JPH0763960A - Casing structure for sealing optical element and its packaging method - Google Patents

Abstract

PURPOSE:To widen the free space around an optical element and to facilitate the operation to adjust the axes of optical fibers and to adhere these fibers by fixing the optical element, etc., to the back surface of the cover of the casing structure, then mounting this cover on a casing body. CONSTITUTION:This casing structure has a box-shaped casing body 22 opened at the upper surface and the cover 23 closing the opened upper surface. The casing body 22 has through-holes 39 for passing through the optical fiber ends connected to the optical element 32 and has a pair of side-face wall parts 27a, 27b which face each other and mount sleeves 38a, 38b for hermetically sealing these through-holes 39. On the back surface of the cover 23 facing the casing body 22, a stand 31 for fixing the optical element 32 and a pair of optical fiber holding members 36a, 36b which are arranged on both sides of this stand 31 and have the through-holes 39 for penetrating the optical fiber ends connected to the optical element 32, are arranged. Then, the optical element and the optical fibers are easily packaged to the casing structure with high reliability.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical element encapsulating casing structure and a mounting method thereof. More specifically, the present invention provides an optical element, in particular, an optical waveguide type optical element, and an optical fiber connected to the optical element for hermetically sealing the end portion of the optical fiber for inputting and outputting the signal light. And a method of mounting an optical element and an optical fiber on the housing structure.

[0002]

2. Description of the Related Art In general, a waveguide type optical element has a structure in which an optical fiber is connected to the entrance and exit end faces of an optical waveguide formed on the surface of the device to exchange optical signals. The optical fiber end face and the waveguide end face of the optical element each have a small core portion through which light propagates, such as about 10 μm. Therefore, in order to obtain a coupling with low loss between them, a fine position on the micron order is required. Adjustment (optical axis adjustment) is required. Further, in order to keep the coupling state between the element and the optical fiber stable, it is necessary to adjust the optical axes of the both and then bond and fix them. The diameter of the bare optical fiber that abuts on the end face of the element is as small as 125 μm, and it is necessary to increase the adhesive area and reinforce the adhesive strength by passing a capillary (fine cylindrical component) or the like through the adhesive portion.

Therefore, the housing for encapsulating the optical element having the above-mentioned structure must be capable of encapsulating both the optical element and the optical fiber as a matter of course. In addition, as a general process sequence, after the optical element chip is firmly fixed in the housing and the optical element requires electrical wiring, first, the electrode lead and the element electrode previously sealed in the housing are attached. Then, the optical fiber penetrating the housing is connected to the end surface of the optical element with its optical axis adjusted.

After the above steps, the case is hermetically sealed by soldering the gap between the bare optical fiber whose surface has been metallized in advance and the fiber drawing bush of the case, and then the case. This is done by sealing the body and lid by soldering or welding.

The general structure of such a casing is
For example, as shown in FIG. 1 (1), it is a box-shaped housing with a lid having an element and an optical fiber accommodating portion. In this case, the electrodes can be pulled out easily by passing a commercially available solder-sealed connector through the side wall of the housing. For example, the inner diameter of 1mm
A pipe-shaped component (bush) of a certain degree is penetrated through the side wall of the housing in advance and hermetically joined by welding or soldering, and the optical fiber drawn into the housing through the bush is soldered to the bush. By doing.

The conventional case structure as described above has a merit that the shape of parts is simple and the number of parts is small, so that the number of sealing points required in the subsequent process is small.
However, in the above box-shaped casing, the space where the optical element and the optical fiber housed inside the casing can be handled from the outside is only from one open surface corresponding to the lid portion. Therefore, it is very difficult to adjust the optical axis of the optical fiber and bond and fix it to the end surface of the optical element held in the housing. This is because when adjusting the optical axis, the optical fiber needs to be gripped by the chuck of the external fine movement table in order to give fine movement, rotation, and tilt movement to the optical fiber in the front-back, up-down, left-right directions. In addition, the range in which the fiber held by the chuck can be moved is limited, and the degree of freedom in adjusting the optical axis is reduced. It is a general request to make the housing size as small as possible, but in the conventional housing structure as described above, this makes the optical axis adjustment work even more difficult.

When the fiber gripping portion at the time of adjusting the optical axis is not the inside of the housing but the outside of the housing, that is, the protective coating portion of the fiber extending outward from the housing, the degree of freedom in adjusting the optical axis increases, Since the protective coating to be gripped is generally made of a soft material such as nylon or polyester, the accuracy of gripping is inferior to the case of directly gripping the glass portion, and the accuracy of optical axis adjustment is also low. In the fiber bonding step, after adjusting the optical axis and determining the position, the element and the fiber are once separated and the adhesive is applied, and the optimal optical axis position determined previously is again measured.
It is necessary to reproducibly move the fiber, and not only the precision of the fine movement jig but also the precision of the fiber gripping portion are required.

[0008]

SUMMARY OF THE INVENTION According to the present invention, it is difficult to adjust the optical axis of an optical fiber and perform a bonding operation on the end face of an optical element fixed to the conventional box-shaped casing structure as described above. In order to solve the problem, when fixing the optical element in the casing structure, it is not necessary to perform it in the box-shaped casing as in the conventional case, but it can be performed on the flat lid surface and is fixed. An object of the present invention is to provide an upper housing structure for encapsulating an optical element and a mounting method for the optical element, in which the free space around the optical element can be remarkably widened and the alignment and bonding of the optical fiber to the optical element can be performed very easily. .

[0009]

SUMMARY OF THE INVENTION In order to solve the above problems of the prior art, the present invention fixes an optical element or the like to the lower surface of a lid of a casing structure, and then attaches this lid to the casing main body. It is characterized by being attached to.

That is, a casing structure for encapsulating an optical element of the present invention is a container for accommodating and encapsulating an optical element and an end portion of an optical fiber connected to the optical element, which is a box-shaped casing having an open upper surface. A body body and a lid body that closes the open upper surface, and the housing body has a through hole for penetrating an end of the optical fiber connected to the optical element, and the through hole is formed. A pedestal for fixing an optical element on a lower surface of the lid body facing the housing body, the pedestal having a pair of mutually opposing side wall surface portions on which sleeves for hermetically sealing are mounted, A pair of optical fiber holding members, which are arranged on both sides of the pedestal and have a through hole for penetrating an optical fiber end connected to the optical element, are arranged. .

Further, in the casing structure of the present invention, the optical element is an optical waveguide type optical element, and the optical element is electrically connected to the lid and the optical element mount arranged on the lower surface thereof. A means for attaching an electrode for controlling by a signal may be provided.

According to the method of mounting an optical element and an optical fiber in the optical element encapsulating casing structure of the present invention, the optical element is fixed to a pedestal on the lower surface of the lid, and a pair of side surfaces of the casing main body. An optical fiber end is inserted from the outside to the inside of the housing body through each through hole of the wall, and each of the optical fiber ends is passed through a sealing sleeve. The gap between the optical fiber holding member and the optical fiber holding member is hermetically sealed with a sealing material, and the end portion of the optical fiber extending from the sleeve is passed through the through hole of the optical fiber holding member on the lower surface of the lid body. The end of the optical fiber that has passed through the through hole is connected to the end of the optical element, and the sleeve that seals the end of the optical fiber is inserted into the through hole of the side wall of the housing body, This is hermetically sealed, and the lid is attached to the open upper surface of the housing body. This is hermetically sealed Te, is intended to include that.

Further, according to the method of the present invention for mounting an optical element and an optical fiber on an optical element encapsulating casing structure having an electrode mounting means, the optical element is fixed to a pedestal under the lid, and An optical element control electrode that is connected to an external power source is attached, the connection path between the electrode and the external power source is hermetically sealed, and the outside of the housing body is passed through each of the through holes of the pair of side wall portions. From the inside toward the inside of the housing body, insert each of the optical fiber ends into a sealing sleeve, and seal the gap between the sleeve and the optical fiber end with a sealing material. Stop, the optical fiber end portion extending from the sleeve, through the through hole of the optical fiber holding member on the lower surface of the lid, the optical fiber end portion through the through hole of the optical fiber holding member, Connect to the end of the optical element, connect the end of the optical fiber The sleeve that has been stopped is inserted into the through hole of the side wall portion of the housing body to hermetically seal it, and the lid is attached to the open upper surface of the housing body to hermetically seal it. It is to include sealing.

In the optical fiber used in the mounting method of the present invention described above, the bare optical fiber is exposed at the end portion connected to the end portion of the optical element at the end portion thereof, and the optical fiber holding of the lid body is held. It is preferable that the coating layer is formed on the bare optical fiber in the intermediate portion passing through the through hole of the member, and the bare fiber surface is metalized at the root portion passing through the sleeve.

[0015]

FIG. 1 shows an example of a conventional optical element sealing casing structure. In FIG. 1, a housing structure 1 is composed of a box-shaped housing body 2 and a lid body 3. The housing body 2 is provided with a bottom wall portion 4, a front wall portion 5 and a wall surface facing the bottom wall portion 4. Rear wall portion 6 and a pair of side wall portions 7 connecting them.
a and 7b, and only the upper surface 8 is open. The lid 3 closes the open upper surface 8 of the housing body 2.

In FIG. 1, an optical element fixing mount (bed) 9 is provided on the back wall portion 6 and the bottom wall portion 4 of the housing body 2, and the optical element 10 is fixed on this mounting base 9. There is. To both ends of the optical element 10 on the gantry 9, the ends of the bare optical fibers 12a and 12b at the ends of the optical fibers 11a and 11b are connected.

The optical fibers 11a and 11b are the housing body 2
Is pulled out of the housing through an optical fiber drawing bush 13a inserted into a through hole (not shown) provided in the side wall portions 7a, 7b of the optical fiber, and is hermetically sealed by the optical fiber drawing bush. There is.

When the optical element is an optical waveguide type optical element and an optical signal passing through the optical element is controlled by electrodes, the electrode lead 14 is attached to the optical element 10 and the electrode lead 1
4 is connected to an external power source (not shown) through a connection hole (not shown), and the connection hole is sealed with a sealant (solder or adhesive).

As described above, after the optical element and the optical fiber are mounted in the housing body 2, they are closed and sealed by the open upper surface or the lid 3.

In the conventional case structure shown in FIG. 1, as shown in FIG. 2, the mounting of optical fibers, electrodes, optical elements, etc. must be operated from the open upper surface of the case body. I have to. In FIG. 2, in order to connect the end face of the bare optical fiber 12a at the end of the optical fiber to the optical element 10 fixed on the pedestal 9, the bare optical fiber 12a is connected by the fiber chuck 15 of the position fine adjustment jig. Grasp and perform required fine adjustment of the position. At this time, it is possible to operate only on the open upper surface 8 of the conventional housing body 2 shown in FIG. 2, and the swing width A of the fiber chuck 15, that is, the degree of freedom of operation, is extremely limited. Become.

One embodiment of the housing structure of the present invention is shown in FIG. In FIG. 3, the housing structure 21 of the present invention
Is composed of a metal box-shaped housing body 22 and a metal lid body 23. The housing body 22 includes a bottom wall portion 24 and a front wall portion 2.
5, a back wall portion 26, and a pair of side wall portions 27a and 27b facing each other that connect them in a box shape, an upper surface 28 thereof is opened, and this upper surface is sealed and closed by a lid 23. .

A through hole 29 for passing an optical fiber is formed in the side wall of the housing body 22.

The lid 23 may be a flat plate-like body as shown in FIG.
On the lower surface 30 that closes the open upper surface 28, a pedestal 31
Is provided and the optical element 32 is fixed thereon.
The gantry 31 may be formed integrally with the lid 23, or may be joined by welding, brazing, or the like. Both ends of the optical element 32 are connected to the tips of the bare optical fibers 34a, 34b exposed at the tip ends of the optical fibers 33a, 33b through connecting jigs (capillaries) 35a, 35b.

On the lower surface 30 of the lid 23, optical fiber holding members 36a and 36b are projected on both sides of the pedestal 31, and the holding members 36a and 36b are provided with through holes 37a for penetrating the optical fiber tips. , 37b are formed, and the end of the optical fiber passing through the through holes 37a, 37b is
It may or may not be adhered and fixed by the adhesive injected into the through hole. Holding member 36
The a and 36b may be molded integrally with the lid body 23, or may be joined by welding, brazing, or the like.

The ends of the optical fibers 33a and 33b extending outward from the holding members 36a and 36b are passed through the optical fiber sealing sleeves 38a and 38b. The sleeves 38a, 38b have through holes 39 for inserting optical fibers, and sleeve cores 40a, 40b for inserting the optical fibers 33a, 33b are inserted therein. That is, FIG.
In, the portions of the optical fibers 33a and 33b having the coating layer are inserted into the sleeve cores 40a and 40b, and the sleeve cores 40a and 40b are inserted into the through holes of the sleeve. In addition, the optical fiber 33a in the through hole 39,
The portion of the coating 33b from which the coating layer is removed is the sealing agent injection hole 41.
It is sealed and fixed in the through hole 39 by the sealant injected from.

The end portions of the optical fiber joined to both ends of the optical element as described above have through holes 29 in the side wall portions 27a and 27b.
And the sleeves 38a and 37b are pulled out from the through hole 2
9 and is sealed.

A connector 43 for an electrode for applying an electric signal to the optical element is attached to the lid 23, and an electrode connector sealant injection hole 42 is provided in the pedestal 31 to penetrate the lid 23. The central lid part of the connector is
An electrode (not shown), which is inserted into a connector insertion hole (not shown) of the pedestal and arranged with respect to the optical element on the pedestal 31, can be connected to an external power source (not shown), The connector insertion hole is the sealant injection hole 42.
It is sealed by the injected sealing agent (solder).

In order to mount the optical element and the end portion of the optical fiber on the housing structure by the method of the present invention, in FIG.
The optical element 32 is fixed on a pedestal 31 provided on the lower surface 30 of the lid 23 with, for example, a conductive epoxy adhesive. Separately, the coating layers at the ends of the pair of optical fibers 33a and 33b are removed to expose the bare optical fibers 34a and 34b, and the required portions thereof are subjected to a melatizing treatment.

The end portions 33a and 33b of this optical fiber are
From the outside of the housing body 22, the side wall portions 27a, 27b thereof
It is introduced into the housing main body 22 through the through hole 29 and is passed through the through hole 39 of the sleeves 38a and 38b. At this time, the ends of the optical fiber ends 33a, 33b having the coating layer are passed through the cores 40a, 40b of the sleeves 38a, 38b,
This may be inserted into the through hole 39 of the sleeves 38a and 38b. Then, the through holes 3 in the sleeves 38a and 38b.
9 is a portion having a coating layer of the optical fibers 33a and 33b,
The part from which it was removed will be inserted. Through hole 3
The optical fiber in 9 is hermetically sealed by the sealant injected from the sealant injection hole 41.

Next, the bare optical fiber 34 at the end of the optical fiber
The a and 34b are passed through the through holes 37a and 37b of the optical fiber holding members 36a and 36b. When the end surface of the bare optical fiber is bonded to the end surface of the optical element, the through holes 37a and 37b of the holding members 36a and 36b are set to be sufficiently larger than the diameters of the bare optical fibers 34a and 34b for adjusting the optical axis thereof. If it is necessary (for example, a work space for freely displacing the position of the bare optical fiber, or a space for working while observing the end face of the optical element from the front), the bare optical fiber 34a, 34b, core 37
c, 37d, and after the above work, the core 37d,
37d may be inserted into the through holes 37a and 37b to close them. The holding members 36a and 36b and the bare optical fibers 34a and 34b passing through the holding members 36a and 36b do not need to be adhesively fixed to each other.

Next, the tip surfaces of the bare optical fibers 34a and 34b are, if necessary, adhered and strengthened (capillaries) 35a,
The optical axis is adjusted and adhered and fixed to the end surface of the optical element via 35b. That is, the bare optical fibers 34a and 34b are supported at two places by the adhesive fixing end surface and the holding members 36a and 36b.

When the optical element is an optical waveguide type optical element and is controlled by an electrode with an optical signal passing through the optical element, the electrode connector 43 is attached to the lid body 23, and the electrode connector 43 is inserted through the electrode connector insertion hole 42 of the mount 32. To an electrode (not shown) arranged on the optical element. At this time, the electrode and the central conductor of the connector are connected by an ultrasonic bonding method or a bonding agent such as indium.

Next, the optical fibers 33a and 33b are pulled out to the outside through the through holes 29 of the case body side wall portions 27a and 27b, and the lid portion 23 is overlapped on the open upper surface of the case body 22, while the sleeve 38a, 38b is inserted into the through hole 29 to seal it. In the above operation, since the bare optical fibers 34a and 34b are held by the holding members 36a and 36b, they are not bent or broken, and the end face of the bare optical fiber and the end face of the optical element are separated from each other. There is no such thing.

The sleeve 38 mounted on the housing body 22
The a and 38b are sealed by soldering or welding, and the housing body 22 and the lid 23 are sealed by soldering or seam welding. That is, when sealing the housing structure containing the optical element and the optical fiber in an airtight manner, a commonly used seam welding method can be used for joining the metal housing body and the lid body. Welding or soldering may be used to join the body and the sleeve made of metal.

The end of the optical fiber connected to the end of the optical element preferably has a structure as shown in FIG. 4, for example. In FIG. 4, the optical fiber 44 includes a bare optical fiber 45, a primary coating layer 46 that covers the bare optical fiber 45, and a secondary coating layer 47 that covers the bare optical fiber 45. The coating layers 46 and 47 at the ends of the optical fiber 44. Have been removed. That is, the end of the optical fiber is connected to the end face of the optical element at the exposed end face 48 of the bare optical fiber 45.

The intermediate portion 49 of the bare optical fiber of the optical fiber 44, which passes through the through hole of the optical fiber holding member and is held by this, is preferably recoated with a material such as an ultraviolet curable resin. In this way, the surface of the bare optical fiber is not damaged and is properly held by the holding member. Further, the root portion 50 that is passed through the sleeve through hole at the end of the bare optical fiber is metalized (eg, gold plated).
It is preferable that With this arrangement, when the solder is injected into the sleeve through hole and is sealed, the solder and the surface of the bare optical fiber are firmly adhered, and the sleeve through hole can be completely sealed. Further, since reliability of mechanical strength is low only by fixing the solder at the root portion 50 of the bare optical fiber, if necessary, a portion of the protective coating layer of the optical fiber may be passed through the sleeve core in advance to protect the optical fiber. The protective coating portion may be fixed by crimping by inserting the core through the coating portion into the sleeve. The same effect can be obtained by injecting an adhesive into the gap between the sleeve and the fiber coating instead of using the core instead of pressure fixing.

[0037]

According to the present invention, the optical element and the optical fiber can be mounted on the housing structure easily and with high reliability.

[Brief description of drawings]

FIG. 1 is a perspective explanatory view showing a configuration of a conventional optical element sealed casing structure.

FIG. 2 is a cross-sectional explanatory view showing a degree of freedom in operating a fiber chuck of a jig for finely adjusting the position of a bare optical fiber in a conventional casing structure.

FIG. 3 is a perspective explanatory view showing a configuration and a mounting method of a casing structure of the present invention.

FIG. 4 is a front explanatory view showing an example of the configuration of an end portion of an optical fiber mounted on the housing structure of the present invention.

[Explanation of symbols]

 1, 21 ... Casing structure 2, 22 ... Casing body 3,23 ... Lid 4,24 ... Bottom wall 5,25 ... Front wall 6,26 ... Back wall 7a, 7b, 27a, 27b ... Side wall portion 8, 28 ... Open upper surface 9, 31 ... Frame 10, 32 ... Optical element 11a, 11b, 33a, 33b ... Optical fiber 12a, 12b, 34a, 34b ... Naked optical fiber 13a, 13b ... Optical fiber drawing bush 14 ... Electrode lead 15 ... Fiber chuck of optical fiber position fine adjustment jig A ... Swing width of fiber chuck 29 ... Side wall through hole 30 ... Lid lower surface 35a, 35b ... Connection jig 36a, 36b ... Optical fiber holding member 37a , 37b ... Holding member through hole 37c, 37d ... Holding member core 38a, 38b ... Sleeve 39 ... Through hole 49a, 40b ... Core 41 ... Sealant injection hole 42 ... Electrode connection Over the sealing agent injection hole 43 ... electrode connector 44 ... optical fiber 45 ... bare optical fiber 46 ... primary coating layer 47 ... secondary coating layer 48 ... end surface 49 ... recoating layer 50 ... metallization

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mitsuru Sakuma 585 Tomicho, Funabashi, Chiba Sumitomo Cement Corporation Central Research Laboratory

Claims (5)

[Claims] 1. A container for accommodating and sealing an optical element and an end portion of an optical fiber connected to the optical element, the main body having a box shape with an open upper surface, and a lid for closing the open upper surface. The housing body has a through hole for penetrating an end of the optical fiber connected to the optical element, and a pair of sleeves for hermetically sealing the through hole are attached. Having side wall surface portions facing each other, on the lower surface of the lid body facing the housing body, a pedestal for fixing the optical element, and arranged on both sides of the pedestal,
A pair of optical fiber holding members having a through hole for penetrating an end of the optical fiber connected to the optical element, and a pair of optical fiber holding members are arranged. 2. The optical element is an optical waveguide type optical element, and an electrode for controlling the optical element by an electric signal is provided on the lid and an optical element mount arranged on the lower surface thereof. The housing structure according to claim 1, further comprising mounting means. 3. When mounting an optical element and an optical fiber on the optical element sealing casing structure according to claim 1, the optical element is fixed to a pedestal on the lower surface of the lid, and Through each through hole of the pair of side wall parts,
Insert the optical fiber end portion from the outside toward the inside of the housing body, pass each of the optical fiber end portions through a sealing sleeve, and seal the gap between the sleeve and the optical fiber end portion with a sealing material. The end of the optical fiber extending from the sleeve is penetrated through the through hole of the optical fiber holding member on the lower surface of the lid, and the end of the optical fiber passing through the through hole of the optical fiber holding member. Is connected to the end of the optical element, the sleeve that seals the end of the optical fiber is inserted into the through hole of the side wall of the housing body, and this is hermetically sealed, and A method for mounting a casing structure for encapsulating an optical element, comprising mounting the lid on an open upper surface of the casing body and hermetically sealing the lid. 4. When mounting an optical element and an optical fiber on the optical element encapsulating casing structure according to claim 2, the optical element is fixed to a pedestal on the lower surface of the lid, and an external power source is attached to the optical element. An optical element control electrode to be connected to, a hermetically sealing the connection path between the electrode and an external power source, through each through hole of a pair of side wall portions of the housing body,
Insert the optical fiber end portion from the outside toward the inside of the housing body, pass each of the optical fiber end portions through a sealing sleeve, and seal the gap between the sleeve and the optical fiber end portion with a sealing material. The end of the optical fiber extending from the sleeve is penetrated through the through hole of the optical fiber holding member on the lower surface of the lid, and the end of the optical fiber passing through the through hole of the optical fiber holding member. Is connected to the end of the optical element, the sleeve that seals the end of the optical fiber is inserted into the through hole of the side wall of the housing body, and this is hermetically sealed, and A method for mounting a casing structure for encapsulating an optical element, comprising mounting the lid on an open upper surface of the casing body and hermetically sealing the lid. 5. A bare optical fiber is exposed at a tip end portion of the optical fiber end portion connected to the optical element end portion, and an intermediate portion passing through a through hole of an optical fiber holding member of the lid body. The mounting method according to claim 4 or 5, wherein a coating layer is formed on the bare optical fiber, and the bare fiber surface is metallized at a root portion passing through the sleeve.