United States Patent [19]
`Kunikane et al.
`
`[11] Patent Number:
`[45] Date of Patent:
`
`5,048,912
`Sep. 17, 1991
`
`[54] OPTICAL FIBER SWITCHING WITH
`SPHERICAL LENS AND METHOD OF
`MAKING SAME
`[75] Inventor: I Tatsuro Kunikane, Yokohama;
`Kiyoshi Terai, Taito; Hidek; Isono,
`Yokohama, all of Japan; Michihiro
`Takamatsu, Tokorozawa, Japan
`[73] Assignee: Fujitsu Limited, Kawasaki, Japan
`[21] Appl. No.:
`439,025
`[22] PCT Filed:
`Mar. 9, 1989
`[86] PCT No.:
`PCI/JP89/00253
`§ 371 Date:
`Nov. 9, 1989
`§ 102(e) Date:
`Nov. 9, 1989
`[87] PCT Pub. No.: WO89/08858
`PCT Pub. Date: Sep. 21, 1989
`Foreign Application Priority Data
`[30]
`Mar. 9, 1988 [JP]
`Japan ................................ .. 63-55326
`
`
`
`Apr. 15, 1988 [JP] Jul. 27, 1988 [JP]
`
`
`
`Japan Japan .............................. .. 63185536
`
`[51] Int. Cl.5 ....................... .. GOZB 6/32; C03C 27/02
`[52] US. Cl. ....................................... .. 385/23; 65/4.2;
`65/594; 385/35
`[58] Field of Search ............. .. 350/96.10, 96.15, 96.17,
`350/96.18, 96.20, 96.21, 320, 252, 253; 65/594,
`I
`,
`4.2, 37
`
`[56]
`
`References Cited
`U.S. PATENT DOCUMENTS
`
`4,239,331 12/1980 Aoyama ......................... .. 350/96.20
`4,307,935 12/1981 Monnier
`..... .. 1150/9620
`
`4,702,547 10/1987 Enochs . . . . , .
`
`. . . . . .. 350/9620
`
`4,875,750 10/1989 Spaeth et a1. . . . . . .
`4,966,439 10/1990 Althaus et a1.
`
`. . . . .. 350/9618
`.... .. 350/253
`
`4,988,375 1/1991 Bornhauser . . . . . i . .
`
`. . . . . .1 65/594
`
`350/9618
`4,989,940 2/1991 Wollenweber
`4,997,252 3/1991 Sugawara et al. ............. .. 350/9620
`
`FOREIGN PATENT DOCUMENTS
`
`56-117715 ofOOOO Japan ......................... .. 350/96.21 X
`54-66150 5/1979 Japan ......................... .. 350/9618 X
`62-201706 12/1987 Japan ......................... .. 1450/9617 X
`62-293210 12/1987 Japan ......................... .. 350/96.l8 X
`Primary Examiner-Brian Healy
`Attorney, Agent, or Firm—Staas & Halsey
`[57]
`ABSTRACT
`A ferrule having an optical ?ber connected thereto and
`a spherical lens are ?xed in a cylindrical lens holder to
`form a ?ber collimator. The thickness of a cylindrical
`wall of the lens holder is made smaller at a spherical lens
`receiving portion than the other portion and the cylin
`drical lens holder is ?xed to a substrate by welding. A
`pair of such ?ber collimators are provided in an oppos
`ing relationship to each other on the substrate, and an
`optical function element is disposed between the oppos
`ing ?ber collimators to form an optical device. By pro- .
`vision of a light path changing over mechanism as such
`optical function element, an optical switch of a small
`size having a high performance can be provided.
`
`4,237,474 12/1980 Ladany ........................... .. 350/96.20
`
`9 Claims, 4 Drawing Sheets
`
`21
`
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`
`
`
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`
`Petitioner Ciena Corp. et al.
`Exhibit 1042-1
`
`

`

`US. Patent
`
`Sep. 17, 1991
`
`Sheet 1 of4
`
`5,048,912 V
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`Petitioner Ciena Corp. et 21].
`Exhibit 1042-2
`
`Petitioner Ciena Corp. et al.
`Exhibit 1042-2
`
`

`

`US. Patent
`
`Sep. 17, 1991
`
`sheet 2 of 4
`
`5,048,912
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`Exhibit 1042-3
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`Petitioner Ciena Corp. et al.
`Exhibit 1042-3
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`

`

`US. Patent
`
`Sep. 17, 1991‘
`
`Sheet 3 of 4
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`5,048,912
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`Petitioner Ciena Corp. et 21].
`Exhibit 1042-4
`
`Petitioner Ciena Corp. et al.
`Exhibit 1042-4
`
`

`

`US. Patent
`
`Sep. 17, 1991
`
`Sheet 4 of 4
`
`5,048,912
`
`
`
`
`
`
`
`Petitioner Ciena Corp. et 21].
`Exhibit 1042-5
`
`Petitioner Ciena Corp. et al.
`Exhibit 1042-5
`
`

`

`OPTICAL FIBER SWITCHING WITH SPHERICAL
`LENS AND METHOD OF MAKING SAlNiE
`
`BACKGROUND OF THE INVENTION
`1. Field of the Invention
`This invention relates to an optical device which
`employs an optical part wherein a spherical lens is force
`?tted in a cylindrical lens holder, and more particularly
`to an optical switch which includes an optical part of
`the type mentioned.
`2. Description of the Related Art
`In the ?eld of optical communications or optical
`transmissions, a spherical lens is widely applied in order
`to convert light emitted from a light emitting device or
`an emergent end of an optical ?ber into a parallel beam
`of light or reversely to focus a parallel beam of light to
`a light detecting device or an incident end of an optical
`?ber. In such applications of a spherical lens, a structure
`is demanded which can ?xedly hold a spherical lens
`?rmly therein because the relative positional relation
`ship between a spherical lens and either a light emitting
`device, a light detecting device, an optical ?ber has a
`direct in?uence on the optical coupling ef?ciency of an
`optical device.
`Conventionally, in ?xing a spherical lens which has a
`spherical outer pro?le and is not necessarily easy to
`handle, the spherical lens is, for example, force ?tted
`into a cylindrical lens holder so as to hold the spherical
`lens in the lens holder, and the spherical lens is ?xed
`together with the cylindrical lens holder to a substrate
`by laser welding or the like. To better hold the spherical
`lens in the lens holder, the diameter of the spherical lens
`is set a little greater than the diameter of a receiving
`hole formed in the lens holder. Accordingly, the spheri
`cal lens can be held at a predetermined position in the
`lens holder by pushing the spherical lens into the receiv
`ing hole with a suitable force. Such holding structure of
`the spherical lens by force ?tting assures ?rm holding of
`the spherical lens making good use of plastic deforma
`tion and/or elastic deformation of the lens holder. How
`ever, the holding structure has the following draw
`backs.
`In particular, where the material of the lens holder is
`a soft metal material such as invar, covar or brass, the
`lens holder undergoes plastic deformation by force
`?tting of the spherical lens. The lens holder swells at the
`force ?t portion thereof so that the outer pro?le of the
`lens holder is nonuniform. Accordingly, it is a problem
`that, when the lens holder is closely contacted with and
`?xed to a flat substrate, then the center axis of the lens
`holder will not provide a parallel relationship to the flat
`surface of the substrate. On the other hand, where a
`hard metal material such as stainless steel is used as a
`material of the lens holder in order to omit corrosion
`preventing processing which is required for such a soft
`metal material as described above or in order to permit
`?xation of the lens holder to the substrate by welding,
`there is another problem, in addition to the problem
`described above, that the spherical lens is likely to be
`broken. In order to eliminate this, the accuracy in di
`mension of the diameter of the spherical lens and the
`diameter of the receiving hole of the lens holder must
`necessarily be raised specially, which makes a problem
`that the production cost is raised considerably.
`An optical part wherein a spherical lens is force ?tted
`into a cylindrical lens holder from an end of the lens
`holder and a ferrule to which an optical ?ber is con
`
`25
`
`45
`
`60
`
`65
`
`1
`
`5,048,912
`
`2
`nected is ?tted in and ?xed to the other end of the lens
`holder is often used as an optical part which employs a
`spherical lens. Such optical part will be hereinafter
`referred to as a ?ber collimator. Such a ?ber collimator
`is frequently used, for example, in an optical switch for
`changing over a light path. Optical switches are widely
`used as a basic optical device, and optical devices are
`demanded which are high in reliability and suitable in
`miniaturization.
`Conventionally, various types of optical switches for
`changing over an optical path have been proposed in
`cluding a type wherein a movable prism is selectively
`inserted into a light path and another type wherein the
`coupling coef?cient of a directional coupling device is
`changed depending upon an electro-optical effect.
`Among optical switches of the types mentioned, a con
`ventional mechanical optical switch wherein a movable
`prism is selectively inserted into a light path has a draw
`back that the entire switch mechanism inevitably has a
`large overall size and another drawback that the prob
`lem of incomplete switching cannot be avoided which
`may be caused by particles produced by abrasion of a
`sliding portion of the switch or by dust or the like ad
`mitted into the switch. Particularly the problem of in
`complete switching caused by dust is signi?cant where
`the switching interval is very long.
`
`SUMMARY OF THE INVENTION
`Accordingly, it is an object of the present invention
`to provide an optical device employing a ?ber collima
`tor which overcomes such drawbacks of the prior art
`described above and wherein, when a lens holder is to
`be closely contacted with and ?xed to a flat substrate,
`the optical axis thereof can be readily made parallel to
`the surface of the substrate.
`'
`It is another object of the present invention to pro
`vide an optical switch which is simple in construction,
`high in reliability and suitable for miniaturization.
`According to one aspect of the present invention,
`there is provided an optical device wherein at least two
`?ber collimators each including a spherical lens, a cylin
`drical lens holder having a smaller inner diameter than
`the diameter of the spherical lens and having the spheri
`cal lens ?xed therein by force ?tting, and a ferrule in
`serted in and ?xed to the lens holder and having an
`optical ?ber connected thereto, are ?xed on a substrate
`in a predetermined spaced relationship from each other.
`An optical function means is interposed between the
`?ber collimators. Each ?ber collimator is characterized
`in that the thickness of a cylindrical wall of the cylindri
`cal lens holder is made smaller along a force ?tting
`route of the spherical lens and a peripheral portion
`around the force ?tting route than at the other portion,
`and that the cylindrical lens holder'is ?xed to the sub
`strate by welding.
`With the optical device, since deformation of the lens
`holder upon force ?tting does not have an influence on
`the ?xed portion of the lens holder to the substrate,
`accurate positioning of the lens holder is realized. Fur
`ther, even where the lens holder is formed from a hard
`material, possible damage upon force ?tting of the
`spherical lens can be prevented without raising the
`accuracy in. dimension of the spherical lens and a receiv
`ing hole-for the spherical lens.
`The optical function‘ means provided between the
`?ber collimators may include an optical switch, an opti
`
`Petitioner Ciena Corp. et al.
`Exhibit 1042-6
`
`

`

`5,048,912
`4
`FIG. 7 is a sectional view taken along line VII-VII
`of FIG. 6;
`FIG. 8 is a detailed sectional view of a ?ber collima
`tor of FIG. 6; and
`FIG. 9 is a sectional view showing another embodi
`ment of a soldered portion.
`
`5
`
`20
`
`30
`
`35
`
`3
`cal attenuator, a light combining and/or separating _
`device or the like.
`According to another aspect of the present invention,
`there is provided an optical switch which employs a
`plurality of ?ber collimators and an optical function
`means which is a means for changing over a path of
`light by inserting a movable prism selectively into the
`path of light.
`The light path changing over means may include a
`casing, an iron core, a coil wound around the iron core
`and accommodated in the casing, a ?xed member pro
`vided on the outside of the coil, a substantially L-shaped
`movable member having a bent portion for contacting
`with an end portion of the ?xed member, a prism pro
`vided on the movable member for changing over the
`path of light, and urging means for urging the movable
`member toward the ?xed member. Further, the ?rst
`?ber collimator and the second ?ber collimator may be
`provided in an opposing relationship on the opposite
`sides of the light path changing over means such that
`optical axes thereof may coincide with each other, and
`the third ?ber collimator may be provided on the sub
`strate on the side of the second ?ber collimator such
`that light which is emitted from the ?rst ?ber collimator
`and the path of which is displaced in a parallel relation
`ship to the incident light by the prism may be intro
`duced into the third ?ber collimator.
`With the optical switch having such a construction as
`described above, when the coil is not excited, the prism
`is inserted in the path of light so that light from the ?rst
`?ber collimator is introduced into the third ?ber colli
`mator. When the coil is excited, the movable member is
`pivoted to displace the prism out of the path of light so
`that light from the ?rst ?ber collimator may be intro
`duced into the second ?ber collimator.
`According to a further aspect of the present inven
`tion, there is provided an encapsulating structure for an
`optical device wherein the optical device which em
`ploys the ?ber collimators is enclosed in a housing made
`of a metal material. The encapsulating structure for an
`optical device is constituted such that a jacket of an
`optical ?ber is partly removed at an end portion thereof
`and a metal coating is formed continuously from a sur
`face of the optical ?ber from which the jacket is re
`moved to a surface of an intermediate portion of the
`jacketed ?ber. The optical ?ber on which the metal
`coating is formed extends through a hole formed in an
`enclosing housing made of a metal material and the
`metal coating is soldered to the metal housing at the
`hole.
`
`DESCRIPTION OF THE PREFERRED
`EMBODIMENTS
`In the following, a present invention will be de
`scribed in detail in connection with the embodiments
`thereof shown in the drawings.
`FIGS. 1 and 2 show a sectional view and a plan view
`of an embodiment wherein the present invention is ap
`plied to an optical switch. The optical switch shown
`includes a housing 1 formed by molding of a plastic
`material and composed of an upper housing 1a and a
`lower housing 1b. A substrate 3 formed, for example,
`from stainless steel is accommodated in the housing 1.
`The substrate 3 has a ?rst recess 5 formed at a central
`portion of a front surface side thereof while a second
`recess 7 and a third recess 9 are formed on a reverse
`surface side of the substrate 3. An input side ?ber colli
`mator 11 and a pair of output side ?ber collimators 13
`and 15 are provided on the substrate 3 as shown in FIG.
`2. The ?ber collimator 11 and the ?ber collimator 13 are
`disposed in an opposing relationship such that optical
`axes thereof may coincide or be aligned with each
`other. Since the ?ber collimators 11, 13 and 15 have the
`same construction, only the construction of the ?ber
`collimator 11 will be described as a representative in the
`following.
`The ?ber collimator 11 includes a generally cylindri
`cal lens holder 17 having a small diameter portion 170
`and a large diameter portion 1711, a spherical lens 19
`force ?tted in the lens holder 17 from the small diameter
`170 side, and a ferrule 23 ?xedly inserted in the lens
`holder 17 from the large diameter side 17b and having
`an optical ?ber 21 ?xedly inserted therein. The lens
`holder 17 and the ferrule 23 are formed, for example,
`from stainless steel. In force ?tting the spherical lens 19
`for ?xation, since the small diameter portion 17a is
`formed on the lens holder 17, the small diameter portion
`17a is deformed comparatively readily. Consequently
`the spherical lens 19 is prevented from being broken by
`a reactive force to such force ?tting. Further, even if
`the small diameter portion 17a of the lens holder 17 is
`_ deformed, such deformation will not have an in?uence
`on the large diameter portion 17b of the lens holder 17.
`Accordingly, when the ?ber collimator 11 is ?xed to
`the substrate 3, the optical axis of the ?ber collimator 11
`can be maintained in parallel to the ?at surface of the
`substrate 3 with certainty.
`The ?ber collimators 11, 13 and 15 are ?xed to the
`surface of the substrate 3 in the following manner. In
`particular, the ?ber collimators 11, 13 and 15 are posi
`tioned on the substrate 3 using a positioning jig having
`three V-shaped grooves formed thereon for positioning‘
`the ?ber collimators 11, 13 and 15, and then the lens
`holders 17 of the ?ber collimators 11, 13 and 15 are
`?xed to the substrate 3 by laser welding through small
`holes 25 formed in bottom walls ofthe second and third
`recesses 7 and 9 of the substrate 3. Since the small diam
`eter portions 17a are formed on the lens holders 17 as
`described above, the ?ber collimators 11, 13 and 15 can
`be ?xed by welding such that the optical axes thereof
`may maintain a parallel relationship to the flat surface of
`the substrate 3 with certainty.
`
`45
`
`50
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`FIG. 1 is a sectional view of an embodiment wherein
`the present invention is applied to an optical switch;
`FIG. 2 is a plan view of the optical switch of FIG. 1;
`FIG. 3 is a vertical sectional view of a light path
`changing over mechanism;
`FIGS. 4A and 4B are schematic views illustrating
`operation of the light path changing over mechanism of
`- FIG. 3, and wherein FIG. 4A shows the mechanism
`when a coil is not excited and FIG. 4B shows the mech
`anism when the coil is excited;
`FIG. 5 is a sectional view showing another embodi
`ment of a ?ber collimator;
`'
`FIG. 6 is a sectional view of an embodiment showing
`an encapsulating structure for an optical device accord-_
`ing to the present invention;
`
`65
`
`Petitioner Ciena Corp. et al.
`Exhibit 1042-7
`
`

`

`20
`
`25
`
`5
`In each of the ?ber collimators 11, 13 and 15 de
`scribed above, in order to reduce the thickness of a
`portion of the lens holder 17 which corresponds to a
`route along which a spherical lens 19 is to be force ?tted
`and a peripheral portion around the route, the lens
`holder is machined from the outer side to the inner side
`of the lens holder 17 to form the small diameter portion
`170. Such a manner of formation is employed from the
`following two reasons. In particular, ?rstly a machining
`operation from the outer side to the inner side of the
`lens holder 17 made of a metal material is generally
`easy. Secondly, if the thickness of the portion of the lens
`holder into which the spherical lens 19 is force ?tted is
`small, deformation of the lens holder upon force ?tting
`of the spherical lens _will reach an outer peripheral por
`tion of the lens holder, and hence, if the small diameter
`portion 170 is not formed on the lens holder 17, then
`when the lens holder 17 is closely contacted with and
`?xed to the substrate 3 having a flat surface, the optical
`axis thereof cannot be put into a parallel condition to
`the ?at surface of the substrate 3.
`A light path changing over mechanism 27 is inter
`posed between the input side ?ber collimator 11 and the
`output side ?ber collimators l3 and 15 for changing
`over a path of light emitted from the input side ?ber
`collimator 11. The light path changing over mechanism
`27 is constructed in the following manner. As best
`shown in FIG. 3, a coil 33 wound around a bobbin 31 is
`?tted on and attached to an iron core 29 to form a unit,
`and the unit is accommodated in a casing 35 made of a
`plastic material. A ?xed plate member 37 formed, for
`example, from a soft magnetic material is disposed on
`the outside of the coil 33. A diamond-shaped prism 41 is
`mounted on a surface of a longer leg portion 390 of a
`movable plate member 39 of a substantially L-shaped
`con?guration formed, for example, from a soft magnetic
`material. A shorter leg portion 39b of the movable plate
`member 39 extends to a position corresponding to the
`iron core 29, and an end portion 370 of the ?xed plate I
`member 37. The ?xed plate member 37 is held in abut
`40
`ting engagement with an obtusely bent portion 390 of
`the movable plate member 39. The movable plate mem
`ber 39 is normally urged to pivot around the abutting
`end portion 370 of the ?xed plate member 37 toward the
`?xed plate member 37 by a leaf spring 43 force ?tted in
`45
`a leaf spring receiving portion 35a of the casing 35. As
`shown in FIG. 2, the movable plate member 39 has a
`projection 45 formed thereon while the ?xed plate
`member 37 has a stopper 47 formed thereon for engag
`ing with the projection 45.
`'
`The light path changing over mechanism 27 having
`such a construction as described above is adhered to a
`wall face of the ?rst recess 5 of the substrate 3 in the
`following manner. In particular, the light path changing
`over mechanism 27 is ?xed to the substrate 3 by means
`of a pair of ultraviolet light curable resin layers 51 with
`a transparent plate member 49 disposed between the
`casing 35 of the light path changing over mechanism 27
`and the wall face of the ?rst recess 5 of the substrate 3.
`When ultraviolet light is irradiated toward the inside of
`the transparent plate member 49, it is reflected from a
`pair of interfaces between the transparent plate member
`49 and the ultraviolet light curable resin layers 51 or the
`other interfaces between the ultraviolet light curable
`resin layers 51 and the wall face of the substrate 3 as
`well as the case 35 and thus spreads over the entire
`transparent plate member 49. Consequently, the ultravi
`olet light curable resin is caused to cure rapidly by the
`
`5,048,912
`6
`irradiation of the ultraviolet light. Since adhesion by the
`ultraviolet light curable' resin can be carried out at a low
`temperature, such possible problems that an optical part
`may be deformed by ?xation using an adhesive or that a
`stress may act upon an optical part can be avoided.
`Subsequently, operation of the optical switch de
`scribed above will be described.
`FIG. 4A shows the optical switch in a condition
`wherein the coil 33 is not excited. In this condition, the
`movable plate member 39 is pressed against the ?xed
`plate member 37 by the leaf spring 43 to insert the dia
`mond-shaped prism 41 in a path of light. Thus, light
`emitted from the incident side ?ber collimator 11 is
`totally reflected twice by the diamond-shaped prism 41
`inserted in the light path to bend the path thereof so that
`it is introduced into the output side ?ber collimator 15.
`To the contrary,' if the coil 33 is energized to excite the
`iron core 29, the shorter leg portion 39b of the movable ~
`plate member 39 is attracted to the iron core 29. The
`attraction causes the movable plate member 39 to pivot
`in the counterclockwise direction in FIG. 3 around the
`abutting end portion 37a of the ?xed plate member 37
`against the urging force of the leaf spring 43. The dia
`mond-shaped prism 41 resultantly moves out of the
`light path as shown in FIG. 4B. Consequently, light
`emitted from the input side ?ber collimator 11 advances
`straightforwards and thus enters the output side ?ber
`collimator 13. In this manner, in the optical switch of
`the present embodiment, the path of light emitted from
`the input side ?ber collimator 11 can be changed over
`between the output side ?ber collimators 13 and 15.
`_Since the movable plate member 39 is pivoted, upon
`energization of the coil 33, in the counterclockwise
`direction until the projection 45 of the movable plate
`member 39 is contacted with the stopper 47, a stabilized
`change-over characteristic can be obtained.
`The optical switch of the embodiment described
`above has a reduced susceptibility to influence of dust
`or the like from the outside because the L—shaped mov
`able plate member 39 is pivoted in a line contacting
`relationship around the abutting end portion 370 of the
`?xed plate member 37 disposed on the outside of the
`coil 33 comparing with an optical switch of a conven
`tional type wherein a prism for changing over a light
`path is moved under the guidance of a slider and a slider
`guide. Further, since the movable plate member is piv
`oted in a line contacting relationship with the ?xed plate
`member, abrasion at such pivoting portions can be al
`most ignored. Further, since the coil 33, iron core 29
`and movable plate member 39 are arranged in a good
`arrangement from the point of view of a magnetic ef?
`ciency as shown in FIGS. 3, 4A and 4B, miniaturization
`of the optical switch is possible.
`While the embodiment described above concerns
`with an optical switch, the present invention is not
`limited to such optical switch, and some other optical
`function part or optical function mechanism such as, for
`example, an optical attenuator, a light combining
`/separating device or an optical coupler may be inter
`posed between the input side ?ber collimator 11 and the
`output side ?ber collimators 13 and 15.
`FIG. 5 shows a sectional view of another embodi
`ment of the ?ber collimator of the present invention. In
`the present embodiment, a small diameter portion 530 of
`a lens holder 53 to which a spherical lens 19 is ?xed by
`force ?tting is formed at a substantially central portion
`of the lens holder 53 in a longitudinal direction (in the
`direction of an optical axis). A pair of large diameter
`
`65
`
`Petitioner Ciena Corp. et al.
`Exhibit 1042-8
`
`

`

`5
`
`25
`
`30
`
`35
`
`7
`portions 53b and 53c are formed on the opposite sides of r
`the small diameter portion 530. The inner diameter of
`the large diameter portion 53b of the lens holder 53 into
`which a ferrule 23 is inserted and ?xed is the same as the
`inner diameter of the small diameter portion 530 while
`the inner diameter of the large diameter portion 530 is
`set greater than the inner diameter of the smaller diame
`ter portion 530. The reason why the inner diameter of
`the large diameter portion 53c is made greater is that it
`is intended to eliminate frictional resistance at the large
`diameter portion 53c when the spherical lens 19 is force
`?tted into the small diameter portion 530. According to
`the structure of the present embodiment, the spherical
`lens 19 can be supported on the opposite sides thereof
`on a substrate, and accordingly the strength in ?xation
`is increased. Further, since the inside of the large diame
`ter portion 530 is hollow, it is possible to carry, at the
`hollow location an optical element not shown such as a
`glass block with a ?lter ?lm.
`Referring now to FIG. 6, there is shown a sectional
`view of an optical device of the present invention which
`is enclosed in an encapsulating structure. In recent
`years, as the range of applications of optical communi
`cation systems or optical transmission systems which
`employ an optical ?ber as a transmission path is ex
`panded, optical devices are put into use in various envi
`ronmental conditions. Accordingly, an encapsulating
`structure for an optical device wherein no bad influence
`is had on the performance thereof in a high temperature
`and/ or high humidity condition or in a low temperature
`condition is demanded. The embodiment of FIG. 6
`provides a perfect encapsulating structure for an optical
`device of the present invention.
`Referring to FIG. 6, a pair of holes 57 are perforated
`in the opposite end walls of an encapsulating structure
`55 made of a solderable metal material. An optical ?ber
`61 having a metal ?lm 59 formed thereon extends
`through each of the holes 57. The inside of the metal
`encapsulating structure 55 is enclosed by ?xing the
`metal ?lms 59 to the metal encapsulating structure 55 at
`the holes 57 by soldering. Upon soldering, it is prefera
`ble to use solder of a low melting point such as 110° to
`120° C. or so in order to prevent deterioration of a
`coating (jacket) of an optical ?ber. A terminal end of
`each of the optical ?bers 61 in the inside of the metal
`45
`encapsulating structure 55 is connected to a ?ber collié
`mator 63 which has substantially the same construction
`as the ?ber collimator 11 described hereinabove. Also
`contained within the encapsulating structure 55, an
`optical function element 65 such as a light path chang
`ing over mechanism is interposed between the opposing
`ends of the ?ber collimators 63 so as to exhibit a desired
`function. The ?ber collimators 63 and the optical func
`tion element 65 are ?xed to a substrate 60 made of a
`metal material. It is to be noted that the inside of the
`metal encapsulating structure 55 may be ?lled with inert
`gas such as N; to prevent a possible inter-molecular leak
`or the like.
`Referring now to FIG. 7, there is shown a sectional
`- view taken along line VII—VII of FIG. 6. Each of the
`optical ?bers 61 is composed of a bare optical ?ber
`composed of a core 63 and a clad 65. An inner jacket 69
`made of a silicone resin or the like is formed on the bare
`optical ?ber 67, and an outer jacket 71 made of nylon or
`the like formed on the inner jacket 69. The coating 59 of 65
`a metal such as, for example, nickel is formed on the
`surface of the optical ?ber 61 by such means as electro
`less plating or metallizing processing. According to
`
`5,048,912
`8
`such optical ?ber structure, since the inner jacket 69 and
`the outer jacket 71 act as buffer layers, even ifa tensile
`force acts upon the optical ?ber in FIG. 6, the possibil
`ity of damage to the optical ?ber is low compared to an
`optical ?ber of a conventional structure.
`FIG. 8 is a sectional view of the ?ber collimator 63
`shown in FIG. 6. The ?ber collimator 63 is constituted
`such that the bare optical ?ber 67 is inserted in and ?xed
`to a ferrule 73. The ferrule 73 which is inserted in and
`?xed to a cylindrical lens holder 17 to which a spherical
`lens 19 is ?xed by force ?tting. The lens holder 17 has a
`small diameter portion 170 and a large diameter portion
`17b. The spherical lens 19 is force ?tted in and ?xed to
`a receiving hole of the small diameter portion 17a of the
`lens holder 17. The metal coating 59 provided on the
`surface of the outer jacket 71 of the optical ?ber 61
`extends to a portion of the bare optical ?ber 67 which is
`an exposed portion of the optical ?ber. Consequently,
`possible transmission of air from and to the outside by
`way of a gap between the bare optical ?ber 67 and the
`inner jacket 69 or another gap between the inner jacket
`69 and the outer jacket 71 is prevented, thereby attain
`ing a good enclosed condition. A bonding agent 75 is
`?lled in the inside of the ferrule 73.
`With the encapsulating structure of the present em
`bodiment described above, since the optical ?ber 61 is
`?xed by soldering to the encapsulating structure 55 by
`way of the metal coating 59 formed on the outer jacket
`71, the optical ?ber can be bent by a greater amount
`than is possible with a conventional encapsulating struc
`ture. As a result, handling of the device during manu
`facture is facilitated so that an optical device of a re-'
`duced size can be provided.
`It is to be noted that, as shown in FIG. 9, for solder
`ing of the metal coating 59, a solder receiver 81 may be
`formed at an outer end portion of a hole 79 which is
`formed in the encapsulating structure. The hole 79 has
`an inner diameter substantially coincident to the outer
`pro?le of the metal coating 59 of the optical ?ber 61.
`According to the structure, the amount of solder to be
`used for soldering can be reduced compared to that of
`the preceding embodiment, and soldering can be carried
`out readily.
`Since the thickness of a portion of a lens holder in
`which a spherical lens is to be force ?tted is made
`smaller than that of the other portion of the lens holder,
`deformation of the lens holder caused by force ?tting
`does not have an in?uence on another portion of the
`lens holder at which the lens holder is ?xed to a sub
`strate. Consequently, accurate positioning of the lens
`holder can be attained readily. According to a preferred
`embodiment, an optical switch can be provided which
`is reduced in influence of abrasion of a movable portion
`and dust or the like from the outside and is suitable for
`‘miniaturization and high in reliability. According to an
`optical device which employs an enclosing structure of
`the present invention, handling of an optical ?ber in the
`inside of a housing is facilitated and the performance of‘
`the optical device can be exhibited suf?ciently in a
`severe environmental condition such as a high tempera
`ture and/or high humidity condition or a low tempera
`ture condition.
`We claim:
`1. An optical device for providing an optical function
`for a plurality of optical ?bers, comprising:
`a substrate;
`at least two