JP2003262829A - Flush type optical component and flush type optical isolator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flush type optical component having a high performance. <P>SOLUTION: The flush type optical component, which is provided with an optical element, an optical fiber and a groove in which the optical element is buried across the fiber, is characterized in that the side face on the incident light side among cross sections which are parallel to the optical fiber of the groove is inclined at an angle toward the groove depth direction which is larger than that toward the side face on the emitting side. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical component and an optical isolator used in optical communication and optical measurement.

[0002]

2. Description of the Related Art It is known that a semiconductor laser used as a light source of various optical systems has unstable oscillation due to reflected return light from an optical system coupled thereto.
Isolators are used to prevent this. With the rapid expansion of optical communication systems in recent years, there is an increasing demand for miniaturization and cost reduction of isolators.

FIG. 1 shows the structure of a conventional basic isolator.
Shown in. Polarizers 10a on both sides of the Faraday rotator 11,
10b is a configuration in which a magnet 12 for magnetizing the Faraday rotator is arranged around the optical fiber 8a, 8b.
Two condensing lenses 9a and 9b are required between and.
With this configuration, light incident in the forward direction (arrow direction of C in the drawing) is transmitted and light entering in the reverse direction (arrow direction of D in the drawing) is blocked, so that the function as an isolator is realized. However, many optical elements are required, and the overall configuration becomes large.

On the other hand, a method based on a simple method rather than such a complicated method is described in JP-A-3-63606 and JP-A-4-307512.

This method is called "embedding type", in which the embedded optical fiber is fixed to the substrate with a resin, a groove portion is formed across the optical fiber portion by a dicing saw or the like, and the element is embedded and fixed by embedding. It is made. According to this, there is an advantage that the optical axis alignment is not required for manufacturing the optical isolator and the manufacturing is significantly facilitated. However, on the other hand, when the light output from the optical fiber passes through the element portion, diffraction occurs, which causes a problem that the thickness of the element becomes a neck and the insertion loss increases. On the other hand, a method such as enlarging the core of the optical fiber by local heating to reduce the diffractive power is taken.

[0006]

[Patent Document 1] Japanese Patent Laid-Open No. 3-63606

[Patent Document 2] Japanese Patent Laid-Open No. 4-307512

[0007]

Since the embedded optical isolator using polarizing glass is a polarization dependent type, when it is used for an LD module, it is necessary to adjust the polarization direction of the incident light at the time of insertion. It was If equipment and man-hours for performing this adjustment are required, the LD module assembly cost increases. Also, with ink, laser marker, etc.,
There is also a method of displaying the incident plane position, but it is difficult to perform accurate incident polarization plane alignment because both the marking accuracy and the placement positioning accuracy are low because the parts are small.

Further, in the case of a general optical isolator, in order to remove the incident light and the return light reflected at the interface of the optical element, or to cancel the principle deviation of the incident and outgoing positions of the light, the element is aligned with the optical axis. Although the method of inclining the surface is taken, this embedded optical isolator has a problem that the optical connection loss is deteriorated by making the rectangular groove processed portion which is the element insertion portion oblique.
This is because it is necessary to make the element arrangement groove portion oblique in order to reduce the reflected return light, but if the oblique angle is increased, the connection loss also increases. Therefore, it is necessary to obtain the reflection attenuation amount and the connection loss required in the design and perform the groove processing with high accuracy.

However, when grooving cutting is performed using a diamond blade, the blade is likely to be shaken when the blade hits the workpiece (ferrule) and when the blade comes out of the workpiece. This causes a problem that the groove shape of the workpiece becomes a trapezoidal shape (upward wide) (the surface to be processed is wide due to the influence of the wobble of the whetstone and becomes narrower in the depth direction (similar to the width of the whetstone)). Further, the side surface of the rectangular groove that becomes the light entrance and exit surface, the surface roughness is large in the cut surface cut by the diamond blade, so it is easy for microscopic bubbles to enter between the adhesive and the cut surface when embedding and bonding the optical element, This may cause loss and reflection, and the side surface of the rectangular groove may be mirror-finished. As a method of mirror-finishing the cut side surface, there is a method called float slice. For cutting wheels and workpieces,
While applying a polishing liquid (cerium oxide, colloidal silica, etc.), cutting and polishing are performed simultaneously. However, when this processing is performed, the groove upper part where a large amount of the polishing liquid is applied becomes wide, and the processing side surface sag becomes larger than the above-mentioned diamond blade cutting. Since the groove formed in this state is different from the predetermined shape, the return loss and the connection loss may be deteriorated.

This will be explained by a processing method 1 shown in FIGS. 2 (a) and 2 (b) below, as shown by the upper surface of the interface angle of the optical element embedding groove 23 of the ferrule 20 supporting the optical fiber 21. Even if the groove is machined at a predetermined inclination angle, the trapezoidal angles θ1 and θ2 (usually θ1 = θ2) caused by the machining deviation are added so that it can be seen from the groove state on the side surface, and the angle becomes larger than the design inclination angle. The connection loss will increase.

[0011]

In order to solve the above problems, the present invention provides an optical component having an optical element, an optical fiber, and an embedding groove for embedding the optical element across the optical fiber. Provided is an optical component in which a side surface on an incident light side of a cross section of the embedded groove parallel to the optical fiber is inclined to a groove depth direction more than a side surface on an emission side. The embedded groove may be formed by a mechanical processing method or a mechanical processing method and a chemical polishing processing method. The optical element may be an optical isolator element including a polarizer and a Faraday rotator. According to the present invention, the groove shape becomes a trapezoidal shape (upper wide), and the groove formed in this state is different from the predetermined setting shape, so that the return loss and the connection loss are deteriorated. This can be solved by the fact that the side surface on the light incident side of the optical element embedding groove provided in the ferrule capillary is inclined more largely than the side surface on the emission side with respect to the groove depth direction.

The present invention also provides a composite of a rectangular groove in which an optical element having a polarizer and a Faraday rotator is arranged, and a permanent magnet having a reference side substantially parallel to one surface of the rectangular groove,
A ferrule having an embedded groove for holding an optical fiber and embedding at least a part of the composite of the optical element and the permanent magnet across the optical fiber, and at least the composite of the composite and the ferrule. An optical isolator, comprising: a substrate having a rectangular holding groove that fills at least a part having a flat surface that supports the reference side. Here, preferably, one surface of the optical element and at least one surface forming the rectangular groove are substantially parallel to and in close contact with each other. Also, preferably, at least one surface of the composite and at least one surface forming the rectangular holding groove are substantially parallel to and in close contact with each other. Preferably, both the optical element and the composite have a rectangular parallelepiped shape.
Preferably, the light incident side surface of the embedded groove is inclined with respect to the groove depth direction.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION (1) The groove shape described above is a trapezoidal shape (upper wide), and the groove formed in this state is different from the predetermined setting shape, so the reflection attenuation With respect to the problem that the amount and the connection loss are deteriorated, the present invention provides that, in the embedded optical isolator, the side surface on the light incident side of the optical element embedded groove provided in the ferrule capillary is inclined with respect to the groove depth direction. The problem is solved by an embedded optical isolator characterized by. (2) In another embodiment, the incident polarization plane of the polarizing glass optical element used for the embedded optical isolator forms a predetermined angle with respect to the reference side of the element shape, and the embedded optical isolator is configured. Ferrule, magnet, reference surface member (L
(For D etc.), in order to transmit the reference side angle of the optical element using the polarizing glass to the reference surface member, a rectangular groove is formed substantially parallel to the magnet reference side using a rectangular magnet,
An optical element is formed in this groove. As a result, the embedded optical isolator with a predetermined incident polarization direction can be obtained by positioning the magnet reference side on the holder surface of the reference member.
More specifically, the present invention provides an optical element constituted by a polarizing glass and a Faraday rotator, in the embedding groove of a ferrule capillary having an embedding groove for holding an optical fiber and embedding the optical element, In an embedded optical isolator fixed to the optical fiber in alignment with a permanent magnet for applying a magnetic field to the Faraday rotator around the optical element, the optical element has a rectangular parallelepiped shape (including a cube). A rectangular groove that allows the reference side of the optical element to be inserted and positioned in the permanent magnet, and a reference side that is substantially parallel to the bottom of the rectangular groove, and the reference side of the optical element is the permanent magnet. What is inserted and fixed in the rectangular groove of, is inserted and fixed in the embedded groove of the ferrule capillary,
The permanent member in which the reference side of the optical element is inserted and fixed in the holding groove of the holder member having the rectangular holding groove that allows the insertion position of the permanent magnet and the reference holder surface substantially parallel to the bottom of the holding groove. A polarization dependent embedded optical isolator is provided by inserting and fixing the reference side of the magnet into the holding groove.

(3) In another embodiment, a ferrule capillary in which a groove is formed for inserting an optical element at a predetermined position with respect to a reference substrate, and a groove bottom side of the ferrule capillary and an element reference side are positioned and bonded and fixed. I do. More specifically, the present invention provides an optical element constituted by a polarizing glass and a Faraday rotator, in an embedding groove of a ferrule capillary having an embedding groove for holding an optical fiber and embedding the optical element. , In an embedded optical isolator fixed in alignment with the optical fiber and arranging a permanent magnet for applying a magnetic field to the Faraday rotator around the optical element, a ferrule capillary to which the optical fiber is bonded and fixed in advance. Adhesively fixed in place on the board,
With reference to the substrate surface, a rectangular groove for inserting the optical element is formed at a predetermined position and an angle in the ferrule capillary to form the optical element into a rectangular parallelepiped shape, and the reference side of the optical element is the ferrule. Provided is a polarization-dependent embedded optical isolator characterized in that a predetermined incident polarization direction is obtained with respect to a bottom surface of a substrate by abutting and inserting the bottom surface of a groove of a capillary for positioning. In this case, the optical element formed in a rectangular parallelepiped shape is fixed to a rectangular groove of a magnet, and this is inserted into the rectangular groove of the ferrule capillary, and the reference side of the optical element or a predetermined relationship with it is used. The reference plane of the set magnet is
A predetermined incident polarization direction may be set to the bottom surface of the substrate by abutting and inserting the bottom surface of the groove of the ferrule capillary to position it. According to this form, in addition to precisely adjusting the incident polarization direction,
The optical isolator can be easily assembled, and an inexpensive material such as a glass plate can be used for the reference base, resulting in a very low price.

(4) In another embodiment, the polarization dependent embedded optical isolator has a metal fine particle distribution layer on the surface and an incident polarization plane is oriented at a predetermined angle with respect to a reference side. 1
Polarizing glass, a Faraday rotator having a rotation angle of about 45 °, and a metal fine particle distribution layer on the surface, and the polarization plane is oriented at about 45 ° with respect to the first polarizing glass. A second polarizing glass is laminated and adhered so that the metal fine particle distribution layer faces the Faraday rotator to form a laminated body, and the first and second polarizing glasses are formed on both the incident side and the emitting side of the metal fine particles. Polishing up to the front of the distribution layer, dicing the polished laminated body into a predetermined rectangular parallelepiped with respect to its reference side, and thus magnetizing the thus obtained thin rectangular parallelepiped element in a predetermined direction. It is manufactured by embedding it in the groove of a magnet. (5) In another embodiment, the polarization dependent embedded optical isolator has a first fine particle distribution layer having metal fine particle distribution layers on both surfaces and an incident polarization plane oriented at a predetermined angle with respect to a reference side. The polarizing glass, the Faraday rotator having a rotation angle of about 45 °, and the metal fine particle distribution layer on both surfaces,
The second polarizing glass whose polarization plane is oriented at approximately 45 ° with respect to the polarizing glass of is alternately laminated and adhered many times,
The laminated body is cut at a predetermined interval in the laminating direction, the obtained optical element array is inserted into and bonded to the groove of the permanent magnet, and an intermediate portion between both metal fine particle distribution layers of each of the first and second polarizing glasses. Is cut together with the permanent magnet.

(6) In still another embodiment, the polarization dependent buried optical isolator has metal fine particle distribution layers on both surfaces and the incident polarization plane is oriented at a predetermined angle with respect to the reference side. The first polarizing glass, the Faraday rotator having a rotation angle of about 45 °, and the metal fine particle distribution layer on both surfaces, and the first polarizing glass is about 45 °.
And a second polarizing glass having a polarizing surface facing each other are alternately laminated and bonded a number of times to form a laminated body, and the laminated body is cut at a predetermined interval in the laminating direction to obtain an optical element array, The permanent magnet having a large number of grooves formed at regular intervals is inserted and adhered to the grooves, and the intermediate portion between the two distribution layers of each of the first and second polarizing glasses is cut off together with the permanent magnet, Inserting and fixing a rod-shaped magnet having a plurality of optical elements including a second polarizing glass and a Faraday rotator into a groove formed in a plurality of ferrules in which optical fibers are embedded, and then cutting the rod-shaped magnet between the ferrules. Manufactured by.

[0017]

EXAMPLE A constitution of the present invention capable of reducing light reflection is illustrated in FIG. Here, the same reference numerals as those in FIG. 2 are used. In this case, as shown in (a), the groove is processed at a certain angle to escape the reflected light with respect to the optical axis direction to form the rectangular groove 23, but as shown in the side surface of (b). By inclining the processing grindstone by an angle θα, the angle on the incident side with respect to the perpendicular of the rectangular groove 23 is made larger than the angle on the emitting side. However, there is a problem that the end face reflected light which is prevented by providing a predetermined inclination with respect to the optical axis increases the returned light as the end face inclination becomes smaller, but the angle on the incident side (LD side) of the embedded optical isolator is By adopting the configuration of the present invention in which the groove is processed to be large, it becomes an embedded optical isolator with good return loss and junction loss (because reflection on the output side is blocked by the optical isolator). .

The above embodiment according to the present invention is specifically described in the structure of a specific optical isolator described below.
Also, it should be understood that it can be realized in the manufacturing process.

In order to facilitate the assembling work in an LD (laser device) manufacturer using an optical isolator, the LD
It is intended to provide an optical element-embedded optical isolator in which an optical isolator with a reference base member is simply mounted on the stem surface and package surface of a module and does not require incident polarization direction alignment. A rectangular parallelepiped magnet, a rectangular parallelepiped optical element, and rectangular grooves for aligning sides are machined to facilitate the alignment of the incident polarization plane with the surface of the base member, and the angles are accurately obtained by butting. By covering the grooved portion of the embedded optical isolator with a member, the effects of structural reinforcement and reliability improvement can be obtained.

An optical element using two polarizing glasses and a Faraday rotator is used as the optical element. In this case, the polarizing glass has metal fine particle distribution portions (about 50 μm) provided on both sides, and preferably, it is cut at the middle portion of both sides or left on one side and lapped or polished on the other side. , Make a thin optical element. A low loss optical fiber embedded optical isolator can be realized by using thin elements. That is, in a thick element, the transmission loss increases due to the diffraction and scattering of light, but by making the element thin, the diffraction and scattering of light can be reduced and the loss can be reduced.

Since a large number of laps and polishing steps are required for shaving one side of expensive polarizing glass, the unfunctional portion of the polarizing glass is left as a margin for cutting, and if a grindstone with a relatively fine grain size is used for cutting, one sheet of polarized light is obtained. Two pieces can be removed from the glass, and the lapping and polishing steps can be omitted. However, in order to realize this, as a method of making the cut surface roughness close to a mirror surface, 1) a method of passing a blade having a fine diamond particle size after cutting with a blade having a relatively rough particle size, or a T-shaped grindstone (side surface processing is possible) There is a method of performing side feed using a grindstone or a cup grindstone), and 2) a method of cutting while applying an oxidized cerium, colloidal silica or the like to a workpiece.

In a preferred structure of the embedded optical isolator of the present invention, the optical element used is composed of a polarizing glass and a Faraday rotator, the support holding the optical fiber is a ferrule capillary, and the Faraday rotator. There is a rectangular groove in which a rectangular parallelepiped (including cubic) element can be inserted and positioned in a permanent magnet that applies a magnetic field, and the bottom of this groove is almost parallel to the reference side of the magnet,
An optical fiber is inserted and fixed in a ferrule capillary, and an optical element is placed in a predetermined position. A rectangular groove is formed in a holder member in which a magnet is embedded.
The reference side of the inserted and bonded optical element inserted magnet is arranged. The bottom of the rectangular groove of the holder member is a positioning groove bottom with respect to the magnet reference side, and the surface of the holder member formed parallel to the surface of this groove bottom is positioned and held by the holding surface on the LD side. It is a polarization-dependent embedded optical isolator characterized by serving as a reference holding surface. Thus, the incident polarization plane of the polarizing glass optical element used for the embedded optical isolator makes a predetermined angle with respect to the reference side of the element shape, and the ferrule, magnet, and reference that form the embedded optical isolator are formed. For face members,
In order to transmit the reference side angle of the optical element using the polarizing glass to the reference surface member, a rectangular magnet is used to form a rectangular groove substantially parallel to the magnet reference side, and the optical element is formed in this groove. As a result, an embedded optical isolator having a predetermined incident polarization direction with respect to the reference member surface can be obtained.

Manufacturing Example 1 A first manufacturing example of the present invention will be described with reference to FIG. The polarization-dependent optical isolator using polarizing glass is
When used for the D module, it was necessary to adjust the polarization direction of the incident light at the time of insertion. This new embedded optical isolator has a structure that does not require troublesome direction alignment when assembling the module, and by using a new manufacturing method, highly accurate polarization direction alignment, mass production, and cost reduction can be achieved. It will be possible. FIG. 4 shows a standard construction method. As shown in FIG. 4 (a), the polarizing glass 1 whose incident polarization plane is perpendicular or parallel to the reference side (depending on the design) and the rotation angle Of the Faraday rotator 3 whose angle is about 45 °, and the polarizing glass 2 whose polarization plane is oriented at about 45 ° with respect to the reference plane. These are base plates having a size capable of taking a large number of optical elements.

As shown in FIG. 4B, these base plates 1, 2,
3 is mounted on a peak wavelength measuring instrument having a magnet 34 for magnetically saturating the Faraday rotator, and the mutual angular relationship is determined. That is, the light from the LED light source 30 is applied to the collimator 3
1 to the base plates 2, 3 and 1 in the reverse direction, and the optical sensor 3
Then, the optical power meter 33 measures the optical power. While the polarizing glass 1 and the Faraday rotator 3 are fixed, the polarizing glass 2 is rotated and the angle at which the maximum isolation is obtained is determined. In this way, the base plate is adjusted in advance so that the maximum isolation is obtained at a predetermined wavelength. Next, each of the base plates is adhered and fixed with an optical adhesive in a predetermined configuration. As shown in FIG. 4C, the polarizing glasses 1, 2
On both the incident side and the outgoing side are polished to the front of the metal fine particle (Ag) distribution layer (about 60 μm). In this way, it becomes possible to manufacture a thin element (for example, a thickness of 0.3 mm to 0.5 mm).

As shown in FIG. 4D, dicing is then performed using a diamond grindstone to cut out a large number of optical elements (for example, 0.3 mm × 0.4 mm). Figure 4
(E) shows the obtained optical element 5, R1 is a reference side thereof, and has a constant angular relationship with the polarizing glasses 1 and 2. As shown in FIG. 4 (f), the optical element 5 is attached to the permanent magnet 6.
A rectangular groove is formed for the insertion and positioning of. The dimensions of the magnet are, for example, 2.0 mm × 1.0 mm × (thickness 0.3 to
0.5) mm. The length of the groove 23 is equal to the thickness t of the optical element 5. By forming the bottom of the groove 23 and the reference side R2 substantially parallel to each other, the two have a constant relationship. After grooving,
The magnet is magnetized in a predetermined manner.

Next, as shown in FIG. 4G, the reference side R1 of the optical element 5 is inserted into the rectangular groove 23 of the magnet in a predetermined direction and fixed by adhesion. As a result, the reference side R1 of the optical element 5 having a predetermined angle with respect to the polarization angle of the polarizing glass is the reference side R of the magnet.
It is defined to have a constant angular relationship with respect to 2. As shown in FIG. 4H, the TEC optical fiber 21 is adhered to the ferrule capillary 7, the end face of the ferrule is PC-polished, and the fiber is cut. A groove for inserting an element and a magnet is formed at a predetermined portion (optical fiber core enlarged portion) of the ferrule to which the TEC optical fiber is bonded to form a rectangular groove 37. The groove is formed at a predetermined angle so that the reflection between the optical fiber and the element is reduced.

Rectangular magnet 6 with an optical element inserted into the groove 37 of the grooved TEC optical fiber ferrule capillary 7
The reference side R2 is inserted and fixed by adhesion. The adhesive used is one that has a small refractive index adjustment and a small transmission loss so that the light on the optical path is less reflected and absorbed. In this way, the embedded optical isolator is completed. As shown in FIG. 4 (i), a reference base member 40 for fixing the embedded optical isolator at a predetermined position is used. The base member is provided with a groove 39 for abutting the rectangular magnet.
Is parallel to the reference plane R3 which is the bottom of the base member 40. Next, as shown in FIG. 4J, the embedded optical isolator 38 obtained in the above step is inserted and bonded and fixed to the base member 40. In this way, the embedded optical isolator has a predetermined incident polarization direction with respect to the reference plane R3 (bottom surface of the base member).

Manufacturing Example 2 A method of manufacturing an embedded optical isolator according to the second manufacturing example of the present invention will be described with reference to FIG. This example shows a method of high mass production. First, the polarizing glass 1 whose incident polarization plane is perpendicular or parallel to the reference side (depending on the design), the Faraday rotator whose rotation angle is about 45 °, and about 45 ° relative to the reference plane A polarizing glass 2 having a polarizing plane is used. The above-mentioned element is the one in which the angle is adjusted in advance so that the maximum isolation is obtained at a predetermined wavelength as shown in FIGS. 5A to 5C, which are the same steps as FIGS. 4A to 4C. As shown in FIG. 5C, each element is cut along the cutting lines 41, 42, 43 into a number of strip-shaped cutting pieces (cutting element width: 0.3 mm, depending on the element size in the longitudinal direction, it is 10 mm. ).

Then, as shown in FIGS. 5C to 5D, polarizing glass 0 ° -Faraday rotator-polarizing glass 45 °-
The Faraday rotator is repeatedly stacked in the order of the Faraday rotators and bonded and fixed. At this time, the respective elements are aligned and adhered while abutting against the reference surface of the jig so that the relative adhesion angles of the respective elements are not displaced. As shown in FIG. 5D, the optical element array adhesive plate is then cut into strips (element width 0.4 mm) in a direction orthogonal to the element arrangement direction. The obtained strip array optical element 45 is shown in FIG. As shown in FIG. 5 (f), a groove 6 having a width of 0.45 and a depth of 0.35 mm is formed on the elongated magnet 6 having a rectangular parallelepiped shape. Next, as shown in FIG. 5G, the strip array optical element 45 is inserted into the magnet groove 23 and fixed by adhesion. Figure 5 (h)
As described above, the center of the polarizing glass plate of the optical element to which the magnet has been bonded is used as a cutting margin, and the optical element is cut along the cutting line 46. However, the Ag metal fine particle distribution portion is not scraped (the cutting margin is about 0.35 mm).

After that, steps corresponding to FIGS. 4H, 4I, and 5J are performed according to FIGS. 5I, 5J, and 5K to obtain a finished product. The steps are summarized below.・ In the direction that the magnetic application condition is appropriate for the element configuration,
Magnetize and bond the TEC optical fiber to the ferrule,
The end surface of the ferrule is PC-polished, and the fiber is cut.・ Tec optical fiber adhesive ferrule Capillary groove (for expanding the optical fiber core) is inserted at a specified location (optical fiber core expansion part) to form a groove for inserting a magnet (the groove is formed at a specified angle so that the reflection of the optical fiber and the element is reduced). .・ Insert and fix the magnet integrated optical element into the grooved TEC optical fiber ferrule capillary (Adhesive used at this time adjusts the refractive index and reduces the transmission loss so that the light on the optical path is less reflected and absorbed. Use one). Use a reference base member for fixing the embedded optical isolator in place (this base member has a groove for abutting the rectangular magnet, and this groove is parallel to the bottom surface of the base member).・ Insert and fix the embedded optical isolator and the base member. -It is an embedded optical isolator that has a predetermined incident polarization direction with respect to the reference plane (bottom surface of the base member).

Manufacturing Example 3 FIGS. 6 to 7 show a manufacturing process of an optical isolator by the embedded optical isolator array method according to another manufacturing example of the present invention. In this example, first, the steps of FIGS. 6A to 6E are performed. These steps are the same as those shown in FIGS. However, in this manufacturing example, the optical element array is used as an array without being separated into individual optical elements. The steps up to this point are summarized as follows. -Polarizing glass 1 whose incident polarization plane is perpendicular or parallel to the reference side (depending on the design) and the rotation angle is about 4
A Faraday rotator 3 having an angle of 5 ° and a polarizing glass 2 having a polarization plane oriented at approximately 45 ° with respect to the reference plane are used (step (a)). The angle of the above element is adjusted in advance so that the maximum isolation is obtained at a predetermined wavelength (step (b)).・ Cut each into strips (Cutting element width: 0.3 m
m and 10 mm depending on the size of the element in the initial direction in the longitudinal direction) (step (c)).・ Polarizing glass 0 ° -Faraday rotator-Polarizing glass 45
° -Repeat the Faraday rotator in this order repeatedly and stack and bond them together. At this time, the respective elements are aligned and adhered while abutting against the reference surface so that the relative adhesion angles of the respective elements are not displaced (steps (c) to (d)). The optical element array 4 is obtained by cutting the optical element array adhesive plate into strips (element width 0.4 mm) in a direction perpendicular to the element arrangement direction.
5 (steps (d) to (e)).

On the other hand, as shown in FIG. 6 (f), a large number of grooves having a width of 0.45 and a depth of 0.35 mm are machined on the elongated rectangular magnet 6 at a predetermined pitch (2 mm). Figure 6 (g)
As described above, a large number of pieces are inserted and fixed in the magnet groove 23 in accordance with the reference plane R1 of the strip array optical element 45. Magnet groove 2
The bottom surface of 3 is parallel to the reference plane R2 of the magnet (in this example, the optical element insertion side). As shown in FIG. 6 (h), the center of the polarizing glass plate of the optical element to which the magnet has been adhered is cut off (however,
Do not scrape the Ag distribution section. For example, the cutting margin is 0.35m
m) By cutting along the cutting line 47, the individual optical element arrays 50 integrated with magnets are cut off.
The obtained magnet-integrated optical element array 50 is shown in FIG. The magnets 6 of this array are magnetized in a direction that provides a suitable magnetic application condition for the element configuration.

Moving to the step of FIG. 7 (j), the TEC optical fiber 21 is adhered to each ferrule capillary 7,
The end face of the ferrule is PC polished and fiber cut. The ferrule capillary 7 obtained is temporarily fixed to the jig 4.
The TEC optical fiber 21 is temporarily fixed to the ferrule fixing groove 48 of FIG. 9 and the rectangular groove 23 for inserting the element bonded magnet is formed at a predetermined position (optical fiber core enlarged portion) of the ferrule capillary 7 to which the TEC optical fiber 21 has been bonded (groove). The processing makes a certain angle so that the reflection of the optical fiber and the element is reduced).
Groove processing at this time is performed simultaneously by arranging a large number of TEC optical fiber adhesive ferrule capillaries at a predetermined pitch and location.

In the process of FIG. 7 (k), groove-finished T
The magnet-integrated optical element array 50 (FIG. 6 (i)) is inserted into the EC optical fiber ferrule array and adhered and fixed. The adhesive used is one that has a small refractive index adjustment and a small transmission loss so that the light on the optical path is less reflected and absorbed. In FIG. 7 (l), the magnets 6 of the embedded optical isolator array arranged at a predetermined pitch are cut between the ferrules and removed from the jig. As a result, a large number of magnets with optical isolators can be obtained. The adhesive and the like are peeled off from the temporary fixing jig and removed by washing (a hot melt type wax is used for temporary fixing of the embedded optical isolator to the temporary fixing jig). Separately, as shown in FIG. 7 (m), the embedded optical isolator is set at a predetermined position by using the reference base member 40 similar to that described in FIGS. 4 (i) to (j). (This base member is provided with a groove portion that abuts the reference surface R2 of the rectangular magnet, and the bottom surface of this groove is parallel to the reference surface R3 which is the bottom surface of the base member). Then, the embedded optical isolator and the base member are inserted and bonded and fixed. FIG. 7 (n) is an optical isolator unit with an optical fiber having an embedded optical isolator having a predetermined incident polarization direction with respect to the reference plane R3 (bottom surface of the base member).

FIG. 8 shows a practical example incorporated in the LD module of each manufacturing example. The LD module includes a ceramic substrate 51, an LD chip 55 supported by a stem 52 with a Si-V groove and a monitor PD 54 arranged on a reference surface of the substrate, and a lead frame 57 attached to the back surface of the substrate 51, and these are mounted on an epoxy resin. It is housed in a transfer mold 53 made of resin and fixed with a transparent mold resin 56. In the embedded optical isolator of the present invention, the reference surface R3 of the holder member is fixed to the reference surface of the substrate 51 as shown in the figure. It was done. Therefore, the reference side (plane) R1 of the optical element, the reference side (plane) R2 of the magnet, and the reference plane R3 of the holder member are parallel to each other, and the polarization planes of the polarizing glasses 1 and 2 have a fixed relationship with the LD module. Becomes

Manufacturing Example 4 FIGS. 9 to 10 show a manufacturing process of an optical isolator by the embedded optical fiber array method according to still another manufacturing example.
In this example, an inexpensive glass substrate is used as the holding substrate, the ferrule capillary is permanently fixed to it, and the reference surface of this glass substrate and the reference surface (side) of the optical element (the one to which the polarizing plate and the Faraday rotator are bonded) (In the magnet-integrated optical element, the reference surface (side) of the magnet) is fixed in a predetermined relationship, so that the optical isolator can be easily assembled. In this example, first, an array in which a plurality of optical elements are embedded in a magnet is manufactured by the steps shown in FIGS. Since this step is the same as the steps (a) to (i) in FIGS. 6 to 7, refer to Manufacturing Example 3 for details. The steps up to this point are summarized as follows. -Polarizing glass 1 whose incident polarization plane is perpendicular or parallel to the reference side (depending on the design), Faraday rotator 3 whose rotation angle is approximately 45 °, and approximately 45 to the reference plane A polarizing glass 2 having a polarization plane facing at 0 is used (step (a)). The angle of the above element is adjusted in advance so that the maximum isolation is obtained at a predetermined wavelength (step (b)).・ Cut each into strips (cutting element width: 0.3 mm,
It is set to 10 mm although it depends on the size of the element in the longitudinal direction (step (c)).・ Polarizing glass 0 ° -Faraday rotator-Polarizing glass 4
A large number of 5 ° -Faraday rotators are repeatedly stacked and bonded and fixed (steps (c) to (d)). At this time, the respective elements are aligned and adhered while abutting against the reference surface so that the relative adhesion angles of the respective elements are not displaced. The optical element array adhesive plate is cut into strips (element width 0.4 mm) in a direction perpendicular to the element array direction to form the optical element array 45 (steps (d) to (e)). A large number of grooves having a width of 0.45 and a depth of 0.35 mm are machined into the cubic magnet 6 at a predetermined pitch (3 mm) (step (f)). -A large number of strip array optical elements 45 are inserted in the magnet groove portion 23 so as to be aligned with the reference surface and adhesively fixed (step (g)). -Cutting is performed so that the center of the polarizing glass plate of the optical element with the magnet attached becomes the cutting margin (however, the Ag distribution portion is not shaved: the cutting margin this time was 0.35 mm) (step (h )). The magnet 6 is magnetized in the direction in which the magnetic application condition is appropriate for the element configuration (step (i)).

Apart from the magnet-integrated optical element array 50, in steps (j) to (l) of FIG. 10, an array in which a large number of optical fiber ferrules are fixed to a glass substrate is prepared.
That is, first, in the step (j) of FIG.
Using, a rectangular groove 54 (or V groove) for arranging the ferrule at a predetermined position is formed on the glass substrate 52 (other stable inorganic materials may be used). Then, in step (k) of FIG.
The end surface of the ferrule capillary 7 in which the EC optical fiber 21 is embedded and adhered is PC-polished to cut the fiber. Arrange these ferrules at the predetermined positions in the groove 54,
An optical fiber array is made by fixing with an adhesive.
Next, as shown in FIG. 10 (l), the reference surface R3 of the glass substrate 52 to which the optical fiber array is bonded and fixed is placed on the upper surface of the jig 49, and at a predetermined position (optical fiber core enlarged portion),
The groove 23 for inserting the magnet-integrated optical element array 50 is processed. The groove is formed at a predetermined angle so that the reflection between the optical fiber and the optical element is reduced. Groove processing is performed so as to cut all the ferrule capillaries 7 and the glass substrate 52 of the optical fiber array. The bottom surface of the groove 23 is formed parallel to the reference plane R3 of the glass substrate. Figure 10 (m)
If the reference side R1 of the glass substrate or the reference side R2 having a predetermined relationship with the reference side R1 of the optical element is formed on the magnet 6 on the bottom surface of the cut groove 23, the process proceeds to step R2.
The optical elements are aligned with the corresponding optical fibers and adhesively fixed. The adhesive used here has a small refractive index adjustment and a small transmission loss so that the light on the optical path is less reflected and absorbed. As a result, the magnet-integrated optical element array 50 is fixed in an accurate position and angular relationship with respect to the reference plane R3 of the glass substrate 52. In the process of FIG. 10N, the magnet 6 and the glass substrate 4 are cut along the cutting line 55 between the ferrule capillaries 7.
0 is cut by a cutting grindstone to separate the embedded optical isolator array arranged at a predetermined pitch to obtain individual optical isolators. Thus, an embedded optical isolator having a predetermined incident polarization direction with respect to the glass reference plane is obtained. In this embodiment, an inexpensive substrate such as a glass substrate can be used instead of the holding member in the above-described manufacturing example, and therefore, it is possible to mass-produce the optical isolator inexpensively and easily by the optical element array method.

Fabrication Example 5 This example illustrates an optical isolator similar to that obtained by the embedded optical isolator array of Fabrication Example 4, but without the array. First, in the method of Manufacturing Example 1 (FIG. 4), steps (a) to (e) in the figure are performed to obtain an optical element which is an optical isolator element. The outline of the process is as follows.・ Polarizing glass 1 whose incident polarization plane is perpendicular or parallel to the reference side (depending on the design), Faraday rotator whose rotation angle is about 45 °, and about 45 ° to the reference plane Polarizing glass 2 having a polarizing plane is used (step (a) in FIG. 4). The angle of the above element is adjusted in advance so that the maximum isolation is obtained at a predetermined wavelength (step (b) in FIG. 4). -Adhesively fixing each in a predetermined configuration (step (c) in FIG. 4). -Polarizing glass was polished to the front of the Ag distribution layer (about 60 μm) on both the incident side and the emission side. -The optical element 5 is cut by dicing to 0.3 x 0.4 mm (steps (d) to (e)). Separately from this, as in the step (a) of FIG. 11, the TEC optical fiber 21 is adhered to the ferrule 7 (φ1.25 mm), and the ferrule end face is PC-polished and fiber-cut. Next, as shown in step (b) of FIG. 11, the TEC optical fiber-bonded ferrule 7 is processed into a V groove or a rectangular groove 59 on the glass plate 60 (here, a glass plate of t1.0) with the reference plane R3 as a reference. Then, it is adhered and fixed to (the seat of the cylindrical ferrule capillary is improved). Moving to step (c) of FIG. 11, an element and a groove 61 for inserting a magnet are processed at a predetermined portion (optical fiber core enlarged portion) of the TEC optical fiber adhesive ferrule with reference plate bottom surface R3 as a reference.
The groove is formed at a predetermined angle so that the reflection between the optical fiber and the element is reduced. Apart from this, step (d) of FIG.
At the bottom surface processing (reference plane R2), the cylindrical magnet 62 (φ1.25) is made to have substantially the same area as the ferrule groove processing surface.
And a rectangular groove 63 for element insertion placement.
Then, the magnet 60 is magnetized. Figure 11
In step (e), the reference plane R1 of the optical element 5 is inserted in the predetermined direction into the bottom of the groove 63 of the magnet 62. Grooved TEC optical fiber ferrule 7 with optical element 5 and magnet 6
Insert 2 and fix with adhesive. The reference plane R2 of the magnet has a fixed relationship with R3. It should be noted that the adhesive used here has a small refractive index adjustment and a small transmission loss so that the light on the optical path is less reflected and absorbed. As described above, since the positions of the respective members are accurately regulated through the reference planes R1 and R2, the embedded optical isolator having the predetermined incident polarization direction with respect to the reference plane R3 can be obtained.

[0039]

According to the present invention, when cutting groove processing,
By tilting the processing grindstone so that the side surface on the incident light side is tilted more largely in the groove depth direction than the side surface on the outgoing light side, reflected light from the groove end surface to the incident side can be suppressed.
In addition, as shown in the manufacturing example, when the embedded optical isolator is used, only the embedded optical isolator reference member surface is placed on the reference surface of the LD module, which does not require troublesome incident polarization direction alignment. Further, in the method of manufacturing an optical fiber embedded optical isolator using polarizing glass, it is possible to realize a low price by efficiently processing very expensive polarizing glass. A distribution layer of metal fine particles (Ag distribution layer) having a function of polarizing light on the surface of polarizing glass
A thin optical element that can be embedded between optical fibers is manufactured by leaving a region (about 50 μm) in which is present and scraping off other portions. However, since the metal fine particle layer exists on both the front and back sides, in order to use both layers efficiently, by processing the middle part in the thickness direction of the polarizing glass plate with a slicer, a wire saw, a band saw, etc., By reducing the number of troublesome polishing steps and increasing the number of elements taken from one piece of polarizing glass, it becomes possible to manufacture an inexpensive embedded optical isolator.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a conventional optical isolator.

FIG. 2A and FIG. 2B are views showing processing of an optical isolator element insertion groove of a conventional ferrule capillary.

3A and 3B are views showing processing of an optical isolator element insertion groove of a ferrule capillary.

4A to 4J are diagrams showing a sequential process of the processing method of the first fabrication example and a structure of an optical isolator.

5A to 5K are diagrams showing a sequential process of the processing method of the second fabrication example and the structure of the optical isolator.

6A to 6I are diagrams showing a sequential process of the beginning part of the processing method of the third fabrication example and the structure of the optical isolator.

7 (j) to 7 (n) are views showing a sequential process of the remaining part of the processing method of the third fabrication example and the structure of the optical isolator.

FIG. 8 is a sectional view of a laser device incorporating an optical isolator.

9A to 9I are diagrams showing the sequential steps of the first half of the processing method of the fourth fabrication example and the structure of the optical isolator.

10 (j) to (o) are diagrams showing the sequential steps of the latter half portion of the processing method of the fourth fabrication example and the structure of the optical isolator.

11A to 11E are diagrams showing a sequential process of the latter half of the processing method of the fifth fabrication example and the structure of the optical isolator.

[Explanation of symbols]

1, 2 polarized glass 3 Faraday rotator 5 Optical element 6 permanent magnet 7 Ferrule Capillary 21 optical fiber 23 groove 30 LED light source 31 Collimator 32 optical sensor 33 Optical power meter 34 Magnet 37 groove 38 Embedded optical isolator 39 grooves 40 Standard Base Material 45 Strip array optical element 47 cutting line 48 fixed groove 49 Temporary fixing jig 50 Magnet integrated optical element array 52 glass substrate 54 groove 55 cutting line

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[Procedure amendment]

[Submission date] January 28, 2003 (2003.1.2
8)

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Change

[Correction content]

[0017]

EXAMPLE A constitution of the present invention capable of reducing light reflection is illustrated in FIG. Here, the same reference numerals as those in FIG. 2 are used. In this case, as shown in (a), the groove is processed at a certain angle to escape the reflected light with respect to the optical axis direction to form the rectangular groove 23, but as shown in the side surface of (b). By inclining the processing grindstone by an angle θα, the angle on the incident side with respect to the perpendicular of the rectangular groove 23 is made larger than the angle on the emitting side. With a diamond blade used for grooving
Deflection occurs, and the actual groove side angle is θα-θ1 and
θα + θ2. Therefore, the diamond blade
If the groove processing angle by θα-θ2 is
The angle on one side is (θα-θ
2) + θ2 = θα, and the value as designed can be obtained.
On the other hand, the side surface on the opposite side is (θα-θ2) -θ1 = θα-θ
1-θ2, and the groove machining angle becomes smaller than the design value θα.
It However, there is a problem that the end face reflected light which is prevented by providing a predetermined inclination with respect to the optical axis increases the returned light as the end face inclination becomes smaller, but the angle on the incident side (LD side) of the embedded optical isolator is By adopting the configuration of the present invention in which the groove is processed to be large, the return loss and the
It becomes an embedded optical isolator with good junction loss (because reflection on the output side is blocked by the optical isolator).

[Procedure amendment]

[Submission date] June 4, 2003 (2003.6.4)

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Correction content]

[Claims]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Change

[Correction content]

[0017]

EXAMPLE A constitution of the present invention capable of reducing light reflection is illustrated in FIG. Here, the same reference numerals as those in FIG. 2 are used. In this case, as shown in (a), the groove is processed at a certain angle to escape the reflected light with respect to the optical axis direction to form the rectangular groove 23, but as shown in the side surface of (b). By inclining the processing grindstone by an angle θα, the angle on the incident side with respect to the perpendicular of the rectangular groove 23 is made larger than the angle on the emitting side . However, and angle of but edge reflection light be prevented by providing a predetermined inclination with respect to the optical axis has a problem that the return light is increased as the end face inclination becomes small, the incident side of the embedded type optical isolator (LD side) By adopting the configuration of the present invention in which the groove is processed so as to be large, it becomes a buried optical isolator with good return loss and junction loss (because reflection on the output side is blocked by the optical isolator). ).

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2H037 AA01 BA02 BA31 DA02 DA12                       DA15 DA17                 2H049 BA02 BA08 BB03 BB06 BB61                       BC25                 2H099 AA01 BA02 CA05 CA11 DA01                       DA05

Claims (3)

[Claims] 1. An optical component having an optical element, an optical fiber, and an embedding groove that embeds the optical element across the optical fiber, wherein an incident light is included in a cross section of the embedding groove parallel to the optical fiber. An optical component characterized in that the side surface on the light side is more inclined than the side surface on the emission side with respect to the groove depth direction. 2. The optical component according to claim 1, wherein the embedded groove is formed by a mechanical working method, or a mechanical working method and a chemical polishing working method. 3. The optical component according to claim 1, wherein the optical element is an optical isolator element including a polarizer and a Faraday rotator.