JP2002311287A - Optical coupling circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical coupling circuit, with which the warped deformation of an entire component caused by a temperature change can be suppressed and optical characteristics can be stabilized. SOLUTION: An optical coupling circuit 1 is provided with an optical fiber array 10 for fixing the terminal parts of optical fibers 2 and 3 on one side, an optical fiber ferrule 20 for fixing the terminal part of an optical fiber 4 on the other side and a base board 30 for fixing the optical fiber array 10 on one terminal part and fixing the optical fiber ferrule 20 on the other terminal part. The base board 30 is arranged with a lens 41, an optical filter 43 and another lens 42 corresponding to the lens 41 successively in the direction from the optical fibers 2 and 3 on one side to the optical fiber 4 on the other side. The lenses 41 and 42 are fixed in a guide groove 31 for positioning these lenses by an adhesive agent or the like. The optical filter 43 is fixed on an optical filter packaging member 46 fixed on the base board 30.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical coupling circuit for transmitting and receiving optical signals between optical fibers.

[0002]

2. Description of the Related Art As an optical coupling circuit of this type, for example, an optical coupling circuit disclosed in Japanese Patent Application Laid-Open No. H11-160569 is known. Japanese Patent Application Laid-Open No. 11-160569
An optical coupling circuit disclosed in Japanese Unexamined Patent Publication (Kokai) No. H11-20711 includes first and second optical fibers arranged such that end faces thereof face each other,
A first substrate to which the end of the first optical fiber is fixed; a second substrate to which the end of the second optical fiber is fixed;
And a third substrate provided between the first substrate and the second substrate. The third substrate includes a lens and an optical functional element ( For example, an optical isolator and / or an optical filter) and another lens corresponding to the above-described lens are provided.

The end of the first optical fiber is fixedly engaged with a V-groove formed on one surface of the first substrate. Second
The end of the optical fiber is fixed by engaging with a V-groove formed on one surface of the second substrate. Further, each lens is engaged with and fixed to a concave portion formed on one surface of the third substrate.

[0004]

By the way, in the optical coupling circuit having the above-mentioned configuration, the optical elements such as the optical fiber and the lens are fixed to separate substrates, respectively, and the substrates are aligned again. Must be fixed. Therefore, an extra assembling time is required for the step of joining the substrates, and an advanced assembling technique is required.

[0005] In order to solve the above problems,
It is conceivable to adopt a configuration in which the first substrate, the second substrate, and the third substrate are positioned by guide pins. However, it has been found that the following problems exist in the configuration in which the first substrate, the second substrate, and the third substrate are positioned by the guide pins.

If an adhesive containing a thermosetting resin (for example, epoxy resin) as a main component is used for attaching (adhering and fixing) the guide pins to the third substrate, the guide pins may be warped when cooled at room temperature. Occurs, making accurate positioning and adjustment difficult. Hereinafter, this point will be described in detail. The third substrate is usually made of a low expansion material such as Si or ceramics. On the other hand, the guide pin is SUS
And the like. As described above, since there is a difference in the coefficient of thermal expansion between the third substrate and the guide pin, when the third substrate is cooled to room temperature after being heated to a high temperature in order to cure an adhesive containing a thermosetting resin as a main component. Thermal deformation occurs, and warpage deformation occurs in the guide pin. As a result, the optical characteristics of the optical coupling circuit deteriorate.

Further, even if the first substrate, the second substrate, and the third substrate are aligned and fixed via the guide pins, there is a difference in the thermal expansion coefficient between the third substrate and the guide pins. In addition, when the environmental temperature changes, thermal deformation occurs, and warpage deformation occurs in the guide pin 144, thereby deteriorating the temperature characteristics of the optical characteristics in the optical coupling circuit.

The present invention has been made in view of the above points, and suppresses warping deformation of the entire component due to a temperature change.
It is an object to provide an optical coupling circuit capable of stabilizing optical characteristics.

[0009]

An optical coupling circuit according to the present invention comprises a first connection terminal to which one end of an optical fiber is fixed, and a second connection terminal to which the other end of an optical fiber is fixed. A connection substrate, and a base substrate having a first connection terminal fixed to one end thereof and a second connection terminal fixed to the other end thereof. It is characterized in that a lens, an optical functional element, and another lens corresponding to the lens are arranged in order in the direction toward the optical fiber.

In the optical coupling circuit according to the present invention, the first connection terminal is fixed to one end of the base substrate and the second connection terminal is fixed to the other end of the base substrate without using guide pins. Therefore, the warpage of the guide pin when using an adhesive containing a thermosetting resin as a main component as described above, and the warpage of the guide pin due to the heat deformation at the time of environmental temperature change does not occur. Warpage deformation of the entire part due to the change is suppressed. As a result, according to the present invention, the optical characteristics of the optical coupling circuit can be stabilized.

It is preferable that at least one of the connection terminals is fixed to the base substrate in a state where a predetermined side surface of at least one of the connection terminals and a predetermined side surface of the base substrate are positioned. With this configuration, the alignment of the optical axis of the optical fiber fixed to at least one of the connection terminals and the optical axis of the lens fixed to the base substrate can be realized easily and at low cost.

The base substrate is provided with a fixing portion into which at least one of the connection terminals can be inserted, and at least one of the connection terminals is inserted into the fixing portion and connected to the other connection element side. It is preferable that the optical axis is fixed while being adjusted. With this configuration, even if the alignment of the optical axis of the optical fiber fixed to the other connection element and the optical axis of the lens fixed to the base substrate is insufficient, the light in the entire optical coupling circuit is not affected. Axis alignment can be performed reliably.

Preferably, at least one of the connection terminals has a cylindrical side surface, and the fixing portion is made of a pipe member. With this configuration, even if the alignment between the optical axis of the optical fiber connected to the other connecting element and the optical axis of the lens fixed to the base substrate is insufficient, the optical axis alignment of the entire optical coupling circuit is performed Can be realized simply and at low cost.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of an optical coupling circuit according to the present invention will be described below in detail with reference to the drawings. In the embodiment described below, the optical coupling circuit of the present invention is provided with a 2 × 1 WDM (Wavelength Division Multiplexin).
g) This is an example applied to a filter.

The configuration of an optical coupling circuit according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a perspective view showing an optical coupling circuit according to the present embodiment, and FIG.
FIG. 3 is a side view showing the optical coupling circuit. FIG.
FIG. 3 is a cross-sectional view along the optical axis direction in the optical coupling circuit according to the present embodiment.

As shown in FIGS. 1 to 3, the optical coupling circuit 1 includes an optical fiber array (first connection terminal) 10, an optical fiber ferrule (second connection terminal) 20, a base substrate 30, and a pair of The optical system includes lenses 41 and 42, an optical filter 43 as an optical functional element, and the like. Optical fiber array 1
0 is fixed to one end of the base substrate 30. The optical fiber ferrule 20 is fixed to the other end of the base substrate 30. The optical fiber array 10 and the optical fiber ferrule 20 are arranged in series on a base substrate 30.

The optical fiber array 10 has a substantially rectangular parallelepiped shape, and is made of a low expansion material such as a Si substrate, quartz glass or ceramics. Optical fiber array 1
As shown in FIG. 4, an optical fiber positioning V-groove 11 extending in a direction parallel to the direction in which the optical fiber array 10 and the optical fiber ferrule 20 are arranged on one surface (lower surface) of the optical fiber ferrule 20.
(For example, three) are formed. In the first embodiment, the ends of the optical fibers 2 and 3 are fixed to each of the two optical fiber positioning V-grooves 11.

Each of the optical fibers 2 and 3 is positioned such that the end faces of the optical fibers 2 and 3 are positioned on the side of the optical fiber array 10 on the optical fiber positioning V-groove 11. Fiber array 10) and fixing member 1
2 and fixed with an adhesive (for example, an epoxy resin-based adhesive or the like). Alternatively, the optical fibers 2 and 3 are fixed with an adhesive or the like while being sandwiched between the optical fiber positioning V-groove 11 and the fixing member 12 with the optical fibers 2 and 3 slightly protruding from the end faces, and then the end faces are cut with a dicer or the like to cut the end faces. Align.

On one surface (upper surface) of the optical fiber array 10, a pair of V grooves 13 extending in parallel with the optical fiber positioning V groove 11 are formed with the optical fiber positioning V groove 11 interposed therebetween. Optical fibers 6 other than the optical fibers 2 and 3 through which signals are transmitted are fixed to the V-groove 13. Thereby, when the optical fibers 2 and 3 are fixed, the posture and the position of the fixing member 12 are stabilized, and the positioning of the optical fibers 2 and 3 can be performed easily and accurately.

Optical fiber ferrule (second connection terminal)
Reference numeral 20 denotes a ferrule for a single-core optical connector, which is made of metal or ceramics. Optical fiber ferrule 20
Has a tip portion 21 having a cylindrical side surface and a flange portion 23. The optical fiber insertion hole 2 is located at the center of the tip portion 21.
2 are provided. In this optical fiber insertion hole 22,
The end of the optical fiber 4 is inserted and fixed.

The base substrate 30 is formed of the optical fiber array 10
In the same manner as described above, a lens positioning guide groove 31 which is made of a low expansion material such as a Si substrate, quartz glass or ceramics and extends in the longitudinal direction is formed. The lens positioning guide groove 31 extends in a direction parallel to the direction in which the optical fiber array 10 and the optical fiber ferrule 20 are arranged.
This is for positioning the lenses 41 and 42. As shown in FIG. 6, a spherical lens (a so-called ball lens) is used for each of the lenses 41 and 42, and an adhesive (for example, an epoxy resin-based adhesive or the like) is attached to the lens positioning guide groove 31. Is fixed by

The base substrate 30 has fixed portions 3 at both ends.
3, 37 are provided. The fixing portion 33 is for mounting and fixing the optical fiber array 10, and has a V-groove 34 for filling with an adhesive. Also, the fixing part 33
Is precisely machined as a reference surface for positioning the optical fiber array 10. The side surface 15 of the optical fiber array 10 has a distance from the side surface 15 of the optical fiber array 10 to the center of the optical fiber positioning V-groove 11 to which the optical fiber 2 is fixed. ) To the center of the lens positioning guide groove 31.

The fixing portion 37 is formed of a pipe member, and is configured such that the distal end portion 21 of the optical fiber ferrule 20 can be inserted. The fixing portion 37 (pipe member) is fixed to the lens positioning guide groove 31 with an adhesive (for example, an epoxy resin adhesive). In addition, separately from the lens positioning guide groove 31, the fixing portion 37 (pipe member)
May be formed by machining.

The optical filter 43 transmits the signal light having a predetermined wavelength among the incident signal lights and reflects the signal light having a wavelength other than the predetermined wavelength, and is a pair of one surface (upper surface) of the base substrate 30. Are disposed at positions between the lenses 41 and 42. The optical filter 43 is attached to the mounting portion 39 of the base substrate 30 with an adhesive (for example, an epoxy resin adhesive).
Is mounted on the optical filter mounting member (optical functional element mounting member) 46 fixed by, for example, and fixed by an adhesive (for example, an epoxy resin adhesive). The arrangement position of the optical filter 43 is a position where the optical coupling efficiency at the end of each optical fiber is maximized. The optical filter 43 may be directly fixed to one surface of the base substrate 30 with an adhesive or the like without using the optical filter mounting member 46.

Next, the operation of the optical coupling circuit 1 configured as described above will be described.

The optical fiber ferrule 20 of the optical fiber 2
The signal light emitted from the end face on the side becomes a parallel beam having a predetermined diameter after passing through the lens 41 and enters the optical filter 43. Of the signal light incident on the optical filter 43, the signal light of a predetermined wavelength passes through the optical filter 43 and enters the lens 42, and the signal light incident on the lens 42 is condensed by the lens 42 and guided to the optical fiber 4. I will On the other hand, the signal light having a wavelength other than the predetermined wavelength reflected by the optical filter 43 enters the lens 41, and the signal light entering the lens 41 is condensed by the lens 41 and guided to the optical fiber 3.

Next, the procedure for mounting optical components in the optical coupling circuit 1 having the above-described configuration will be described.

First, the lenses 41 and 4 are provided on the base substrate 30.
2. The optical filter mounting member 46 is fixed. Lens 41,
As described above, the fixing of 42 is performed using an adhesive in the lens positioning guide groove 31. The fixing of the optical filter mounting member 46 is performed using an adhesive (for example, an epoxy resin-based adhesive) on the mounting portion 39 formed by removing a central portion of the base substrate 30 by a predetermined depth. .

Next, the optical fiber array 10 to which the ends of the optical fibers 2 and 3 are fixed is fixed to the fixing portion 33 of the base substrate 30.
And the optical filter 43 is fixed to the optical filter mounting member 46. To fix the optical fiber array 10, the optical fiber array 10 is placed on the fixing portion 33, the side surface 15 of the optical fiber array 10 is flush with the side surface 35 (reference surface) of the fixing portion 33, and the focal position of the lens 41 is set. (Position adjustment in the optical axis direction of the optical fibers 2 and 3 of the optical fiber array 10) and the like,
This is performed by injecting and curing an adhesive from the groove 13. Accordingly, the optical fiber array 10 can be fixed to the base substrate 30 in a state where the optical axis of the lens 41 fixed to the lens positioning guide groove 31 and the optical axis of the optical fiber 2 are substantially aligned.

The optical filter 43 is fixed by inserting the optical filter 43 into a slit 47 formed on one surface (upper surface) of the optical filter mounting member 46 and adjusting the position (angle) thereof.
The gap between the optical filter 7 and the optical filter 43 is filled with an adhesive (for example, an epoxy resin adhesive) and cured. In addition to the fixing with the adhesive, the optical filter 43
Alternatively, a metal may be deposited on a surface other than the light incident / exit surface and fixed to the optical filter mounting member 46 by soldering. At this time, it is necessary that the optical filter mounting member 46 is formed of metal or metal is deposited on the surface of the slit portion.

Then, the optical fiber ferrule 20 to which the end of the optical fiber 4 is fixed is fixed to the fixing portion 3 of the base substrate 30.
Fix to 7. The optical fiber ferrule 20 is fixed by inserting the distal end portion 21 into a fixing portion 37 (pipe member) and moving the inside of the fixing portion 37 by using a jig of six-axis control to fix the optical fiber to the optical fiber ferrule 20. Of the optical axis of the optical fiber 4 and the optical axis of the optical fiber 2 fixed to the optical fiber array 10, and adjustment of the focal position of the lens 42 (position adjustment of the optical fiber ferrule 20 in the optical axis direction of the optical fiber 4). After performing the above steps, the optical fiber ferrule 2
This is performed by filling and curing an adhesive (for example, an epoxy resin-based adhesive or the like) between the zero and the fixing portion 37.

According to the procedure described above, the optical components are mounted and the optical coupling circuit 1 is completed. In the optical coupling circuit 1, the optical fiber array 10 is fixed to one end of the base substrate 30, the optical fiber ferrule 20 is fixed to the other end, and one of the optical fibers 2 and 3 (optical fiber A lens 41, an optical filter 43, and a lens 42 are provided in this order from the array 10) to the other optical fiber 4 (optical fiber ferrule 20).

As described above, in the optical coupling circuit 1 according to the present embodiment, the end of one optical fiber 2 or 3 is fixed to the optical fiber array 10 and the end of the other optical fiber 4 is fixed. An optical fiber ferrule 20 and an optical fiber array 10 are fixed at one end, and a base substrate 30 to which the optical fiber ferrule 20 is fixed at the other end. A lens 41, an optical filter 43, and another lens 42 corresponding to the lens 41 are arranged in this order from the optical fiber 4 to the other optical fiber 4. As a result, the optical fiber array 10 is fixed to one end of the base substrate 30 and the optical fiber ferrule 20 is fixed to the other end of the base substrate 30 without using guide pins. Of the guide pin when using an adhesive containing a conductive resin as a main component, and without warping of the guide pin due to thermal deformation when the environmental temperature changes. Will be suppressed. As a result, according to the optical coupling circuit 1 according to the present embodiment, the optical characteristics of the optical coupling circuit 1 can be stabilized regardless of the temperature change.

In the optical coupling circuit 1 according to the present embodiment, the optical fiber array 10 is
The base plate 30 is fixed to the base substrate 30 in a state where the side surface 15 and the side surface 35 of the base substrate 30 are positioned. Thus, the alignment of the optical axes of the optical fibers 2 fixed to the optical fiber array 10 and the optical axes of the lenses 41 and 42 fixed to the base substrate 30 can be realized easily and at low cost.

In the optical coupling circuit 1 according to the present embodiment, the optical fiber ferrule 2 is provided on the base substrate 30.
The optical fiber ferrule 20 is fixed in a state where the distal end portion 21 is inserted into the fixing portion 37 and the optical axis is adjusted to the optical fiber array 10 side. Is done. Thus, even if the alignment between the optical axis of the optical fiber 2 fixed to the optical fiber array 10 and the optical axes of the lenses 41 and 42 fixed to the base substrate 30 is insufficient, the entire optical coupling circuit 1 can be adjusted. Can be reliably performed.

In the optical coupling circuit 1 according to the present embodiment, the distal end portion 21 of the optical fiber ferrule 20 has a cylindrical side surface, and the fixing portion 37 is made of a pipe member. Thus, even if the alignment between the optical axis of the optical fiber 2 fixed to the optical fiber array 10 and the optical axes of the lenses 41 and 42 fixed to the base substrate 30 is insufficient, the entire optical coupling circuit 1 can be adjusted. Can be easily and inexpensively realized.

The present invention is not limited to the above-described embodiment, but includes the number of optical fibers 2, 3, and 4 fixed to the optical fiber array 10 and the optical fiber ferrule 20.
The shapes and materials of the optical fiber array 10, the optical fiber ferrule 20, the base substrate 30, the shape of the lens positioning guide groove 31 formed in the base substrate 30, and the like are not limited to those described above. Also, the optical function element used is not limited to the optical filter 43, and for example, an optical isolator may be used. Further, the lenses 41 and 42 used are not limited to spherical lenses, and cylindrical lenses such as gradient index lenses may be used.

In the present embodiment, the optical fiber array 10 is fixed to one end of the base substrate 30 and the optical fiber ferrule 20 is fixed to the other end.
Without being limited to this, the optical fiber array 10 may be fixed to one end and the other end of the base substrate 30. Further, the optical fiber ferrule 20 may be fixed to one end and the other end of the base substrate 30.

In the present embodiment, the positioning of the optical fiber array 10 is performed by using the side surface 15 of the optical fiber array 10 and the side surface 35 (reference surface) of the fixing portion 33. Without being limited to this, the positioning of the optical fiber array 10 and the base substrate 30 may be performed using a jig or the like.

In this embodiment, the fixing portion 37
However, the present invention is not limited to this.
May be used.

In this embodiment, an optical filter is used as the optical functional element of the present invention to constitute a 2 × 1 WDM filter. However, the present invention is not limited to this, and the present invention is applicable to various optical devices. can do. For example, by using an optical isolator, an optical coupler, and a grating as the optical functional element, it is possible to form an optical component having a branching function according to the wavelength.

[0042]

As described above in detail, according to the present invention, there is provided an optical coupling circuit capable of suppressing the warpage of the entire component due to a change in temperature and stabilizing the optical characteristics. Can be.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an optical coupling circuit according to an embodiment of the present invention.

FIG. 2 is a side view showing the optical coupling circuit according to the embodiment of the present invention.

FIG. 3 is a cross-sectional view along an optical axis direction in the optical coupling circuit according to the embodiment of the present invention.

FIG. 4 is a sectional view taken along the line IV-IV in FIG. 3;

FIG. 5 is a sectional view taken along the line VV of FIG. 3;

FIG. 6 is a sectional view taken along the line VI-VI in FIG. 3;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Optical coupling circuit, 2, 3, 4 ... Optical fiber, 10 ... Optical fiber array (1st connection terminal), 11 ... Optical fiber positioning V groove, 12 ... Fixing member, 15 ... Side surface, 20 ... Optical fiber Ferrule (second connection terminal), 21: tip portion, 22: optical fiber insertion hole, 30: base substrate, 31
... Guide grooves for lens positioning, 33 ... Fixed part, 35 ... Side, 37 ... Fixed part, 41,42 ... Lens, 43 ... Optical filter (optical functional element), 46 ... Optical filter mounting member.

Continued on the front page. (72) Inventor Tomomi Sano 1 Tayacho, Sakae-ku, Yokohama-shi, Kanagawa Prefecture Sumitomo Electric Industries, Ltd. Yokohama Works (72) Inventor Mitsuaki Tamura 1-Tagamachi, Sakae-ku, Yokohama-shi, Kanagawa Sumitomo Electric Industries F term in Yokohama Works (reference) 2H037 AA01 BA32 CA14 CA21 DA04 DA05 DA12 DA15

Claims (4)

[Claims] 1. A first connection terminal to which an end of one optical fiber is fixed, a second connection terminal to which an end of another optical fiber is fixed, and the first connection terminal to one end. And a base substrate to which the second connection terminal is fixed to the other end portion. The base substrate has a lens in order from the one optical fiber to the other optical fiber. And an optical functional element, and another lens corresponding to the lens. 2. At least one of the connection terminals is fixed to the base substrate in a state where a predetermined side surface of at least one of the connection terminals and a predetermined side surface of the base substrate are positioned. The optical coupling circuit according to claim 1, wherein: 3. The base substrate is provided with a fixing portion into which at least one of the connection terminals can be inserted, and at least one of the connection terminals is inserted into the fixing portion and the other of the connection terminals is inserted into the other. The optical coupling circuit according to claim 1, wherein the optical coupling circuit is fixed with the connection element side and the optical axis adjusted. 4. The optical coupling circuit according to claim 3, wherein at least one of the connection terminals has a cylindrical side surface, and the fixing portion is made of a pipe member.