JP3420231B2 - Embedded optical isolator using polarizing glass - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to optical communication, optical measurement, etc.
Optical isolators used inToRelated. [0002] 2. Description of the Related Art Used as a light source for various optical systems.
The semiconductor laser reflects back from the optics coupled to it.
It is known that the light makes the oscillation unstable.
Isolators are used to prevent this. recent years
With the rapid expansion of optical communication systems in
On the other hand, demands for downsizing and price reduction are increasing. FIG. 1 shows the configuration of a conventional basic isolator.
Shown in Polarizers 10a on both sides of the Faraday rotator 11,
10b is a magnet for magnetizing the Faraday rotator around it.
In this configuration, the stones 12 are arranged, and the optical fibers 8a and 8b
Require two condenser lenses 9a and 9b.
With this configuration, light is incident in the forward direction (the direction of the arrow C in the figure).
Light is transmitted and enters in the opposite direction (the direction of the arrow D in the figure)
Light is blocked, realizing the function as an isolator
But requires many optical elements, and
The structure of is large. On the other hand, such a complicated method is not enough.
A simple and simple method is disclosed in JP-A-3-63606 and
No. 4-307512. [0005] This method is called an "embedded type" and uses a substrate.
And fix the embedded optical fiber to the die.
Groove that crosses the optical fiber with a saw
The device is manufactured by embedding and fixing the device.
It is. According to this, optical axis alignment is used for the production of optical isolators.
Is not required, and the fabrication is greatly facilitated. Only
On the other hand, the light output from the optical fiber passes through the element part
When diffraction occurs, the thickness of the element becomes a neck and inserts
Problems such as an increase in loss occur. In contrast
To expand the core of the optical fiber by local heating
Methods such as reduction are taken. [0006] SUMMARY OF THE INVENTION An embedding using a polarizing glass
Since embedded optical isolators are polarization-dependent,
When used as a module, the polarization
The direction had to be adjusted. The settings for making this adjustment
If the equipment and man-hours are required,
It becomes a top. Also, with ink, laser marker, etc.
There is also a method of displaying the position of the incident surface, but since the components are small,
Both marking accuracy and positioning accuracy are low
In addition, it has been difficult to accurately adjust the plane of polarization of the incident light. In the case of a general optical isolator, the input
Eliminating the return light reflected at the interface between the emitted light and the optical element
In order to offset the shift of the incident and exit position of light
A method of tilting the element surface obliquely with respect to the axis is used.
The recessed optical isolator has a rectangular groove processing part that becomes the element insertion part
There is a problem that the optical connection loss is deteriorated by making the angle oblique.
This is because the element arrangement groove is slanted to reduce reflected return light.
However, if the oblique angle is increased, the connection loss
Also increases. Therefore, the required return loss in the design
Grooving and connection loss
There is a need. However, a groove using a diamond blade
When insert cutting is performed, the work (ferrule)
When the blade hits and when it comes out of the workpiece, it
Les easily occur. As a result, the groove shape of the work
A problem arises that the shape (upper area) becomes large (the processing surface is a whetstone
Wider due to blurring, narrower in depth direction (grinding stone
About the same as the width)). In addition, a rectangle serving as a light entrance / exit surface
On the cut surface cut with a diamond blade,
Due to the large surface roughness, the adhesive can be used when embedding and bonding optical elements.
Minute air bubbles easily enter between cut surfaces, causing loss and reflection
In some cases, there is a case where the side surface of the rectangular groove is mirror-finished.
You. As a mirror finishing method for this cut side surface,
There is a method called a chair. For cutting wheels and workpieces
Use a polishing liquid (cerium oxide, colloidal silica, etc.)
Cutting and polishing at the same time. However
Process, the upper part of the groove, which requires a lot of polishing liquid, becomes wider.
Machining side surface cutting more than the diamond blade cutting described above.
Les increases. The groove formed in this state has the specified setting shape
Return loss and connection loss
is there. This is shown in FIGS. 2A and 2B below.
Explaining in the processing method 1, a fiber supporting the optical fiber 21 will be described.
The interface angle of the optical element embedding groove 23 of the ferrule 20 is set at the upper surface.
As shown in the figure, even if groove processing is performed at a predetermined
Trapezoidal angle caused by machining blur as seen from the groove state
Degrees θ1 and θ2 (usually θ1 = θ2) are added, and the design inclination
The connection loss increases because the angle is larger than the angle.
You. [0010] Means for Solving the Problems To solve the above problems,
The present invention (1) Polarizing glass optical element used for embedded optical isolator
The plane of incidence of the element is at a predetermined angle with respect to the reference side of the element shape.
And a ferrule that constitutes an embedded optical isolator
Tool, magnet, reference plane member (such as LD)
Transfer the reference side angle of the glass optical element to the reference surface
In order to obtain, using a rectangular magnet,
Perform parallel rectangular groove processing, and configure the optical element in this groove.
You. As a result, the magnet reference side is placed on the holder surface of the reference member.
Embedding light in a predetermined incident polarization direction by positioning
An isolator is obtained. More specifically, the present invention
Optics composed of optical glass and Faraday rotator
Element holding the optical fiber and embedding said optical element
Of a ferrule capillary having an embedded groove for receiving
In the embedding groove, fixed in alignment with the optical fiber,
Applying a magnetic field to the Faraday rotator around an optical element
Embedded optical isolator with permanent magnets
The optical element is formed in a rectangular parallelepiped shape (including a cube),
Insertion of the reference side of the optical element into a permanent magnet
And a reference side substantially parallel to the bottom of the rectangular groove.
Forming a reference side of the optical element with a rectangular groove of the permanent magnet;
Into the ferrule capillary
Inserted and fixed in the embedding groove to determine the insertion position of the permanent magnet
A rectangular holding groove and a bottom substantially parallel to the holding groove.
The holding groove of the holder member having a reference holder surface
The permanent magnet having a reference side inserted and fixed to the optical element.
By inserting and fixing the reference side of
Provide a dependent embedded optical isolator. (2) The present invention also relates to
Ferrule with groove for optical element insertion in fixed position
Le capillary and the groove bottom of its ferrule capillary
Positioning and fixing are performed on the side and the element reference side. More specific
Thus, the present invention provides a polarizing glass and a Faraday rotator.
The optical element holding the optical fiber and
Ferrule having embedded groove for embedding optical element
Align with the optical fiber in the embedded groove of the capillary
Fixed in a state and the Faraday time around the optical element.
Embedded optical isolator with permanent magnets that apply a magnetic field to the trochanter
A ferrule to which the optical fiber is adhesively fixed.
The capillary is fixed to a predetermined position of the substrate in advance,
A rectangle into which the optical element is inserted with reference to the substrate surface
Insert the groove into the ferrule capillary at a predetermined position and angle.
The optical element is formed in a rectangular parallelepiped shape,
Align the reference side of the element with the bottom of the groove of the ferrule capillary.
By locating and positioning by hitting the surface
It is characterized by a predetermined incident polarization direction with respect to the plate bottom
To provide a polarization dependent embedded optical isolator. this
In the case, the optical element formed in a rectangular parallelepiped is a rectangular magnet.
Use the one that is fixed in the groove, and
Insert into the rectangular groove of the pillar, and extend to the reference side of the optical element.
Or a reference surface of the magnet set in a predetermined relationship therewith,
The ferrule capillary is inserted into the groove bottom
To position the board,
The incident polarization direction may be fixed. In this form
According to this, in addition to the precise alignment of the incident polarization direction,
Easy to assemble optical isolators, glass plate, etc. as reference base
It is possible to use cheap materials of
You. (3) On the other hand, the above-mentioned groove shape becomes trapezoidal (upper wide).
Since the groove formed in this state is different from the specified set shape,
Regarding the problem that the return loss and connection loss deteriorate,
Akira said in the above embedded optical isolator,
The side on the light incident side of the permanent magnet embedding groove to be applied to the capillary
Embedded type characterized by being inclined with respect to the groove depth direction
The problem is solved by an optical isolator. [0012]In one aspect of the invention,Polarization dependent embedded light
Manufacturing isolatorsHit, Metal fine particle distribution layer
Polarization plane incident on the surface and at a predetermined angle to the reference side
And the rotation angle is about 45 °.
° Faraday rotator and metal particle layer
On the surface and about the first polarizing glass.
And a second polarizing glass whose polarization plane is oriented at 45 °,
Make sure that the layer of fine metal particles faces the Faraday rotator.
To form a laminate, and the first and second polarizing
Lath up to the front of the metal fine particle layer on both the entrance and exit sides
Polished, and the polished laminate is
Dicing into a rectangular parallelepiped, thus obtained
A permanent magnet made by magnetizing a rectangular parallelepiped thin element in a predetermined direction
Embed in grooveIncluding processEmbedded Faraday rotator
Manufacturing methodUse.otherIn the form of,Metal particle distribution layer
On both surfaces and incident at a predetermined angle with respect to the reference side.
The first polarizing glass whose light surface is facing and the rotation angle is about
45 ° Faraday rotator and metal fine particle distribution
A row layer on both surfaces and with respect to the first polarizing glass
Second polarizing glass whose polarization plane is oriented at approximately 45 °
Are laminated and bonded alternately many times, and the laminate is
And cut the obtained optical element array into a permanent magnetic
Inserting and bonding into the groove of the stone, the first and second polarizing glass
The intermediate portion between each of the two metal fine particle arrangement layers is
Excise withIncluding processOptical element embedded in permanent magnet
The manufacturing method of the optical isolator elementUseI do. [0013]ChangeIn other forms,Metal layer with both layers
Polarization plane incident on the surface and at a predetermined angle to the reference side
And the rotation angle is about 45 °.
° Faraday rotator and metal particle layer
Having on both surfaces thereof, and being substantially opposite to the first polarizing glass.
With a second polarizing glass whose polarization plane is oriented at about 45 °
Are laminated and bonded alternately many times to form a laminate,
The optical element obtained by cutting the layer body at predetermined intervals in the stacking direction
The array is formed by a permanent magnet having a plurality of grooves formed at regular intervals.
Into each of the first and second polarizing glasses.
Cut off the middle part between both wiring layers together with the permanent magnet,
From the first and second polarizing glasses and the Faraday rotator
A rod-shaped magnet having a plurality of optical elements
Insert and fix into grooves formed in multiple embedded ferrules
And then cut the bar magnet between the ferrulesProcess
includingOf the optical isolator element embedded in the ferrule
Manufacturing methodUseI do. [0014] DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical isolator using an optical isolator.
D (laser device) manufacturers can easily assemble
The LD module stem surface and package surface
Just put an optical isolator with a reference base member on
Embedded optical elements that do not require incident polarization alignment
It is intended to provide a type optical isolator. In the present invention
Is straight to facilitate alignment of the incident polarization plane with the base member surface.
Rectangular magnet, rectangular optical element, for matching sides
Of each rectangular groove of the
Make sure you get right. Note that the embedded optical isolator
By covering the grooved part with a member, structural reinforcement and reliability improvement
The effect is also obtained. In the present invention, two polarizing glasses and a Faraday
An optical element using a rotator is used. In this case, the polarization
Glass has metal fine particle distribution parts (about 50 μm) on both sides.
In the preferred embodiment of the present invention,
Cut in the middle or leave only one side
The thin optical element is cut by polishing and polishing.
Make a child. Optical fiber with low loss by using thin elements
An embedded optical isolator can be realized. Ie thick element
The transmission loss increases due to the diffraction and scattering of light.
However, by making the element thinner, light diffraction and scattering can be reduced.
Reduction losses can be reduced. [0016] Wrap, polish to cut one side of expensive polarizing glass
Non-functional polarizing glass due to the large number of process steps
Use a relatively fine-grained whetstone to cut off the part
And cut two pieces from one piece of polarizing glass.
In addition, the lapping and polishing steps can be omitted. However
In order to achieve this, the method of making the cut surface roughness close to the mirror surface
1) After cutting using a relatively coarse-grained blade,
Use a method of passing a blade with a diamond size or a T-type grinding wheel (side
Whetstones that can be surface processed, such as cup whetstones)
2) Oxidized cerium, roller
Perform cutting processing while applying idal silica etc. to the workpiece
There is a way. The invention of the above (1) of the present invention provides a buried optical
In the isolator, the optical element used is polarizing glass
And a Faraday rotator.
The support holding the iva is a ferrule capillary.
And a rectangular parallelepiped permanent magnet that applies a magnetic field to the Faraday rotator
Shape (including cubic) elements can be inserted and positioned.
The bottom of this groove is almost the same as the reference side of the magnet.
Parallel and optical fiber inserted into ferrule capillary
The optical element is fixed in place and the optical element is
For a holder member with a rectangular groove formed by groove processing for embedding stone
Of the magnet inserted and bonded to the rectangular groove
Place the reference side. The bottom of the rectangular groove of the holder member is a magnet
This is the groove bottom that is positioned with respect to the reference side.
The surface of the holder member formed in parallel to the
The reference holding surface is positioned and held by the holding surface on the side.
Polarization dependent embedded optical isolator
It is a thing that I did. In this way, the embedded optical isolator
Polarizing glass optical element used for the translator
At a predetermined angle to the reference side of the shape,
Ferrules, magnets, and reference planes that make up the optical isolator
Reference side angle of optical element using polarizing glass with respect to material
To transfer the current to the reference surface
Substantially parallel rectangular groove processing is performed on the quasi side, and this groove
Construct an optical element. This allows the reference member surface to be
A buried optical isolator with the specified incident polarization direction can be obtained.
You. On the other hand, when the configuration (2) is adopted, the light coupling
Combined loss can be reduced, but the principle
2 is shown in FIG. Here, the same reference numerals as those in FIG.
Use In this case, the groove processing is shown on the upper surface of (a).
At an angle to allow the reflected light to escape with respect to the optical axis direction.
Groove processing is performed to form a rectangular groove 23, which is shown on the side of FIG.
As described above, by tilting the processing grindstone, the rectangular groove 23 is formed.
Angle θ2 on the incident side with respect to the perpendicular to
Larger, the coupling loss degradation is almost as designed.
You. To explain this in more detail,
Since the groove inclination angles θ1 and θ2 are almost the same,
Angle is the same angle between the incident side and the outgoing side
And θα + θα = 2θα, and according to the configuration of the invention,
Combined light on the entrance and exit sides of the processed embedded interface
The axis shift amount is substantially the same as the design value, θα + θ1 + θα−θ2.
= 2θα, so that there is little deterioration in junction loss. However, it is necessary to provide a predetermined inclination with respect to the optical axis.
The reflected light at the end face can be prevented by reducing the inclination of the end face.
Although there is a problem that return light increases, the embedded optical isolator
Groove processing to increase the angle on the light incident side (LD side)
By performing the configuration of the present invention, the return loss and the connection
A good embedded optical isolator with high combined loss (emission side
Reflection is blocked by the optical isolator). [0020] 【Example】Example 1 A first embodiment of the present invention will be described with reference to FIG. Polarization
Conventional polarization-dependent optical isolators using glass
When used for D module,
It was necessary to adjust the polarization direction. This new recessed light
The isolator is difficult to align when assembling the module
It is a structure that does not need to be
Highly accurate polarization direction alignment, mass production, and low cost
Is possible. Figure 4 shows the standard construction method.
In this case, as shown in FIG.
Polarized glass with incident polarization plane facing the row (by design)
1 and Faraday rotation with a rotation angle of about 45 °
Trochanter 3, polarization plane oriented at approximately 45 ° to reference plane
Is used. These have many optical elements
It is a bare plate large enough to be taken individually. As shown in FIG. 4B, these raw plates 1, 2,
3 has a magnet 34 for magnetically saturating the Faraday rotator
On a peak wavelength measuring instrument to determine the mutual angular relationship
You. That is, the light from the LED light source 30 is
1 to the base plates 2, 3, 1 in the reverse direction,
2 and then the optical power meter 33
Measure Fix the polarizing glass 1 and the Faraday rotator 3
Rotating the polarizing glass 2 in the fixed state
Determine the angle at which the solution is obtained. In this way, the blank
Maximum isolation in advance at a fixed wavelength
It is assumed that the angle is adjusted so as to obtain. Then,
Each of the base plates was obtained with the specified configuration using optical adhesive.
Adhere and fix. As shown in FIG.
Before the metal fine particle (Ag) layer on both the incident side and the exit side
(To about 60 μm). Thus a thin device
(For example, 0.3mm to 0.5mm in thickness)
Become. Next, as shown in FIG.
Dicing using a grindstone and the size of many optical elements
(For example, 0.3 mm × 0.4 mm). FIG.
(E) shows the obtained optical element 5, and R1 is its reference side.
And a certain angular relationship with respect to the polarizing glasses 1 and 2.
You. As shown in FIG. 4F, the optical element 5 is attached to the permanent magnet 6.
Perform rectangular groove processing for insertion positioning. Magnet
The dimensions are, for example, 2.0 mm × 1.0 mm × (thickness 0.3 to
0.5) mm. The length of the groove 23 is the thickness of the optical element 5
equal to t. The bottom of the groove 23 and the reference side R2 are formed substantially in parallel.
By doing so, the two have a fixed relationship. After grooving,
A predetermined magnetization is performed on the magnet. Next, as shown in FIG.
23, the reference side R1 of the optical element 5 is inserted in a predetermined direction and
I fix it. As a result, the polarization angle of the polarizing glass
The reference side R1 of the optical element 5 at a predetermined angle is the reference side R of the magnet.
2 is defined as a fixed angle relationship. 4 (h)
As shown, the TEC optical fiber 21 is connected to a ferrule capillary.
-7, PC polishing of ferrule end face, and
Fiber cut. TEC optical fiber bonded fiber
The element is placed in the specified part of the ferrule (enlarged part of the optical fiber core).
And a groove for magnet insertion is formed to form a rectangular groove 37.
You. Groove processing to reduce reflection of optical fiber and element
At a predetermined angle. Grooved TEC optical fiber ferrule
Rectangular magnet 6 with optical element inserted into groove 37 of capillary 7
The reference side R2 is inserted and fixed. Adhesive used
Is the index of refraction so that light on the optical path is less reflected and absorbed.
Use one with less adjustment and transmission loss. like this
Thus, the embedded optical isolator is completed. 4 (i)
To fix the embedded optical isolator in place
The reference base member 40 for the use is used. This base member
A groove 39 is provided for abutting the rectangular magnet.
Is parallel to the reference surface R3 which is the bottom surface of the base member 40.
It is. Then, as shown in FIG.
Inserted embedded optical isolator 38 into base member 40
Perform adhesive fixation. In this way, the embedded optical isolator
Is a predetermined incident deviation with respect to the reference surface R3 (base member bottom surface).
It will have a light direction. [0025]Example 2 Referring to FIG. 5, a buried optical device according to a second embodiment of the present invention will be described.
A method for manufacturing an isolator will be described. This example is for high-volume production
Show the law. First, perpendicular or parallel to the reference side (depending on the design)
Polarization glass 1 whose incident polarization plane is oriented
Faraday rotator with an angle of about 45 °, reference
Polarization plane whose polarization plane is oriented at approximately 45 ° to the plane
Lath 2 is used. The above elements are the same as in FIGS.
As shown in FIG.
In advance, it will be the maximum isolation
The angle is adjusted as shown in FIG.
Each element is cut along the cutting lines 41, 42, 43
Strip-shaped cut piece (cut element width: 0.3 mm, initial in longitudinal direction
(10 mm depending on the element size). Next, as shown in FIGS.
Optical glass 0 °-Faraday rotator-Polarized glass 45 °-
Repeat the Faraday rotator in order and repeat
Set. At this time, make sure that the relative adhesion angle of each element does not shift.
Then, align each element side by side while abutting against the reference surface of the jig.
To wear. Next, as shown in FIG.
Strip the board in a direction perpendicular to the element array direction (element width
0.4 mm). The obtained strip array optical element 45 is
It is shown in FIG. As shown in FIG.
The magnet 6 is grooved with a width of 0.45 and a depth of 0.35 mm.
You. Next, as shown in FIG.
(A) The optical element 45 is inserted and fixed by bonding. FIG. 5 (h)
Cut the center of the polarizing glass plate of the optical element with magnet
Separated into each optical element by cutting line 46 as margin
You. However, the Ag metal fine particle distributing portion is not shaved. (Cut
The cutting process is performed so that the filter is about 0.35 mm). Thereafter, FIGS. 4H, 4I and 4J show the results.
The corresponding steps are shown in FIGS. 5 (i), (j) and (k).
Therefore, it will be implemented and completed. The process is summarized below.
It is. ・ In the direction that the magnetic application condition is appropriate for the element configuration,
Magnetized, glued TEC optical fiber to ferrule,
PC polished ferrule end face and fiber cut
I do. ・ Specification of TEC optical fiber bonded ferrule capillary
Insert the magnet with the element bonded in the area (enlarged part of the optical fiber core)
Groove processing required (Reflection of optical fiber and element
At a predetermined angle to reduce the number). ・ Groove TEC optical fiber ferrule capillary
Insert the magnet-integrated optical element into the
Glue that reflects and absorbs less light on the optical path
Use a material with low refractive index adjustment and low transmission loss
). .Base for fixing the embedded optical isolator in place
Use a quasi-base member (a rectangular magnet
There is a groove to abut, this groove is on the bottom of the base member
Is parallel to). ・ Adhesive fixation to embedded optical isolator and base member
Do. ・ Predetermined incident polarization method with respect to the reference plane (base member bottom)
It becomes a buried optical isolator. [0028]Example 3 6 and 7 show a buried optical isolator according to another embodiment of the present invention.
Shows the manufacturing process of an optical isolator using the
You. In this example, first, the steps of FIGS.
It is. These steps are similar to those shown in FIGS.
You. However, in this embodiment, the optical element array is
Used as an array without being separated into elements. here
The steps up to this point are summarized as follows. ・ Injection perpendicular or parallel to the reference side (by design)
Polarizing glass 1 whose polarization plane is facing, and rotation angle of about 4
5 ° Faraday rotator 3, relative to reference plane
Using polarizing glass 2 whose polarization plane is oriented at approximately 45 °
(Step (a)). ・ The above-mentioned element has the maximum
Adjust the angle to achieve isolation (process
(B)). ・ Each strip is cut (cut element width: 0.3m
m, 10 mm depending on the initial element size in the longitudinal direction
(Step (c)). -Polarizing glass 0 °-Faraday rotator-Polarizing glass 45
°-Faraday rotator
I fix it. At this time, the relative bonding angle of each element does not shift
As shown in the figure, the elements are lined up and
(Steps (c) to (d)). ・ Direction perpendicular to the optical element array adhesive plate in the element array direction
Cut into strips (element width 0.4 mm) and cut into optical element array 4
5 (steps (d) to (e)). On the other hand, as shown in FIG.
Groove processing of 0.45 width and 0.35 mm depth in rectangular magnet 6
Are processed a number of times at a predetermined pitch (2 mm). FIG. 6 (g)
The reference of the strip array optical element 45 is
A large number of pieces are bonded and fixed in accordance with the surface R1. Magnet groove 2
3 has a magnet reference surface R2 (in this example, an optical element inserted).
Side). As shown in FIG. 6 (h), magnets are already bonded
Cut off the center of the polarizing glass plate of the optical element (however,
Do not remove the Ag wiring section. For example, the margin is 0.35m
m) By performing the cutting process along the cutting line 47
Separation into the form of an individual optical element array 50 integrated with a magnet.
The obtained magnet-integrated optical element array 50 is shown in FIG.
You. The magnets 6 of this array are provided with magnets appropriate for the element configuration.
Magnetization is performed in a direction that makes the condition that the seal can be applied. Moving to the step of FIG.
Glue the bar 21 to each ferrule capillary 7,
Polish the ferrule end face and cut the fiber.
You. Temporarily fix the obtained ferrule capillary 7 to the jig 4
9 in the ferrule fixing groove 48, and
The ferrule capillary 7 to which the bar 21 has been attached
Inserted magnet with element bonded at the location (enlarged part of optical fiber core)
Process rectangular groove 23 (groove processing is performed with optical fiber
A predetermined angle is set so that the reflection of the element is reduced).
The groove processing at this time is performed by the TEC optical fiber bonding ferrule cap.
Simultaneous arrangement of multiple pillars at a specified pitch and location
To do. In the step of FIG. 7 (k), the grooved T
EC optical fiber ferrule array with magnet integrated optical element
The ray 50 (FIG. 6 (i)) is inserted and adhered and fixed. for
Adhesives that reflect and reduce light on the optical path
Use a material with low refractive index adjustment and low transmission loss
You. In FIG. 7 (l), the embeddings arranged at a predetermined pitch
The magnet 6 of the embedded optical isolator array is cut between ferrules.
And remove it from the jig. With optical isolator
Many magnets can be obtained. Peel off from temporary fixing jig and bond
Wash and remove the agent (temporary for the above embedded optical isolator)
Temporary fixing to stop jig uses hot melt type wax
Was). Separately, as shown in FIG.
The member 40 is formed by a base similar to that described with reference to FIGS.
Prescribe embedded optical isolator using quasi-base member 40
(This base member has a rectangular magnet reference
A groove is provided for abutting the surface R2.
(It is parallel to the reference plane R3 which is the bottom surface of the base member.) Next
Insert and fix to embedded optical isolator and base member with
Do. FIG. 7 (n) shows the reference plane R3 (base member bottom face).
To provide a buried optical isolator that
Optical isolator unit with optical fiber
You. FIG. 8 shows an LD module according to each embodiment of the present invention.
Here is an example of a practical example incorporated in the system. LD module is ceramic
Substrate 51, a stem 5 having a Si-V groove on a reference surface of the substrate.
The LD chip 55 and the monitor PD 54 supported by
And attach the lead frame 57 to the back of the board 51
The transfer mold 5 made of epoxy resin
3 and fixed with transparent mold resin 56
In the embedded optical isolator of the present invention,
The reference surface R3 of the holder member is mounted on the reference surface of the substrate 51.
It is fixed in the state where it was done. For this reason, the optical element
A reference side (surface) R1, a magnet reference side (surface) R2,
The reference planes R3 of the polarizing members are parallel, and the polarizing glass 1, 2
Has a certain relationship with the LD module. [0033]Example 4 9 to 10 show an embedded type according to still another embodiment of the present invention.
Manufacturing process of optical isolator by optical fiber array method
Is shown. In this example, an inexpensive glass substrate is used as the holding substrate.
And permanently fix the ferrule capillary to it
Then, the reference surface of this glass substrate and the optical element (polarizing plate and
Reference surface (side) (with magnet attached)
In the case of a body-shaped optical element, the reference surface (side) of the magnet
Easy to assemble optical isolator by fixing
Becomes possible. In this example, first, FIGS.
Array with multiple optical elements embedded in the magnet
Produce i. This step corresponds to steps (a) to (f) in FIGS.
Since it is the same as (i), reference was made to Example 3 for details.
No. The steps so far are summarized as follows. ・ Enter perpendicular or parallel to the reference side (by design)
Polarizing glass 1 whose polarization plane is oriented, and the rotation angle is approximately
45 ° Faraday rotator 3 and reference plane
Using a polarizing glass 2 whose polarization plane is oriented at approximately 45 °
(Step (a)). ・ The above elements must be
Adjust the angle so that the isolation becomes
(B)). ・ Each is strip-shaped cut (cut element width: 0.3mm,
Depending on the initial element size in the longitudinal direction, 10 mm
(Step (c)). ・ Polarizing glass 0 °-Faraday rotator-Polarizing glass 4
5 °-Faraday rotator
Adhesion and fixation (steps (c) to (d)). At this time,
Push each element against the reference plane so that the relative adhesion angle does not shift.
Adhere side by side while matching. ・ Direction of the optical element array adhesive plate in the element array direction
Cut into strips (element width 0.4 mm) in the direction
45 (steps (d) to (e)).・ Cube magnet
A groove with a width of 0.45 and a depth of 0.35 mm is applied to
A large number of switches (3 mm) are processed (step (f)). ・ The strip array optical element 45 is used as the reference plane in the magnet groove 23.
At the same time, a large number of wires are bonded and fixed (step (g)). ・ Cut the center of the polarizing glass plate of the optical element with magnet
(However, do not cut the Ag section: this cut
The cutting process is performed as in the case of 0.35 mm).
(Step (h)). ・ In the direction where the magnetic application condition is appropriate for the element configuration
The magnet 6 is magnetized (step (i)). Apart from the magnet-integrated optical element array 50, FIG.
In the ten steps (j) to (l), a large number of optical fibers
An array having a ferrule fixed to a glass substrate is prepared.
That is, first, in step (j) of FIG.
To the glass substrate 52 (other stable inorganic materials are also possible)
A rectangular groove 54 for arranging ferrules at predetermined positions (or
V groove) processing is performed. Next, in step (k) of FIG.
Ferrule with EC optical fiber 21 embedded and bonded
The end face of the capillary 7 is polished with PC and the fiber is cut.
You. These ferrules are arranged at predetermined positions in the groove 54,
An optical fiber array is made by fixing with an adhesive.
Next, as shown in FIG.
Reference surface of glass substrate 52 with fiber array bonded and fixed
Place R3 on a predetermined location (enlarged part of optical fiber core)
Groove 23 for inserting magnet-integrated optical element array 50
Process. Groove processing reduces reflection of optical fiber and optical element
At a predetermined angle so that Groove processing is optical fiber
All ferrule capillaries 7 and gala in the array
This is performed so as to cut the substrate 52. The bottom of the groove 23 is loose
This is performed in parallel to the reference plane R3 of the substrate. FIG. 10 (m)
In the process, the base of the glass substrate is
The reference side R1 or the magnet 6 is positioned relative to the reference side R1 of the optical element.
When a reference side R2 having a fixed relation is formed, R2
And insert each optical element to the corresponding light
Align and adhere to the fiber. Adhesion used here
The agent has a refractive index so that light on the optical path is less reflected and absorbed.
Use one with less adjustment and transmission loss. This
The magnet-integrated optical element array 50 is a reference for the glass substrate 52.
Surface R3ToAs a result, the position and angle relationship are fixed.
In the step of FIG. 10 (n), the ferrule capillary
7 cuts the magnet 6 and the glass substrate 40 along the cutting line 55
Embedded optical eyes cut with stone and arranged at a predetermined pitch
Separate the solar array to obtain individual optical isolators
You. Thus, the predetermined incident polarization direction with respect to the glass reference plane
Embedded optical isolator is obtained. This form is
Inexpensive glass base instead of the holding member in the above embodiment
The substrate such as a plate can be used.
Provides the advantage of mass production of optical isolators at low cost and easily
I do. [0035]Example 5 This example is based on the embedded optical isolator array of the fourth embodiment.
An optical isolator similar to that obtained, but with an array
An example of a method that does not use is shown. First, the method of Example 1 (FIG.
In 4), the steps from (a) to (e) in FIG.
Thus, an optical element which is an optical isolator element is obtained. Process
The outline is as follows. ・ Enter perpendicular or parallel to the reference side (by design)
Polarizing glass 1 whose polarization plane is oriented, and the rotation angle is approximately
45 ° Faraday rotator, relative to reference plane
Use polarizing glass 2 whose polarization plane is oriented at approximately 45 °
(Step (a) in FIG. 4). ・ The above elements must be
Adjust the angle so that the isolation becomes
Step 4 (b)). -Adhere and fix each with a predetermined configuration (step in FIG. 4)
(C)). ・ The polarizing glass is placed before the Ag layer on both the entrance and exit sides.
Polishing (about 60μm) ・ Light as a cut to 0.3 × 0.4mm by dicing
(Steps (d) to (e)). Different from this
Then, as shown in step (a) of FIG.
1 is adhered to ferrule 7 (φ1.25 mm)
The end face of the rule is subjected to PC polishing and fiber cutting. Next
Then, as shown in step (b) of FIG.
The worn ferrule 7 is attached to the glass plate 60 (here, t1.0).
V-groove or rectangular shape with reference to the reference plane R3.
Fabricate the groove 59 (since the cylindrical ferrule capillary is
Is fixed). Move to step (c) in FIG.
TEC optical fiber connection with reference to the reference plate bottom surface R3.
At the specified location of the arrival ferrule (enlarged portion of the optical fiber core)
The element and the groove 61 for magnet insertion are processed. Groove processing is light
Set a certain angle so that the reflection between the fiber and the element is reduced.
Put on. Separately, in step (d) of FIG.
The column magnet 62 (φ1.25) is almost the same as the ferrule groove processing surface.
Bottom processing (to be the reference plane R2) so that it has the same area
Then, the rectangular groove 63 for element insertion and placement was processed.
Then, the magnet 60 is magnetized. Step of FIG.
In (e), the optical element 5 is provided at the bottom of the groove 63 of the magnet 62.
Is inserted in a predetermined direction. Grooved TE
Insert optical element 5 and magnet 62 into C optical fiber ferrule 7
Insert and fix. The reference plane R2 of the magnet is constant at R3
Become a relationship. The adhesive used here has light on the optical path.
Adjustment of refractive index and transmission loss to reduce reflection and absorption
Use the one with less loss. As described above, the reference plane R
1, The position of each member is accurately regulated through R2.
For this reason, the embedded plane having a predetermined incident polarization direction with respect to the reference plane R3.
A plug-in type optical isolator is obtained. [0036] As described above, the embedded optical isolator of the present invention is
When using an embedded optical
Simple installation of incident polarization by simply mounting the isolator reference member surface
No need for alignment. According to the present invention, there is provided a polarizing glass.
Method for Fabricating Optical Fiber Embedded Optical Isolator by Using Optical Fiber
Efficiently process very expensive polarizing glass
Thereby, a low price can be realized. Polarized glass
Arrangement of metal fine particles having the function of polarizing light on the surface
The area (about 50 μm) where the layer (Ag arrangement layer) exists
By shaving off the remaining parts,
An optical element that can be embedded between the fibers is manufactured. However, metal
Since the fine particle layer exists on both the front and back sides, both layers are effective.
For efficient use, the middle part of the polarizing glass plate in the thickness direction
With a slicer, wire saw, band saw, etc.
By reducing the number of complicated polishing processes, one polarizing
By increasing the number of elements that can be removed from the glass,
It is possible to produce an isolator.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a configuration diagram of a conventional optical isolator. FIGS. 2A and 2B are views showing processing of an optical isolator element insertion groove of a conventional ferrule capillary. FIGS. 3A and 3B are views showing processing of an optical isolator element insertion groove of the ferrule capillary of the present invention. FIGS. 4A to 4J are diagrams showing sequential steps of a processing method according to the first embodiment of the present invention and a structure of an optical isolator. FIGS. 5A to 5K are diagrams illustrating a sequential process of a processing method according to a second embodiment of the present invention and a structure of an optical isolator. FIGS. 6 (a) to 6 (i) are diagrams showing a sequential process of an initial part of a processing method according to a third embodiment of the present invention and a structure of an optical isolator. FIGS. 7 (j) to 7 (n) are views showing a sequential process of the remaining portion of the processing method according to the third embodiment of the present invention and a structure of an optical isolator. FIG. 8 is a sectional view of a laser device incorporating the optical isolator of the present invention. FIGS. 9 (a) to 9 (i) are views showing a sequential process of a first half of a processing method according to a fourth embodiment of the present invention and a structure of an optical isolator. FIGS. 10 (j) to 10 (o) are diagrams showing a sequential process of the latter half part of the processing method of the fourth embodiment of the present invention and a structure of an optical isolator. FIGS. 11 (a) to 11 (e) are views showing a sequential process of the latter half of the processing method of the fifth embodiment of the present invention and the structure of an optical isolator. DESCRIPTION OF SYMBOLS 1, 2 Polarizing 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 groove 40 reference base member 45 strip array optical element 47 cutting line 48 fixing groove 49 temporary fixing jig 50 magnet integrated optical element array 52 glass substrate 54 groove 55 cutting line

──────────────────────────────────────────────────続 き Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G02B 27/28 G02B 6/00

Claims (1)

(57) [Claim 1] An optical element constituted by a polarizing glass and a Faraday rotator is connected to a ferrule capillary having an embedding groove for holding an optical fiber and embedding the optical element. In a buried groove, in a buried optical isolator, which is fixed in alignment with the optical fiber and in which a permanent magnet for applying a magnetic field to the Faraday rotator is arranged around the optical element, the optical element is formed in a rectangular parallelepiped shape. Then, a rectangular groove that allows the reference side of the optical element to be inserted into the permanent magnet and a reference side substantially parallel to the bottom of the rectangular groove are formed, and the reference side of the optical element is defined as the permanent magnet. The one fixed in the rectangular groove is inserted and fixed in the embedded groove of the ferrule capillary so that the optical element is aligned with the optical fiber, and the insertion position of the permanent magnet can be determined. The reference side of the permanent magnet, into which the reference side of the optical element is fixed, is inserted into the rectangular holding groove of the holder member having a rectangular holding groove serving as a function and a reference holder surface substantially parallel to the bottom of the rectangular holding groove. A polarization-dependent embedded optical isolator characterized by being fixed.