an insulator such as a glass material. This can be done by standing up the terminal and bringing this terminal into contact with the mounting electrodes 16 and 18.

FIG. 4 is a perspective view showing a state in which the optical fiber is fixed within the second pipe member in the embodiment of the present invention. The second pipe member 26 is constructed by continuously forming a small-diameter fiber insertion hole 26a and a large-diameter fiber-covered insertion hole 26b in a cylindrical SUS material along its geometric center axis. The optical fiber 28 from which the coating 30 near the tip has been removed is
The optical fiber 28 is inserted into the fiber insertion hole 26a so that its tip is exposed from the fiber insertion hole 26a, and the fiber coating 30 is inserted into the fiber coating insertion hole 26b.
The fiber coating 30 and the second vibe member 26 are bonded, for example, with an optical adhesive.

FIG. 5 shows the module 10 in the first embodiment of the invention.
FIG. 4 is a diagram for explaining an example of a method of fixing inside a pipe member 24. FIG. First, as shown in FIG.
a, and the module 10 is fixed in this groove 20a. On the other hand, a groove 22a is also formed in a cylindrical metal block 22'' which is to become the second part.
)), metal blocks 20° and 22° are brought into close contact with each other so that their grooved surfaces face each other, and after being integrated by laser welding, this integrated product is ground and polished to form the shape shown by P. It has a cylindrical outer shape. still,
Instead of integrating metal blocks and then forming them into a cylindrical outer shape, we cut the cylindrical metal block along a plane that includes its geometric center axis, form valley grooves, and insert modules into one groove. It is also possible to integrate the cut parts by fixing the module. FIG. 6 is a diagram for explaining another example of the method of fixing the module within the first pipe member in the embodiment of the present invention. . In this example, a notch 32a is formed in a cylindrical metal block, and after the module 10 is fixed in this notch 32a, the opening on the side surface of the pipe member of the notch 32a is closed with a lid member 34. . The lid member 34 and the first pipe member 32 are joined by, for example, laser welding.

A first pipe member 24 in which the module 10 is fixed.
Alternatively, when mutually fixing 32 and the second pipe member 26 into which the optical fiber 28 is inserted and fixed, the end face of the first pipe member from which the module 10 is coming out and the optical fiber 28 in the second pipe member are exposed. While monitoring the optical coupling efficiency between the module 10 and the optical fiber 28, the relative positional relationship between the first pipe member and the second pipe member is determined so that the optical coupling efficiency is maximized. The position may be determined by adjusting the position, and laser welding may be performed from the side of the contact surface at the determined position. For example, a YAG laser welder can be used for laser welding.

As described above, according to the present invention, since no adhesive is required to bond the portion holding the module 10 and the portion holding the optical fiber 28, reliability against temperature changes and the like is improved.

FIG. 7 shows a first pipe member and a second pipe member in an embodiment of the present invention.
It is a figure for explaining other examples of the method of fixing a pipe member by laser welding. In this example, instead of directly joining the first pipe member 24 and the second pipe member 26 by laser welding, both the vibe members 24 and 26 are inserted into the cylindrical member 36, and the first pipe member 24 and the second pipe member 26 are inserted into the cylindrical member 36. The cylindrical member 36 and the second pipe member 26 and the cylindrical member 36 are laser welded together. According to this structure,
The fixing strength between the two vibe members 24 and 26 is increased, and an intervening material such as silicone rubber (not shown) for refractive index matching can be easily interposed between the module 10 and the optical fiber 28.

As described in detail, according to the present invention, when connecting a waveguide type optical module and an optical fiber, there is no need for adhesive at the connection part, and reliability against temperature changes etc. is improved. play.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of the basic structure of the present invention, Fig. 2 is a configuration diagram of a waveguide type optical module used in the embodiment, and Fig. 3 is a diagram showing the configuration of the waveguide type optical module used in the embodiment. FIG. 4 is a perspective view showing a state in which the optical fiber is fixed in the second pipe member in the embodiment, and FIG. 5 is a perspective view showing the state in which the optical fiber is fixed in the first pipe member in the embodiment. FIG. 6 is a diagram for explaining another example of the method for fixing the waveguide type optical module in the first pipe member in the embodiment, and FIG. A diagram for explaining another example of the method of fixing the first pipe member and the second pipe member by laser welding in the embodiment, and FIG. 8 is an explanatory diagram of the prior art. 1.1 1a. 1, 2 3.2 4.2 0... Waveguide type optical module, 14... Leading cover, 4.32... First pipe member, 8... Optical fiber, 6... No. 2 pipe parts. (b) (C) Guo Rinko Shichi! Noel Hikari 4 left p 1st pief°aP) Mamotofupuibaroa 2nd By 1゜4 Azai O ζ Season 6e Moon base 48 Mitori 2 Zo no 5 also August (2) Fig. 1 2nd, Hikari Fiber Fukata Basita ° j 8... 1 child Fiber Kita 2nd Vibrator 4P
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Claims (1)

[Claims] Waveguide type optical module (1) having an optical waveguide (1a)
is fixed in the first metal pipe member (2) so that the end face of the optical waveguide (1a) is exposed, and the optical fiber (3) is fixed in the metal first pipe member (2) having a pore so that the end face is exposed. The first pipe member (2) is inserted and fixed into the second pipe member (4), and the end face of the optical waveguide (1a) and the end face of the core (3a) of the optical fiber (3) are opposed to each other. A connection structure for a waveguide type optical module and an optical fiber, characterized in that the second pipe member (4) is fixed by laser welding.