JP2003131099A - Optical element and optical component provided with optical element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical element used in an optical communication system, etc., and an optical component provided with the optical element which do not increase the manufacturing cost, are small in size and have good optical characteristics. SOLUTION: The optical component is constituted by having a light transmitting region 2 thorough which light is transmitted and other Faraday rotators 21, 21' are stacked in the light transmitting direction and fixed to a supporting member 10. The side ends 6, 7 to be coated with an organic adhesive 12 and grooves 4, 5 formed opposite to other Faraday rotator 21, 21' in the vicinity of the side ends 6, 7 so as to prevent the organic adhesive 12 entering the light transmitting region 2, are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical element used in an optical communication system or the like and an optical component including the same.

[0002]

2. Description of the Related Art Wavelength Division Multiplexing (WDM)
gth Division Multiplexin
g) As represented by optical communication systems, the speed and capacity of optical communication systems are increasing. The devices that make up the optical communication system are configured by combining various optical components. Each optical component is configured by further combining various materials such as an optical element and a metal member.

Many methods have been proposed and put to practical use for assembling and fixing an optical element in a housing member made of a metal material or the like when assembling an optical component. The method includes fixing by adhesion using an organic adhesive, solder, low melting point glass, or the like, or fixing by pressure bonding using a plastically deformable metal member, as disclosed in JP-A-6-186425. Is used.

Each of the above fixing methods has advantages and disadvantages. In the case of adhesive fixation using an organic adhesive, (1) application to a member is easy, (2) unlike adhesive fixation using solder, metallizing treatment on the surface of the member is unnecessary,
(3) It has the advantage that the stress generated in the fixed optical element is small. On the other hand, adhesive fixation using organic adhesive is
(1) Outgas is generated from the organic adhesive at a high temperature (about 60 to 80 ° C.), (2) The organic adhesive protruding in the light transmitting region deteriorates when exposed to high-intensity light, (3) solder or Compared with adhesive fixation using low melting point glass, it has inferior long-term reliability and (4) it takes a long time to cure.

[0005]

[Problems to be Solved by the Invention] Japanese Patent Application No. 62-3684
According to the specification described in No. 3 microfilm, a shallow groove is provided in a housing member that holds an optical element, and an adhesive is applied to the shallow groove to fix the optical element, whereby the light transmitting region is protected. A method of preventing penetration of the adhesive is disclosed. However, this method is supposed to fix optical elements such as cubic prisms, which are relatively thick, and to prevent adhesive penetration when fixing multiple plate-shaped optical elements that are relatively thin. There is no description for it.

Even if only one plate-shaped optical element is adhered and fixed to the housing member, the adhesive does not penetrate into the light transmitting area because the light transmitting area is not in contact with the housing member. Absent.

However, when two or more optical elements are directly superposed and fixed to the housing member by adhesion, the organic adhesive before being cured into the space between the two optical elements due to the capillary phenomenon due to the fluidity of the organic adhesive. Permeate and cause poor adhesion. As shown on the left side of the graph in FIG. 7, in the conventional optical component, adhesion failure occurs with a probability of about 34%, which is difficult to control. FIG. 10A shows a configuration in which the optical component 120 in which adhesion failure due to permeation has occurred is viewed perpendicularly to the optical signal transmission direction. In addition, FIG.
(B) shows the configuration of the optical component 120 viewed in the transmission direction of the optical signal. As shown in FIGS. 10 (a) and 10 (b),
The optical component 120 is composed of three optical elements 11 that are superposed on each other.
2 is fixed to the holding member 110 with an organic adhesive 116. The holding member 110 has an opening 122 for transmitting an optical signal. Opening 122
Thus, the light transmitting region 114 surrounded by the virtual line β of the optical element 112 is determined. As shown in FIG. 10B, the organic adhesive 116 applied from the adhesive injection port 118 of the holding member 110 to the edge portions 106 and 107 of each optical element 112 is the edge portion 106, due to the capillary phenomenon. It extends from 107 to the light transmitting region 114.

Depending on the optical component 120, the light transmitting region 1
In some cases, organic adhesive 116 may be present on 14. However, in general, the organic adhesive 116 is
When it penetrates 4, the organic adhesive 11
6 not only deteriorates, but also the optical characteristics of the optical component 120 deteriorate, such as an increase in loss.

To prevent the phenomenon of penetration due to capillary action,
The gap between the optical elements 112 to be overlapped may be widened. As a method of widening the gap, it is conceivable to sandwich a spacer between the optical elements 112 or to form a groove on the holding member 110 side for fixing the optical elements 112 one by one in a predetermined arrangement. However, these methods have a problem that the manufacturing cost increases and the optical component 120 becomes large.

There is also a method of fixing the optical elements 112 one by one to the individual holding members 110 and then combining them to manufacture the optical component 120.
There is a problem that the structure of 12 becomes complicated and the manufacturing cost increases.

An object of the present invention is to provide a small-sized optical element having excellent optical characteristics and an optical component including the same, without increasing the manufacturing cost.

[0012]

An object of the invention is to apply an adhesive when a light transmitting region for transmitting light and another element in the light transmitting direction are overlapped and fixed to a holding member. An optical element characterized by having an edge portion and a groove formed so as to face the other element in the vicinity of the edge portion in order to prevent the adhesive from penetrating into the light transmitting region. Achieved by

The optical element of the present invention is characterized in that the groove portion is formed substantially parallel to the edge portion.

Further, the above object is an optical component having a plurality of optical elements stacked in the light transmitting direction and a holding member for holding the optical element, wherein the optical element is defined in claim 1 or 2. It is achieved by an optical component characterized in that it comprises the described optical element.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the basic structure and principle of the present invention will be described with reference to FIG. FIG. 1A shows the basic configuration of the present invention, and is a view of the optical component 28 as seen in a direction in which an optical signal is transmitted. FIG. 1B shows an optical component 28.
FIG. 3 is a perspective view showing the arrangement of a plurality of optical elements 21 and 21 ′ that configure the above. FIG. 1C is a perspective view showing the configuration of one optical element 21. As shown in FIGS. 1A and 1B, the optical component 28 has a configuration in which a plurality of optical elements 21 are directly overlapped with each other and incorporated in a holding member 10 to be held. The optical element 21 has a light transmission region 2 surrounded by a virtual line α. The light transmitting region 2 is adapted to transmit an optical signal that travels perpendicularly to the paper surface. The shape and size of the light transmission region 2 are determined by the opening 14 formed in the holding member 10 as described later.

Further, as shown in FIG. 1C, the optical element 2
1 has a linear groove portion 4 which is substantially parallel to the edge portion 7 in the vicinity of the edge portion 7 above the light transmission region 2 in the figure. Further, the optical element 21 has a linear groove portion 5 substantially parallel to the edge portion 6 in the vicinity of the edge portion 6 below the light transmission region 2 in the figure.

A plurality of optical elements 21 are overlapped with each other with a predetermined space therebetween, and an edge portion 6 is provided with an adhesive injection port portion 16.
They are fixed to each other by the organic adhesive 12 applied to the sheet 7, and also fixed to the holding member 10. Each optical element 21 is arranged so that the groove portions 4 and 5 face the adjacent optical element 21.

As shown in FIG. 1A, the organic adhesive 12
(Indicated by hatching in the figure) does not penetrate into the light transmission region 2 side from the groove portions 4 and 5. This is because when the organic adhesive 12 that permeates from the vicinity of the central portion of the end side portion 7 (end side portion 6) of the optical element 21 reaches the groove portion 4 (groove portion 5), it follows along the groove portion 4 (groove portion 5). This is because it spreads and does not penetrate to the light transmission region 2 side.

In general, liquids have the property that they tend to be united by the cohesive force of the molecules that make up the liquid. When the liquid and the solid are in contact with each other at the interface, an adhesive force acts between the liquid and the solid. This adhesive force causes a capillary phenomenon. The above-mentioned cohesive force and adhesive force are both forces related to the surface tension of the liquid.

The grooves 4 and 5 formed in the vicinity of the edges of the optical element 21 are areas where the organic adhesive 12 aggregates. When the cohesive force becomes larger than the force that penetrates between the optical elements 21 due to the capillary phenomenon, the organic adhesive 12 can be prevented from penetrating into the light transmitting region 2. That is, the groove portions 4, 5
Has a function of uniformly dispersing the organic adhesive 12 in a direction parallel to the edge portions 6 and 7 and preventing the organic adhesive 12 from permeating. It should be noted that each of the optical elements 21 includes the end portion 7 to the groove 4
To the holding member 10 with sufficient strength by the adhesive force of the organic adhesive 12 that permeates and hardens in the region up to and from the edge portion 6 to the groove portion 5.

Next, an optical element and an optical component including the same according to an embodiment of the present invention will be described with reference to FIGS. FIG. 2 shows the configuration of the optical element according to the present embodiment as viewed in the light signal transmission direction. See also FIG.
Shows a cross section of the optical element taken along the line AA in FIG. It should be noted that components having the same function and action as those of the optical component shown in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted. In this embodiment, the Faraday rotator 1 is used as the optical element. As shown in FIGS. 2 and 3,
The Faraday rotator 1 has, for example, a width W1 (for example, 1 m
m), the length L1 (for example, 1 mm) and the thickness T1 (for example, 0.3 mm). The Faraday rotator 1 has a diameter d1 when viewed in the transmission direction of the optical signal.
It has a circular light transmission region 2 (for example, 0.7 mm). An optical signal beam having a diameter of about 0.4 mm enters the light transmitting region 2 perpendicularly to the paper surface and is transmitted therethrough. In the vicinity of the edge portion 7 (edge portion 6) of the Faraday rotator 1, a groove portion 4 (groove portion 5) parallel to the edge portion 7 (edge portion 6) is provided.
Is formed

As shown in FIG. 3, the groove 5 has a U-shaped cross section, for example, and has a width W2 (for example, 0.025).
mm) and a depth D1 (for example, 0.05 mm). The groove portion 5 is arranged such that the inner wall surface of the groove portion 5 on the left side in the drawing is separated from the end side portion 6 of the optical element 1 by a width W3 (for example, 0.5 mm). The groove portion 4 shown in FIG. 2 also has the same structure as the groove portion 5.

Next, the structure of the optical component according to this embodiment will be described with reference to FIGS. FIG. 4 is a perspective view showing the configuration of the optical component 28, and FIG. 5 is an optical component 28.
Is viewed in the direction of arrow a in FIG. As shown in FIGS. 4 and 5, in the optical component 28, two Faraday rotators 1 according to the present embodiment and one Faraday rotator 1 ′ in which the grooves 4 and 5 are not formed are optical signals. And the holding member 1 is overlapped with the organic adhesive 12 in the transmission direction of
It has a configuration fixed to 0. The Faraday rotator 1 having the grooves 4 and 5 is arranged so that the grooves 4 and 5 face the surfaces of the adjacent Faraday rotators 1 and 1 ′.

The holding member 10 has a U-shape when viewed from the direction of arrow a in FIG. 4, and is made of, for example, stainless steel. The holding member 10 has a width W4 (for example, 3 mm), a thickness T2 (for example, 0.5 mm), and a thickness T3 (for example, 0.7 mm). The holding member 10 is
An opening portion (light transmission aperture) 14 opened to transmit an optical signal is provided on the right side in FIG. 5, and an opening for injecting the organic adhesive 12 is provided above and below in FIG. The adhesive injection port 16 is formed. Opening 14
Has a diameter d2 (for example, 0.7 when viewed in the transmission direction of the optical signal).
mm) circular shape, and determines the light transmission region 2 of the Faraday rotators 1, 1 ′. Also, the adhesive injection port 16
Is a circular shape having a diameter d3 (for example, 0.7 mm).

The optical component 28 in which the three Faraday rotators 1, 1'are superposed is adapted to rotate the deflection direction of the incident light by a predetermined angle, and is used for a variable optical attenuator or the like.

Next, a method of manufacturing the optical element and the optical component including the same according to the present embodiment will be briefly described. First, a Bi-substituted magnetic garnet single crystal film is formed on a wafer having a diameter of 2 inches, for example, by the LPE method. Next, the wafer is 11 mm × 11 mm (11 mm square)
Divide into, and then attach to a glass substrate etc.
Incisions are made using a 25 mm rotating blade to form grooves 4, 5. Next, the same rotary blade is used to divide into 1 mm × 1 mm (1 mm square). Next, each Faraday rotator 1 is separated from the glass substrate using ethanol or the like.

Next, a plurality of Faraday rotators 1, 1'are superposed. FIG. 6 shows a configuration when the Faraday rotators 1 and 1 ′ are superposed on each other. As shown in FIG.
The Faraday rotator 1 has an adjacent Faraday rotator 1,
It is arranged so that the groove portions 4 and 5 face 1 '. Next, the plurality of superposed Faraday rotators 1, 1 ′ are placed at predetermined positions in the holding member 10.

Next, using a dispenser, the holding member 1
The ultraviolet curable organic adhesive 12 is injected from one adhesive injection port 16 of No. 0, and is applied to one end side 7 side of the overlapped Faraday rotator 1. Next, the organic adhesive 12 is cured by irradiating it with ultraviolet rays, for example, for 30 seconds. Then, similarly, the organic adhesive 12 is applied to the other end portion 6 side and irradiated with ultraviolet rays to cure the organic adhesive 12. Through the steps described above, the optical component 28 including the Faraday rotator 1 according to the present embodiment is completed.

FIG. 7 shows the effect when the optical element according to the present embodiment and the optical component including the same are used.
The horizontal axis represents the presence or absence of the groove portions 4 and 5, and the vertical axis represents the ratio (adhesion failure rate (%)) in which the organic adhesive 12 penetrates to the light transmission region 2 to cause adhesion failure. As shown in FIG. 7, the conventional optical component having no grooves 4 and 5 has a poor adhesion rate of about 34%, whereas the optical component according to the present embodiment having the grooves 4 and 5 has a poor adhesion. The rate is about 0.5%. As described above, according to the optical element of the present embodiment, since the adhesive hardly penetrates into the light transmitting region 2 when assembling the optical component, the manufacturing yield is significantly improved.

The grooves 4 and 5 can be formed in the step of cutting the Faraday rotator 1 having a size of 1 mm by using the same rotary blade used for the cutting. For this reason, the process is slightly lengthened, but no new process or member is required. Therefore, the manufacturing cost hardly increases.

Next, a modified example of an optical component using the optical element according to this embodiment will be described with reference to FIG. FIG. 8 shows a modification of the configuration of the optical component using the optical element according to this embodiment. In this modification, the optical isolator 20 is used as an optical component. As shown in FIG. 8, the optical isolator 20 is composed of two wedge-shaped TiO ₂ rutile plates 18 and a Faraday rotator 1 sandwiched between them and stacked. The Faraday rotator 1 has grooves 4 and 5 formed so as to face the wedge-shaped TiO ₂ rutile plate 18. According to this modification, the same effect as the above can be obtained.

FIG. 9 shows another modification of the configuration of the optical component using the optical element according to this embodiment. As shown in FIG. 9, the optical isolator 2 used in this modification
0'is different from the optical isolator 20 shown in FIG. 8 in that the grooves 4 and 5 are formed on the _two wedge-shaped TiO ₂ rutile plates 18 side. Since it is optional which side the groove portions 4 and 5 are formed on, it is possible to form the groove portions 4 and 5 on the side of a material which is easy to form,
The material price may be lower. According to this modification, the same effect as the above can be obtained.

The present invention is not limited to the above embodiment, but various modifications can be made. For example, in the above-described embodiment, the grooves 4 and 5 are formed in a straight line substantially parallel to the edge portions 6 and 7 to which the organic adhesive is applied, but the present invention is not limited to this, and the groove 4 and 5 may have a curved shape, or a plurality of grooves 4 and 5 may be formed.

In the above embodiment, the grooves 4 and 5 are formed in the vicinity of the two end sides 7 and 8 of the Faraday rotator 1, but the present invention is not limited to this. For example, when the Faraday rotator 1 is fixed to the holding member 10 by applying the organic adhesive to only one edge portion 7 or 8, the edge portion 7 is
Alternatively, the grooves 4 or 5 may be formed only in the vicinity of 8.

Further, in the above embodiment, the optical element and
Faraday rotator 1 and TiO ₂Example of rutile plate 18
However, the present invention is not limited to this, and a quartz plate or LiNb
O₃(Lithium niobate) plate, gas with dielectric multilayer film
It can also be applied to lath boards.

Further, in the above-mentioned embodiment, the cross sections of the grooves 4 and 5 are "U" shaped, but the present invention is not limited to this, and for example, "U" shaped or "V" shaped. It may have other shapes such as.

[0037]

As described above, according to the present invention, it is possible to realize an optical element having a small size and excellent optical characteristics and an optical component including the same, without increasing the manufacturing cost.

[Brief description of drawings]

FIG. 1 is a diagram showing a basic configuration of the present invention.

FIG. 2 is a diagram showing a configuration of an optical element according to an embodiment of the present invention.

FIG. 3 is a sectional view showing a configuration of an optical element according to an embodiment of the present invention.

FIG. 4 is a perspective view showing a configuration of an optical component according to an embodiment of the present invention.

FIG. 5 is a diagram showing a configuration of an optical component according to an embodiment of the present invention.

FIG. 6 is a diagram showing a manufacturing process of the optical component according to the embodiment of the present invention.

FIG. 7 is a diagram showing effects of an optical element and an optical component including the same according to an embodiment of the present invention.

FIG. 8 is a diagram showing a modification of the configuration of the optical component according to the embodiment of the invention.

FIG. 9 is a diagram showing another modification of the configuration of the optical component according to the embodiment of the invention.

FIG. 10 is a diagram showing a conventional optical component having poor penetration.

[Explanation of symbols]

1, 1'Faraday rotator 2 Light transmission region 4, 5 Grooves 6, 7 Edges 10 Holding member 12 Organic adhesive 14 Opening 16 Adhesive injection port 18, 18 'Wedge type TiO ₂ rutile plate 20, 20 '' Optical isolator 21 Optical element 28 Optical component

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Claims (3)

[Claims] 1. A light transmitting region through which light is transmitted, an edge portion to which an adhesive is applied when it is fixed to a holding member by being overlapped with another element in the light transmitting direction, and the adhesive. In order to prevent the light from penetrating into the light transmitting region, an optical element having a groove formed in the vicinity of the edge portion so as to face the other element. 2. The optical element according to claim 1, wherein the groove portion is formed substantially parallel to the end side portion. 3. An optical component having an optical element that is stacked in a light transmitting direction and a holding member that holds the optical element, wherein the optical element is the optical element according to claim 1 or 2. An optical component comprising: