JPS63291010A - Optical waveguide module - Google Patents

Abstract

PURPOSE:To prevent optical coupling efficiency from decreasing by peeling the clad of an optical fiber in a specific section and exposing the fiber core, and slackening the fiber core until it can be deformed. CONSTITUTION:The clad of the optical fiber 1 in the section from where the fiber 1 is fixed to a housing 5 to the tip which is connected to an optical waveguide to expose the fiber core 2, which is slackened until it can be deformed. In this case, the fiber core 2 is slackened so that neither deformation nor expansion of an enclosure 5 extends directly to an optical waveguide/fiber connection part. Therefore, even if an external force or heat is applied or conducted to the enclosure 5 of a module, its influence never extends to the connection part between the optical waveguide and optical fiber 11. Consequently, a decrease in optical coupling efficiency due to the relative dislocation between the fiber 1 and waveguide is evaded.

Description

[Detailed Description of the Invention] [Summary] An optical waveguide module having an optical waveguide substrate housed in a housing and an optical fiber connected to the optical waveguide, wherein the optical fiber in the housing is only a core wire. It is characterized by being in this state and being relaxed to the extent that it can be deformed. In this optical waveguide module, the connection between the optical waveguide and the optical fiber is stable and reliable, and problems such as a decrease in light coupling efficiency can be avoided.

[Industrial application field]

The present invention relates to an optical waveguide module. More specifically, the present invention relates to an optical waveguide module of a type having an optical waveguide substrate housed in a housing and an optical fiber connected to the optical waveguide of the substrate and fixed to the housing. The optical waveguide module of the present invention can be advantageously used, for example, in fields such as optical communication and sensors using light.

[Conventional technology]

With the development of optical communication waves +rFj, miniaturization, integral formation, mass production, etc. of optical circuit elements are required. Similar demands exist in the field of sens 'IJ' using yi, and as a device form that meets these demands,
Optical waveguide module 1. − has been proposed. By the way, when manufacturing an optical waveguide module, the connection between the optical waveguide and the optical fiber becomes a problem. This is because, in addition to the problem of using the sizes of the two, optical fibers, especially their cores (core and cladding layer surrounding it), have the well-known 1ff
Since it is extremely thin and made of a material such as glass, it does not have sufficient mechanical strength, so careful handling is required. This is because connections must be made in a manner that avoids inconveniences such as axial misalignment, angular misalignment, and separation of end faces.

Therefore, conventionally, in order to manufacture an optical waveguide module by connecting optical waveguide Q-type fibers, the connection method schematically shown in FIGS. 4 and 5 has been widely used. In Fig. 4, when the optical fiber (sheath is cut) 1 is fixed to the housing 5, fiber core vA2 is embedded in the /# of the fiber array 3, which has a V-shaped groove in the silicon substrate, and adhesive is applied. etc., and then press it down from above with a glass plate (not shown). After processing the end face of the fiber core 2 of the fiber array 3 by polishing, etc., The optical waveguide 14 formed above is aligned with the optical waveguide 14 using a fine movement table or the like, and fixed with adhesive.

Similarly, modularization as shown in FIG. 5 is also possible. In this example, instead of fixing the optical fiber 1 to the housing with a vinyl coat (tI' jacket) attached to protect the fiber core 2, the fiber core 2 is The fiber array 3, which is pressed into a V-groove or the like and fixed with an adhesive or the like, is further fixed to the housing.

[Problem that the invention attempts to solve]

Conventional optical waveguide mosifs, however, have problems that must be solved. Of course, if the casing that houses the waveguide substrate and to which the optical fiber or fiber array is fixed is deformed by external force or expands due to heat, the waveguide and optical fiber may undergo such changes. This directly affects the connecting portion and therefore shifts the relative position between the fiber and the waveguide, resulting in a reduction in coupling efficiency7 and, if worse, causes problems such as end-face separation.

[Failure to solve the problem]

The present inventors recently peeled off the outer sheath of the optical fiber between the identified part on the housing and the tip connected to the optical wind wave path, exposed the fiber core, and deformed the fiber core. It has been found that the above-mentioned problems can be solved by an optical waveguide module characterized by being loosened to the extent possible.

In implementing the present invention, the slack in the fiber core must be set to such an extent that it can be deformed, that is, the slack in the fiber core must be such that deformation and expansion of the casing do not directly affect the optical waveguide Pi/fiber connection. be. However, excessive slack must be avoided as it may cause the core wire to break. In addition, if the fiber core is exposed before the core is loosened, there is a risk that the core may break when the slack is formed. method is recommended.

The fiber cores can be connected to the optical waveguide, for example, via a fiber array in which the core wires are formed in grooves 1'4 of a silicon substrate. However, in order to achieve greater bonding strength and reduce mossy pool loss, it is particularly recommended that the optical waveguide and the fiber core be connected through a small piece that fits and secures the tip of the core wire into the pore. be done.

In the optical waveguide module according to the present invention, the connection between the casing and the optical waveguide/optical fiber connection section is loosely made using only the fiber core wire, so that external forces applied to the casing are The optical waveguide/optical fiber connection section is not directly affected by the effects of heat and heat. Moreover, in this module 1, unexpectedly large bonding strength can be achieved as a result of the combination of the bonding between the fiber core and the small piece and the bonding between the small piece and the waveguide substrate. At this time, since the small piece is small and lightweight, there is no stress on the fiber core, and the core itself can hold the small piece, so that the X, Y, Z alignment can be as precise as the alignment of the fiber alone. Axis and angle adjustments are possible.

〔Example〕

The optical waveguide module according to the present invention can have a structure as shown in cross section in FIG. 1, for example. A waveguide substrate 4′ is housed in a casing 5 made of stainless steel.
Moreover, the optical fiber 1 is fixed. The core wire 2 of the optical fiber 1 is bonded to the end face of the waveguide substrate 4 . As shown in FIG. 2, the optical fiber core 2 is held in a V-groove of a silicon substrate 6 using a holding plate 7.

The combination of the substrate 6 and the holding plate 7 is referred to as a fiber array 3 here. Further, the fiber core wire 2 is given slack as shown in the figure. The waveguide substrate 4 is a substrate made of electro-optic crystal such as lithium niobate (LiNbO:+), on which an optical waveguide (not shown) is formed by thermal diffusion of titanium, for example.

The connection of the optical fiber to the optical waveguide further preferably includes:
This can be done as illustrated in FIG. The fiber core 2 can be bonded to the optical m-wavepath (not shown) of the waveguide substrate 4 via the small piece 13 .

To explain the connection method in Fig. 3 in an easy-to-understand manner, the small piece 13 is
An optical fiber core 2 (made up of a core and a cladding layer with an outer sheath such as a vinyl coat removed) is fitted into the pore, and is firmly bonded with an adhesive (not shown). There is. In order to obtain stronger bonding force, it is recommended to use heat fusion for bonding with adhesive. Further, the small piece 13 is bonded to the end face of the waveguide substrate 4 via an adhesive layer (not shown), and in this case, the end face of the optical waveguide (not shown) and the tip of the fiber core 2 are small piece 1
3 is small and lightweight, so it is precisely aligned. Since the alignment is performed correctly, the module loss of this connection method is almost zero.

The piece 13 shown in FIG. 3 is preferably a ruby ring and has a pore and a recess. The four parts serve as a guide when inserting the fiber core into the hole, which is very convenient. In addition, this ruby ring can process pores with an accuracy of ±llN1 or less relative to the diameter of the fiber core wire.
Its processing is also possible easily and inexpensively. As necessary,
For example, diameter 1.2, thickness 400ttm and pore size 13
A ruby bearing for a watch having a zero storage can also be applied to this.

〔Effect of the invention〕

According to the present invention, even if external force or heat is applied to the module housing, these effects do not extend to the connection between the optical waveguide and the optical fiber. It is possible to avoid problems such as a decrease in coupling efficiency. Further, according to the present invention, it is possible not only to reduce module loss, but also to improve bonding strength, reduce man-hours, reduce processing cost, member cost, etc.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a preferable example of an optical waveguide module according to the present invention, FIG. 2 is a perspective view showing an example of a method of connecting a fiber core to a waveguide, and FIG. Another method of connecting the core wire to the waveguide
A perspective view showing two examples, and FIGS. 4 and 5 are schematic diagrams showing examples of conventional optical waveguide modules, respectively. In the figure, 1 is an optical fiber, 2 is a fiber core, 3 is a fiber array, 4 is a waveguide substrate, 5 is a housing, 13 is a small piece, and 14 is an optical waveguide.

Claims (1)

[Claims] 1. Peel off the outer sheath of the optical fiber between the part fixed to the housing and the tip connected to the optical waveguide to expose the fiber core and make the fiber core wire deformable. An optical waveguide module characterized by being relaxed. 2. The optical waveguide module according to claim 1, wherein the fiber cores are connected to the optical waveguide via a fiber array in which the core wires are embedded in a V-groove. 3. Claim 1, in which the fiber core wire is connected to the optical waveguide through a small piece that fits and fixes the core wire into the pore.
The optical waveguide module described in .