CA2259971A1 - Method for making a hermetically sealed package comprising at least one optical fibre feedthrough - Google Patents
Method for making a hermetically sealed package comprising at least one optical fibre feedthrough Download PDFInfo
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- CA2259971A1 CA2259971A1 CA002259971A CA2259971A CA2259971A1 CA 2259971 A1 CA2259971 A1 CA 2259971A1 CA 002259971 A CA002259971 A CA 002259971A CA 2259971 A CA2259971 A CA 2259971A CA 2259971 A1 CA2259971 A1 CA 2259971A1
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- Prior art keywords
- fibre
- solder
- package
- fibres
- sealing
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Classifications
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/24—Coupling light guides
- G02B6/42—Coupling light guides with opto-electronic elements
- G02B6/4201—Packages, e.g. shape, construction, internal or external details
- G02B6/4248—Feed-through connections for the hermetical passage of fibres through a package wall
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/24—Coupling light guides
- G02B6/36—Mechanical coupling means
- G02B6/3628—Mechanical coupling means for mounting fibres to supporting carriers
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Light Guides In General And Applications Therefor (AREA)
Abstract
The invention pertains to a very efficient method for making a hermetically sealed package, which package comprises a housing (1), a lid (2), and a feedthrough for at least one stripped optical fibre (4), which method comprises the following steps: placing the optical fibre or fibres and at least one solder preform (3) between the sealing surface of the lid and the sealing surface of the housing; sealing the assembly by applying pressure and heat so as to press the fibre or fibres into the solder.
Description
METHOD FOR MAKING A HERMETICALLY SEALED PACKAGE
COMPRISING AT LEAST ONE OPTICAL FIBRE FEEDTHROUGH
The invention pertains to a method for making a hermetically sealed 5 package, which package comprises a housing, a lid, and a feedthrough for at least one stripped optical fibre.
Such a method is known from US 4,779,788. The method disclosed in this publication involves feeding an optical fibre through a hole in one of the 10 metal walls of the package. Subsequently, excess solder in a molten state is provided outside the hole to form a solder body surrounding and adhering to the optical fibre. The solder body is also connected with the outside of the metal housing and with at least part of the length of the wall of the hole. During cooling the molten solder shrinks and the free surface of 1~ the solder body also shrinks under the influence of surface tension. The solder is drawn towards the hole and onto and around the glass fibre, thus hermetically sealing in the fibre.
It is common practice to use an array of optical fibres instead of one single 20 fibre. An array of, e.g., seven optical fibres requires the making of at least seven holes and seven hermetical feedthroughs, for instance by the method disclosed in US 4,779,788. Accordingly, the process for manufacturing fiat packages is complicated and expensive. Not surprisingly, the hermetical feedthroughs are responsible for the greater 25 part of the total costs involved in said manufacturing process.
US 5,061,03~ concerns a method for making a hermetically sealed fibre array comprising a bundle of optical fibres provided with a solderable metal coating (preferably nickel and gold) to ensure adhesion to a solder. The 30 optical fibre bundle is placed in a supporting structure having a front face CA 022~9971 1998-12-30 k~A/L~I~)/()kti ~ wi i!~ 11i: Iti~ 3~ '1 1/+:31 1() :3t():3111~ 3 ~?
AEM 2534 ~
.
and a coatedinnersu~ace sothatthe end face ofthe opt~calfibre bundle i8 flush wi~ the front face of the supporting 4tluctute. The assembly is then heated and fluxless solder ia applied to the end face and allowed to wick ' _h~cen the individual fibre~ and the inner !lurface of the support. Prefer~bly~
the solder is sucked in by means of a vacuum on the back face of the supporting structure.
US 4,174,4g1 relates to a method in which a mehllised optical fibre is placed in a groove in a mount substrate. A keeper subsbte which is alsc providsd with a ~r~ove is placed on top of the rnount substrate 80 that the grooves snusly ho~i the opticàl fibre. The groov~d substr~tes are weldeci to~ether by means of a 301der coabng provided on their grooved ~rfaces. Subsequentty, the i~lt~ r~.ace behNeen the optical fibre and the -~ubsllt.les is fllled up with a low fusin~ solder.
DE 28 2g 548 dis~loses the deposition o~ a thin layer of indium and le~d on both an upper and a lo~er substrate~s surf~ce. These layers are used to we!d the said YU~ dl~ together. A~er this welding step, a 11~ is h~ etically welded onto the ~pper subetrats, The assembly further comprise6 an optical flbre which is ~ed throu~h ~rooYes in the upper and lower substrates. Anar sealin~ of tho lid, the ~pace bet~r~e~n the optical fi~re on the one hand and the upper and lower substrates on ~he other hand is fille~ up with a low fusing solder.
US 5,412,748 discloses a similar Illcthod. A fibre re~Jll~ gh betvJ~en a cap ~nd a ~ubmount Is hermetlcally sealed in a separate process step after the cap h~s been ~old~r~d to th~ submount. It is described how an auxiliary solder is used for fflllng the ~pace beh~een the optical fibre a~ci the cap. This auxiliary sealing solder ~an ~e formed by meltin~ a sclder havin~ a relatively low meltin~ point and inJecting the solder into the sap using a capillaly phenomenon.
~JIENDED SHEET
" 2a It is an object o~ the prcsu~t inver,~ion to provide a method for hei,netically ~ealins pac~ s which involve~ comp~ratively few and simple p,o~er~
steps. This object is achieved by the following process steps in the method describ!d in the first para~raph:
placing the optical fibre ~r ffbres and at least one solder preform between the sealin~ surface of the lid and the sealin~ surhce of the housing - scaling the as~embly, at le~st around Ule optlcal flbre or fibres, by applyin~ pre~ure and he~t ~o a8 to pre~s the fibre or nbr~s into the solder.
Wth thi~ n~t~lod, all t~le optic~l fibre~ in an array can be ~e~led simu~taneously in a very ef~icient and effective manner. The ~eam obtained A~NDF~ S~EET
with the method according to the invention is (practically) impervious to moisture and other gases and easily meets the current standards.
Further, the hermetic fibre feedthrough(s) can be formed using 5 conventional package housings or seal rings and lids and do(es) not require custom ferrules. The number of juxtaposed fibres in this type of feedthrough is limited only by the available package lid seam length and the fibre diameter.
10 A still further advantage of the present invention resides in the fact that welding or soldering the lid onto the housing is combined with making the fibre feedthroughs. Until now, attaching the lid to the housing and providing the fibre feedthrough were two separate processes.
15 Within the framework of the present invention the term "solder preform"
includes, amongst others, separate rings of solder (adapted to the shape of the lid and/or the shape of the opening in the package body or housing~
and relatively thick coatings on the lid sealing surface and/or the housing sealing surface. Said coating can, for instance, be achieved by reflowing 20 solder onto the sealing surface(s) using a proper flux.
The solder of which the preforms are made should have the property that it wets both the optical fibre or fibres and the sealing surfaces of the lid and the housing. Examples of suitable solders are indium, indium/silver, 25 indium/tin, and glass solder (ex Gould).
In order to further simplify the process and make an improved seam it is preferred to use more than one solder preform. Thus, a stack can be obtained comprising at least five elements, e.g., the package body or 30 housing, a first solder preform, the fibre or array of hbres, a second solder CA 022~997l l998-l2-30 preform, and the lid. Since the solder which is to form the seam is present on both sides of the fibre or fibres, it is easier to ensure that it reflows completely around the fibre or fibres. Thus, the chance of obtaining an end product not suitable for sale is reduced.
Irrespective of the number of solder preforms, it is preferred that the (total) thickness of the preform or preforms exceeds the diameter of the stripped fibre, preferably at least by 20 percent. Thus, a hermetic seal with solder both below and above the fibre is ensured even when both the sealing 10 surface of the lid and the sealing surface of the package body or housing are perfectly flat.
In a preferred embodiment, the optical fibre or fibres are solder coated prior to sealing the package. The solder used to precoat the fibres must have 15 the property that it wets glass in a molten state. In this respect, suitable solders are, e.g., indium, indium/silver, and indiumltin solders. With solders of this type, the precoating of the fibres can be accomplished by simply dipping the stripped section of the optical fibres into the molten solder.
20 As mentioned, the package is sealed through the application of heat and pressure. During this sealing step all or nearly all the voids between the solder and the fibre or fibres are eliminated. In the process according to the invention, it is also possible to apply additional heat after the sealing step, for instance, to further melt the solder and improve the continuity of the 25 solder seam between the package body, the lid, and the optical fibre or fibres.
Depending on the material used for the elements of the package, it can be advantageous to use an intermediate between the housing or the lid and 30 the solder preform or the fibres. For instance, if the housing is made of a CA 022~9971 1998-12-30 ceramic material, a metal sealing ring or brazing pad can be provided around the opening of the housing to enhance the adherence of the solder.
The person skilled in the art will have no diff~culty in selecting an appropriate combination of materials.
With the method according to the invention it is also possible to place a further solder preform on top of the fibre or fibres and a further layer comprising at least one fibre on top of said further solder preform. Thus, several layers containing at least one fibre each can be stacked one on top 10 of the other and sealed simultaneously.
The invention further pertains to a hermetically sealed package obtainable by the method as described above, which package comprises a housing or package body and a lid (preferably both having a fiat sealing surface) 15 sealed onto it by means of a continuous solder seam, through which solder seam at least one fibre is fed.
This package allows very efficient manufacture, is inexpensive, and does not require custom ferrules or the like. Also, the width of a fibre array 20 feedthrough can be made ver,v small (because ferrules or grooves are not necessary), thus reducing the package size in the dimension of the array.
It should be noted that JP 63 085505 concerns a method for welding and fixing optical fibres into V-grooves formed on a substrate. Heating elements 25 consisting of a high resistance material are deposited into the grooves and, in turn, a "low melting metal" such as a solder is plated on the heating elements. The optical fibres are coated with a welding metal such as gold and placed in the grooves. During subsequent heating by means of the heating elements, a plate is pressed onto the fibres and the "low melting CA 022~9971 1998-12-30 metal" is melted. Thus, the optical fibres are adhered to the metal. A
hermetically sealed package is not disclosed.
Figure 1 shows schematically an assembly according to the invention just 5 prior to the application of heat and pressure. The assembly comprises a package body or housing 1, a lid 2, two solder preforms 3, and an array 4 consisting of seven individually precoated optical fibres.
Figure 2 shows the assembly of Figure 1 after the application of heat and 10 pressure The solder preforms 3 have formed a continuous solder seam 5.
The invention will now be illustrated by way of a further, more detailed example. As a matter of course, the invention is in no way restricted to this example.
Examples Hermetically sealed packages with up to 9 fibre feedthroughs were made 20 with the process described below. The packages had a single fibre feedthrough at the input side and a fibre array feedthrough containing as many as 8 fibres on the output side. All of the package housings described hereinbelow were made of alumina and had gold over nickel plated Kovar seal rings brazed onto gold plated pads on the package sealing surface.
25 The lids were also made of Kovar with gold over nickel plating. The optical fibres were all Corning SMF-28. Pure indium was used as the solder to make the seals. The fibre feedthrough fabrication and package sealing process was comprised of the following steps:
30 1. Indium was applied to the top surface of the package seal ring and to the sealing surface of the lid by first coating the sealing surfaces with a thin CA 022~9971 1998-12-30 layer of flux. Indium rings, each 0.010" thick, were then pressed onto the flux layers. The package bodies and lids were placed in a nitrogen purged reflow oven and heated until the indium melted and completely wetted the sealing surfaces. The package bodies and the lids were 5 allowed to cool to near room temperature in the oven. Flux residues were removed from the coated sealing surfaces in an isopropanol bath.
COMPRISING AT LEAST ONE OPTICAL FIBRE FEEDTHROUGH
The invention pertains to a method for making a hermetically sealed 5 package, which package comprises a housing, a lid, and a feedthrough for at least one stripped optical fibre.
Such a method is known from US 4,779,788. The method disclosed in this publication involves feeding an optical fibre through a hole in one of the 10 metal walls of the package. Subsequently, excess solder in a molten state is provided outside the hole to form a solder body surrounding and adhering to the optical fibre. The solder body is also connected with the outside of the metal housing and with at least part of the length of the wall of the hole. During cooling the molten solder shrinks and the free surface of 1~ the solder body also shrinks under the influence of surface tension. The solder is drawn towards the hole and onto and around the glass fibre, thus hermetically sealing in the fibre.
It is common practice to use an array of optical fibres instead of one single 20 fibre. An array of, e.g., seven optical fibres requires the making of at least seven holes and seven hermetical feedthroughs, for instance by the method disclosed in US 4,779,788. Accordingly, the process for manufacturing fiat packages is complicated and expensive. Not surprisingly, the hermetical feedthroughs are responsible for the greater 25 part of the total costs involved in said manufacturing process.
US 5,061,03~ concerns a method for making a hermetically sealed fibre array comprising a bundle of optical fibres provided with a solderable metal coating (preferably nickel and gold) to ensure adhesion to a solder. The 30 optical fibre bundle is placed in a supporting structure having a front face CA 022~9971 1998-12-30 k~A/L~I~)/()kti ~ wi i!~ 11i: Iti~ 3~ '1 1/+:31 1() :3t():3111~ 3 ~?
AEM 2534 ~
.
and a coatedinnersu~ace sothatthe end face ofthe opt~calfibre bundle i8 flush wi~ the front face of the supporting 4tluctute. The assembly is then heated and fluxless solder ia applied to the end face and allowed to wick ' _h~cen the individual fibre~ and the inner !lurface of the support. Prefer~bly~
the solder is sucked in by means of a vacuum on the back face of the supporting structure.
US 4,174,4g1 relates to a method in which a mehllised optical fibre is placed in a groove in a mount substrate. A keeper subsbte which is alsc providsd with a ~r~ove is placed on top of the rnount substrate 80 that the grooves snusly ho~i the opticàl fibre. The groov~d substr~tes are weldeci to~ether by means of a 301der coabng provided on their grooved ~rfaces. Subsequentty, the i~lt~ r~.ace behNeen the optical fibre and the -~ubsllt.les is fllled up with a low fusin~ solder.
DE 28 2g 548 dis~loses the deposition o~ a thin layer of indium and le~d on both an upper and a lo~er substrate~s surf~ce. These layers are used to we!d the said YU~ dl~ together. A~er this welding step, a 11~ is h~ etically welded onto the ~pper subetrats, The assembly further comprise6 an optical flbre which is ~ed throu~h ~rooYes in the upper and lower substrates. Anar sealin~ of tho lid, the ~pace bet~r~e~n the optical fi~re on the one hand and the upper and lower substrates on ~he other hand is fille~ up with a low fusing solder.
US 5,412,748 discloses a similar Illcthod. A fibre re~Jll~ gh betvJ~en a cap ~nd a ~ubmount Is hermetlcally sealed in a separate process step after the cap h~s been ~old~r~d to th~ submount. It is described how an auxiliary solder is used for fflllng the ~pace beh~een the optical fibre a~ci the cap. This auxiliary sealing solder ~an ~e formed by meltin~ a sclder havin~ a relatively low meltin~ point and inJecting the solder into the sap using a capillaly phenomenon.
~JIENDED SHEET
" 2a It is an object o~ the prcsu~t inver,~ion to provide a method for hei,netically ~ealins pac~ s which involve~ comp~ratively few and simple p,o~er~
steps. This object is achieved by the following process steps in the method describ!d in the first para~raph:
placing the optical fibre ~r ffbres and at least one solder preform between the sealin~ surface of the lid and the sealin~ surhce of the housing - scaling the as~embly, at le~st around Ule optlcal flbre or fibres, by applyin~ pre~ure and he~t ~o a8 to pre~s the fibre or nbr~s into the solder.
Wth thi~ n~t~lod, all t~le optic~l fibre~ in an array can be ~e~led simu~taneously in a very ef~icient and effective manner. The ~eam obtained A~NDF~ S~EET
with the method according to the invention is (practically) impervious to moisture and other gases and easily meets the current standards.
Further, the hermetic fibre feedthrough(s) can be formed using 5 conventional package housings or seal rings and lids and do(es) not require custom ferrules. The number of juxtaposed fibres in this type of feedthrough is limited only by the available package lid seam length and the fibre diameter.
10 A still further advantage of the present invention resides in the fact that welding or soldering the lid onto the housing is combined with making the fibre feedthroughs. Until now, attaching the lid to the housing and providing the fibre feedthrough were two separate processes.
15 Within the framework of the present invention the term "solder preform"
includes, amongst others, separate rings of solder (adapted to the shape of the lid and/or the shape of the opening in the package body or housing~
and relatively thick coatings on the lid sealing surface and/or the housing sealing surface. Said coating can, for instance, be achieved by reflowing 20 solder onto the sealing surface(s) using a proper flux.
The solder of which the preforms are made should have the property that it wets both the optical fibre or fibres and the sealing surfaces of the lid and the housing. Examples of suitable solders are indium, indium/silver, 25 indium/tin, and glass solder (ex Gould).
In order to further simplify the process and make an improved seam it is preferred to use more than one solder preform. Thus, a stack can be obtained comprising at least five elements, e.g., the package body or 30 housing, a first solder preform, the fibre or array of hbres, a second solder CA 022~997l l998-l2-30 preform, and the lid. Since the solder which is to form the seam is present on both sides of the fibre or fibres, it is easier to ensure that it reflows completely around the fibre or fibres. Thus, the chance of obtaining an end product not suitable for sale is reduced.
Irrespective of the number of solder preforms, it is preferred that the (total) thickness of the preform or preforms exceeds the diameter of the stripped fibre, preferably at least by 20 percent. Thus, a hermetic seal with solder both below and above the fibre is ensured even when both the sealing 10 surface of the lid and the sealing surface of the package body or housing are perfectly flat.
In a preferred embodiment, the optical fibre or fibres are solder coated prior to sealing the package. The solder used to precoat the fibres must have 15 the property that it wets glass in a molten state. In this respect, suitable solders are, e.g., indium, indium/silver, and indiumltin solders. With solders of this type, the precoating of the fibres can be accomplished by simply dipping the stripped section of the optical fibres into the molten solder.
20 As mentioned, the package is sealed through the application of heat and pressure. During this sealing step all or nearly all the voids between the solder and the fibre or fibres are eliminated. In the process according to the invention, it is also possible to apply additional heat after the sealing step, for instance, to further melt the solder and improve the continuity of the 25 solder seam between the package body, the lid, and the optical fibre or fibres.
Depending on the material used for the elements of the package, it can be advantageous to use an intermediate between the housing or the lid and 30 the solder preform or the fibres. For instance, if the housing is made of a CA 022~9971 1998-12-30 ceramic material, a metal sealing ring or brazing pad can be provided around the opening of the housing to enhance the adherence of the solder.
The person skilled in the art will have no diff~culty in selecting an appropriate combination of materials.
With the method according to the invention it is also possible to place a further solder preform on top of the fibre or fibres and a further layer comprising at least one fibre on top of said further solder preform. Thus, several layers containing at least one fibre each can be stacked one on top 10 of the other and sealed simultaneously.
The invention further pertains to a hermetically sealed package obtainable by the method as described above, which package comprises a housing or package body and a lid (preferably both having a fiat sealing surface) 15 sealed onto it by means of a continuous solder seam, through which solder seam at least one fibre is fed.
This package allows very efficient manufacture, is inexpensive, and does not require custom ferrules or the like. Also, the width of a fibre array 20 feedthrough can be made ver,v small (because ferrules or grooves are not necessary), thus reducing the package size in the dimension of the array.
It should be noted that JP 63 085505 concerns a method for welding and fixing optical fibres into V-grooves formed on a substrate. Heating elements 25 consisting of a high resistance material are deposited into the grooves and, in turn, a "low melting metal" such as a solder is plated on the heating elements. The optical fibres are coated with a welding metal such as gold and placed in the grooves. During subsequent heating by means of the heating elements, a plate is pressed onto the fibres and the "low melting CA 022~9971 1998-12-30 metal" is melted. Thus, the optical fibres are adhered to the metal. A
hermetically sealed package is not disclosed.
Figure 1 shows schematically an assembly according to the invention just 5 prior to the application of heat and pressure. The assembly comprises a package body or housing 1, a lid 2, two solder preforms 3, and an array 4 consisting of seven individually precoated optical fibres.
Figure 2 shows the assembly of Figure 1 after the application of heat and 10 pressure The solder preforms 3 have formed a continuous solder seam 5.
The invention will now be illustrated by way of a further, more detailed example. As a matter of course, the invention is in no way restricted to this example.
Examples Hermetically sealed packages with up to 9 fibre feedthroughs were made 20 with the process described below. The packages had a single fibre feedthrough at the input side and a fibre array feedthrough containing as many as 8 fibres on the output side. All of the package housings described hereinbelow were made of alumina and had gold over nickel plated Kovar seal rings brazed onto gold plated pads on the package sealing surface.
25 The lids were also made of Kovar with gold over nickel plating. The optical fibres were all Corning SMF-28. Pure indium was used as the solder to make the seals. The fibre feedthrough fabrication and package sealing process was comprised of the following steps:
30 1. Indium was applied to the top surface of the package seal ring and to the sealing surface of the lid by first coating the sealing surfaces with a thin CA 022~9971 1998-12-30 layer of flux. Indium rings, each 0.010" thick, were then pressed onto the flux layers. The package bodies and lids were placed in a nitrogen purged reflow oven and heated until the indium melted and completely wetted the sealing surfaces. The package bodies and the lids were 5 allowed to cool to near room temperature in the oven. Flux residues were removed from the coated sealing surfaces in an isopropanol bath.
2. Both the input single fibres and the output fibre arrays were also coated with indium prior to package sealing. This was done by first stripping off 10 the acrylate coating from the sections of the fibres or fibre arrays that would be sealed into the indium package/lid seam. The exposed silica surfaces of the fibres were cleaned with isopropanol and lens tissue and then blown dry. The cleaned portions were then slowly passed back and forth through molten indium on a glass stage which was heated from the 15 bottom by a heated brass block and from the top by a heating element dipped into the indium. For the fibre arrays, the fibres were maintained in a linear array by external clamps. ~ stream of nitrogen was directed over and around the molten indium. After being in the molten indium for about 30 seconds (about 2 or 3 passes), the fibres or hbre arrays were 20 removed and allowed to cool.
3. The fibre feedthroughs were formed by first positioning the indium coated sections of the fibres or fibre arrays over the package seai ring at the input and output locations and then holding them in place with 25 external clamps. Next, the lid was positioned directly above the package seal ring and held in place by external guides. Heat and pressure were then applied to the input and output ends of the lids until the indium on the lid, then on the fibres, and hnally on the package seal ring melted and flowed together to form a continuous indium seal between the seal CA 022~9971 1998-12-30 ring and the lid and around the fibres. The heat was removed and the lid was held in place until the indium had frozen.
4. Except for a short, less than 1 cm long, section, all of the remaining 5 sections of the packagellid seal were then formed using a similar application of heat and pressure. The short section was left unsealed to facilitate the bakeout of water and other volatiles from the package interior.
10 5. Bakeout of the package assembly was carried out under vacuum at 100~C for 14 hours.
10 5. Bakeout of the package assembly was carried out under vacuum at 100~C for 14 hours.
6. After bakeout, the package assembly was allowed to cool and was then transported directly into a nitrogen purged dry box. The package sealing 15 was completed by applying heat and pressure to the remaining unsealed section until the indium on the lid and on the package seal ring melted and flowed together to form a continuous indium seal between the seal ring and the lid.
20 Sectioning of 8-fibre feedthroughs sealed with the above process clearly shows that the fibres are completely surrounded by indium and that the indium completely fills the space between the package and the lid.
Packages having a 1-fibre input feedthrough and an 8-fibre output feedthrough sealed with the above procedure have been helium leak tested 25 and then subjected to a number of environmental stress tests before being leak tested again. The leak rates measured before and after the environmental stress tests were all under the 1 x 10E-6 atm-cc/sec air equivalent standard leak rate limit specified by MIL-STD-883 for hermetic packages of the size sealed. These tests, and the associated package 30 counts, include:
CA 022~9971 1998-12-30 W O 98/01783 PCT/~P97103492 Low Temperature Storage (-40~C), 92û hours: Two packages.
High Temperature Storage (71~C), 600 hours: Two packages.
Temperature Cycling (-40 to 7Q~C, 20 cycles/day), 120 cycles: Three packages.
Thermal Shock (0 to 100~C in water baths, 2 minutes per bath), 15 cycles:
Five packages.
RGA has also been carried out on similar packages after sealing and after 15 cycles of 0 to 100~C thermal shock in water baths. The measured water content was under the 5000 ppm limit specified by MIL-STD-883 for hermetic packages. These results clearly show that the process described above simultaneously forms robust hermetic seals around the optical fibres and between the package and the lid.
1~ Optical transmission and return loss measurements have been carried out at 1.53 ~Lm on fibre feedthroughs made with the above process. The loss per feedthrough was less than 0.05 dB. No return peaks above -70 dB
were observed in CDR scans. The fibre sealing process described above, therefore, does not result in any cracking or microbending of the fibres.
CA 022~9971 1998-12-30
20 Sectioning of 8-fibre feedthroughs sealed with the above process clearly shows that the fibres are completely surrounded by indium and that the indium completely fills the space between the package and the lid.
Packages having a 1-fibre input feedthrough and an 8-fibre output feedthrough sealed with the above procedure have been helium leak tested 25 and then subjected to a number of environmental stress tests before being leak tested again. The leak rates measured before and after the environmental stress tests were all under the 1 x 10E-6 atm-cc/sec air equivalent standard leak rate limit specified by MIL-STD-883 for hermetic packages of the size sealed. These tests, and the associated package 30 counts, include:
CA 022~9971 1998-12-30 W O 98/01783 PCT/~P97103492 Low Temperature Storage (-40~C), 92û hours: Two packages.
High Temperature Storage (71~C), 600 hours: Two packages.
Temperature Cycling (-40 to 7Q~C, 20 cycles/day), 120 cycles: Three packages.
Thermal Shock (0 to 100~C in water baths, 2 minutes per bath), 15 cycles:
Five packages.
RGA has also been carried out on similar packages after sealing and after 15 cycles of 0 to 100~C thermal shock in water baths. The measured water content was under the 5000 ppm limit specified by MIL-STD-883 for hermetic packages. These results clearly show that the process described above simultaneously forms robust hermetic seals around the optical fibres and between the package and the lid.
1~ Optical transmission and return loss measurements have been carried out at 1.53 ~Lm on fibre feedthroughs made with the above process. The loss per feedthrough was less than 0.05 dB. No return peaks above -70 dB
were observed in CDR scans. The fibre sealing process described above, therefore, does not result in any cracking or microbending of the fibres.
CA 022~9971 1998-12-30
Claims (7)
1. A method for making a hermetically sealed package, which package comprises a housing, a lid, and a feedthrough for at least one stripped optical fibre, characterised in that the method comprises the following steps:
~ placing the optical fibre or fibres and at least one solder preform between the sealing surface of the lid and the sealing surface of the housing ~ sealing the assembly by applying pressure and heat so as to press the fibre or fibres into the solder.
~ placing the optical fibre or fibres and at least one solder preform between the sealing surface of the lid and the sealing surface of the housing ~ sealing the assembly by applying pressure and heat so as to press the fibre or fibres into the solder.
2. A method according to claim 1, characterised in that the optical fibre or fibres are solder coated prior to sealing the package.
3. A method according to claim 1 or 2, characterised in that after sealing of the package, additional heat is applied to melt the solder.
4. A method according to any one of claims 1-3, characterised in that the package body is provided with a sealing ring which forms the sealing surface of the package body.
5. A method according to any one of claims 1-4, characterised in that prior to the sealing step a solder preform is placed on top of the fibre or fibres and that a further layer comprising at least one fibre is placed on top of the solder ring.
6. A method according to any one of claims 1-5, characterised in that the (total) thickness of the preform or preforms exceeds the diameter of the stripped fibre multiplied by the number of fibre layers.
7. A hermetically sealed package obtainable by the method according to any one of claims 1-6, which package comprises a housing and a lid sealed onto it by means of a continuous solder seam, through which solder seam at least one fibre is fed.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US2120196P | 1996-07-03 | 1996-07-03 | |
| US60/021,201 | 1996-07-03 | ||
| EP96202047.5 | 1996-07-19 | ||
| EP96202047 | 1996-07-19 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2259971A1 true CA2259971A1 (en) | 1998-01-15 |
Family
ID=56289777
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002259971A Abandoned CA2259971A1 (en) | 1996-07-03 | 1997-07-01 | Method for making a hermetically sealed package comprising at least one optical fibre feedthrough |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP0909400A1 (en) |
| JP (1) | JP2001508184A (en) |
| AU (1) | AU3442297A (en) |
| CA (1) | CA2259971A1 (en) |
| WO (1) | WO1998001783A1 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB0110366D0 (en) | 2001-04-27 | 2001-06-20 | Tyco Electronics Raychem Nv | Optical fibre sealing |
| US7113686B2 (en) * | 2002-04-12 | 2006-09-26 | Tyco Electronics Raychem Nv | Optical circuit enclosure |
| DE102020114952B4 (en) | 2020-06-05 | 2024-07-18 | Schott Ag | Hermetically sealed optoelectronic module with increased coupling of electromagnetic radiation |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5433683A (en) * | 1977-07-08 | 1979-03-12 | Hitachi Ltd | Air seal mounting for light emitting element |
| US4788406A (en) * | 1987-01-23 | 1988-11-29 | Battelle Memorial Institute | Microattachment of optical fibers |
| US5061035A (en) * | 1990-09-27 | 1991-10-29 | Hughes Aircraft Company | Hermetically sealed optical fiber arrays and method for forming same |
| US5412748A (en) * | 1992-12-04 | 1995-05-02 | Kabushiki Kaisha Toshiba | Optical semiconductor module |
| CA2135758A1 (en) * | 1993-03-31 | 1994-10-01 | Toshiaki Kakii | Optical fiber array |
-
1997
- 1997-07-01 JP JP50475598A patent/JP2001508184A/en active Pending
- 1997-07-01 CA CA002259971A patent/CA2259971A1/en not_active Abandoned
- 1997-07-01 WO PCT/EP1997/003492 patent/WO1998001783A1/en not_active Application Discontinuation
- 1997-07-01 EP EP97930492A patent/EP0909400A1/en not_active Withdrawn
- 1997-07-01 AU AU34422/97A patent/AU3442297A/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| WO1998001783A1 (en) | 1998-01-15 |
| AU3442297A (en) | 1998-02-02 |
| JP2001508184A (en) | 2001-06-19 |
| EP0909400A1 (en) | 1999-04-21 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Dead |