KR20080090324A - Constructure for protecting optical fiber end surface - Google Patents

Abstract

A protection structure for an optical fiber end surface is provided to enable a user to easily implement or remove a transparent optical member by coupling an exit face of the optical fiber with an incident face of the transparent optical member using a protective member. Plural optical fibers(2) emit an incident beam through exit faces thereof. A transparent optical member(3) has a refractive index similar to that of a core material of the optical fiber. The emitted beam from the exit face of the optical fiber is incident on an incident face of the transparent optical member. A protective member(10) is applied between the exit face(21) of the optical fiber and the incident face(31) of the transparent optical member. The protective member prevents the exit face from being attached to the incident face. The incident face of the transparent optical member is greater than the exit face of the optical fiber. The optical fiber and the transparent optical member are detachably attached to each other through the protective member.

Description

Optical fiber end face protection structure {CONSTRUCTURE FOR PROTECTING OPTICAL FIBER END SURFACE}

The present invention relates to a protective structure of the light exit end of the optical fiber.

Optical fibers widely used as optical transmission media are susceptible to lowering of transmission loss due to adhesion of dust and contaminants to the output end surface of the optical fiber at the time of transmission of high power light, and to end surface damage due to seizure of deposits. There is a problem of lowering the beam quality. In particular, when transmitting short wavelength light or the like having a high energy density of 450 nm or less, the exit end surface is likely to be contaminated.

Further, when the light is guided to the optical fiber, a part of the waveguide light is reflected on the light exit end surface, so that a so-called return light retrogrades into the optical fiber. Since the return light is high in proportion to the power of the incident light, when high-incidence incident light is used, the optical fiber itself and the connected optical device may be adversely affected even if the anti-reflection special treatment is performed on the light exit end surface. Known.

In particular, in the case of a fiber bundle or the like, which collectively emits light from a plurality of light sources using a plurality of optical fibers, the power of the plurality of light sources is collected at the light exit end surface and is emitted. The adhesion speed of the contaminants and the return optical power are higher. In addition, in the fiber bundle, it is preferable to reduce the amount of return light as much as possible because the return light may affect and damage the adhesive or the like used to bundle the fibers.

Patent Literature 1 discloses an optical fiber end face structure in which coreless fibers are fusion-spliced to an exit end face of an optical fiber and a coating material having a refractive index higher than that of the coreless fiber is provided around the coreless fiber. . In Patent Document 1, the end face damage can be prevented by the coreless fiber, and by controlling the length of the coreless fiber, the return light is effectively returned from the coating material portion having a refractive index higher than that of the coreless fiber around the coreless fiber. It is described to prevent the retrograde of the return light in the optical fiber by emitting.

Further, Patent Document 2 discloses an optical fiber in an optical fiber terminal in which one end surface of a coreless fiber made of a material having a material having substantially the same and uniform refractive index as the core is bonded to an end surface of an optical fiber having a core clad structure. An optical fiber terminal is disclosed in which an optical path length of a coreless fiber is set such that light incident on the coreless fiber from the beam is emitted at a beam diameter within the outer diameter of the exit end of the coreless fiber. By such a configuration, it is described that the light emitted from the optical fiber can be broadened and emitted, and the amount of returned light can be reduced by increasing the reflection loss.

[Patent Document 1] Japanese Unexamined Patent Publication No. 2005-303166

[Patent Document 2] International Publication No. 2004/053547 Pamphlet

The optical fiber end surface structure of patent document 1 and the optical fiber terminal of patent document 2 are all bonded to the end surface protection member (coreless fiber) attached to the output end of an optical fiber by fusion | melting etc. When the optical fiber and the end surface protection member are adhered by fusion, the respective aperture difference is limited. When the difference in aperture between the optical fiber to be fused and the end face protection member is large, the difference in softening speed is large because the difference in heat capacity of both is large, and as a result, the dopant in the core of the optical fiber having a thin diameter during softening of the end face protection member is clad. It spreads to wealth. When the dopant is diffused into the cladding portion, the optical fiber has a weak light concentrating effect, thereby increasing radiation loss, and deterioration in transmission characteristics of the optical fiber itself. Therefore, in the case of gluing by fusion, the aperture difference between the optical fiber and the end surface protection member is limited, and it is difficult to fusion the end surface protection member having two or more apertures.

In order to collectively protect the end surfaces of the plurality of optical fibers or the end surfaces of the fiber bundles, the end surfaces of the optical fibers are fused with an end surface protection member that is twice as large as the diameter of one optical fiber. Therefore, it is difficult to set it as the structure which adhere | attached the end surface protection member by fusion | fusing, and neither patent document 1 nor patent document 2 has the description which targets the end surface of several optical fiber.

In addition, even if the optical fiber output end is protected against the adhesion of contaminants, the contamination rate is slowed, but similarly occurs at the output end of the end surface protection member. Therefore, it is preferable that an end surface protection member is a structure which can be detachable so that maintenance management may be possible.

Optical contact is mentioned as a connection method which connects the light exit end surface and end surface protection member of an optical fiber, and makes an end surface protection member removable, without requiring heat softening process, such as a fusion technique. Although optical contacts may be used for guiding light having high energy density, especially short wavelength light of 450 nm or less, or performing UV cleaning treatment used to remove contaminants at the emission end of the optical fiber, optical fibers may be used in contact portions. It is confirmed by the present applicant that it is difficult to form a detachable structure, because the constituent materials (quartz, SiO _2, etc.) of the end surface protection member cause some reaction and break each other's contact surfaces when detaching.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an optical fiber end surface protection structure capable of collectively protecting the end surfaces of a plurality of optical fibers and to which the end surface protection member is detachable, and a fiber bundle having the same. It is.

The optical fiber end surface protection structure of the present invention comprises a plurality of optical fibers for emitting incident light from the light exit end;

A translucent optical member having a refractive index substantially the same as that of the core materials of the plurality of optical fibers and allowing light emitted from the light exiting ends of the plurality of optical fibers to enter and exit from the light incidence end;

As an optical fiber end surface protection structure which has a protective medium interposed between the light output end of the said several optical fiber, and the light incident end of the said translucent optical member, and suppresses adhesion | attachment of the said light output end and the said light incident end,

The light incident end surface of the translucent optical member has a size equal to or greater than the light exit end surfaces of the plurality of optical fibers,

The plurality of optical fibers and the light transmitting optical member can be detachable through the protective medium.

In this specification, the "transparent optical member" is defined as an optical member having a transmittance of 90% or more in the wavelength of light incident on the optical member.

In addition, "the protective medium which suppresses the adhesion | attachment of the said light exit end and the said light incident end" is a contact part of the light exit end and the light incident end which are in physical contact state at normal temperature, and each component material produces a chemical reaction, A protective medium which prevents adhesion by means of a light, and the like, wherein the light emitting end and the light incident end are contacted with a load of 500 g and then separated or adhered to each other at the end portions of the contact portion when moved relatively from the contact portion. Or it is defined that adhesion is suppressed so that the surface unevenness | corrugation by a deposit will be (lambda) / 2 or less ((lambda) is an oscillation wavelength of incident light).

In addition, the light incidence end face of the translucent optical member is at least in contact with all the light output end faces of the plurality of optical fibers. It means to be size.

The optical fiber end surface protection structure of the present invention can be detachable even when the incident light is light having a wavelength of 190 nm to 530 nm.

It is preferable that the said protective medium has light transmittance with respect to the oscillation wavelength of the said incident light, and it is preferable that the optical path length of an optical waveguide direction is an integer multiple of (lambda) / 2.

In this specification, "the said protective medium has light transmittance with respect to the oscillation wavelength of the said incident light" means that transmittance | permeability with respect to the oscillation wavelength of incident light is 90% or more.

As said protective medium, it is a film | membrane body which consists of a multilayer film in which a single | mono layer film | membrane or some film | membrane was laminated | stacked, and what is formed in the surface of the light exit end of the said some optical fiber, and / or the light incident end of the said translucent optical member is mentioned.

Preferable that the protective medium containing a fluoride _{and, YF 3, LiF, MgF 2} , NaF, LaF 3, BaF 2, CaF 2 , and more preferably containing a fluoride of at least one member selected from the group consisting of AlF ₃ Do.

In addition, the optical fiber end surface protection structure of the present invention is such that the plurality of optical fibers are arranged at the output end side of the optical fiber so that the plurality of optical fibers accumulate and emit a plurality of light incident on the plurality of optical fibers. It is preferably applicable in the case of bundled fiber bundles.

The fiber bundle of the present invention has the optical fiber end surface protection structure of the present invention.

According to a preferred embodiment of the fiber bundle of the present invention, an integrated function fiber bundle portion in which the plurality of optical fibers are arranged and bundled at the output end side of the optical fiber so as to accumulate and emit a plurality of incident light incident to the plurality of optical fibers individually ,

A first fiber bundle having a uniform function fiber part for uniformly emitting the light emitted from the integrated function fiber bundle part;

A fiber bundle comprising a second fiber bundle in which the first fiber bundle is arranged and bundled at an exit end side of the first fiber bundle so as to aggregate and emit a plurality of the first fiber bundles,

The uniform function fiber part is made of an optical fiber having a core part larger than the light exit area in the light exit end face of the integrated function fiber bundle part at least in the light incident end face of the uniform function fiber part,

The light output end of the integrated function fiber bundle part and the light incident end of the uniform function fiber part are in contact with each other,

And a fiber bundle in which the integrated function fiber bundle portion and the uniform function fiber portion are detachable.

Moreover, as another preferable aspect of the fiber bundle of this invention, the some incident light which separately injected into the some optical fiber at the light incidence end of the at least 1 optical fiber of the some optical fiber which comprises the said integrated function fiber bundle part. The light output end of the second integrated function fiber bundle portion in which the plurality of optical fibers are arranged and bundled at the output end side of the optical fiber so as to accumulate the light is emitted through a protective medium that suppresses adhesion between the light output end and the light incident end. In contact,

The at least one optical fiber has a core portion larger than a light emission area at a light exit end face of the second integrated function fiber bundle portion at a light incident end face of the optical fiber,

And a fiber bundle in which the at least one optical fiber and the second integrated function fiber bundle unit are detachable.

Effect of the Invention

The optical fiber end face protection structure of the present invention has a structure in which the light exit end of the plurality of optical fibers and the light incidence end of the light transmissive optical member are contacted through a protection medium that suppresses adhesion. It is removable. In such a configuration, the plurality of optical fiber light exit end faces can be collectively protected and contacted via a protective medium that suppresses adhesion of the light transmitting end faces of the light transmitting optical members and the plurality of optical fibers, Even when the waveguide is short-wave light of 450 nm or less, or high energy density light, or when UV cleaning is performed on the end surface, the optically transmissive optical member can be removed without damaging the end surface. Can be. Therefore, according to this invention, the light output end surface of a some optical fiber can be collectively protected, and the optical fiber end surface protection structure which an end surface protection member can attach or detach can be provided.

`` Optical fiber end face protection structure, fiber bundle ''

The optical fiber end surface protection structure and the fiber bundle of one Embodiment of this invention are demonstrated with reference to drawings. 1 is an optical waveguide direction cross-sectional view of the optical fiber end surface protection structure 1 of the present embodiment. In this specification, in order to make it easy to see visually, the scale of a component is suitably different from an actual thing.

As shown in FIG. 1, the optical fiber end surface protection structure 1 is an end surface protection structure of the fiber bundle (plural optical fibers) 2, and the fiber bundle 2, the translucent optical member 3, And the sleeve (holding member) 4 and the like, and the light exit end face of the fiber bundle 2 is protected by the light transmitting optical member 3.

The light exit end 21 side of the fiber bundle 2 is inserted into the ferrol 2a, and the light exit end surface 21a is polished and processed. The end face shape of the light output end face 21a is not particularly limited as long as it is a shape that reduces connection loss, and may be processed into a hemispherical shape, a planar shape, or the like. A protective film (protective medium) 10 is formed on the light incident end surface 31a of the light transmitting optical member 3, and the light output end 21 and the light transmitting optical member 21 of the fiber bundle 2 are formed in the sleeve 4. The light incident end 31 of (3) is in contact with the optical contact through the protective film 10. As for the contact pressure in a contact part, about 4.9 N-about 11.8 N are preferable. Since the fiber bundle 2 and the translucent optical member 3 are in contact with each other by optical contacts, the optical fiber end face protection structure 1 is detachable from the fiber bundle 2 and the translucent optical member 3.

The light L1 guided in the fiber bundle 2 is emitted from the light exit end 21 of the fiber bundle 2, and is transmitted from the light incident end 31 through the protective film 10 to the translucent optical member 3. It enters inside, and it exits from the light output end 32 (L2).

The material of the fiber bundle 2 is not specifically limited, What is necessary is just to select a suitable material according to the wavelength of the light to guide. For example, in the case of guiding ultraviolet light, the optical fiber constituting the fiber bundle 2 is preferably a glass-based optical fiber composed mainly of SiO ₂ , quartz, or the like.

The material of the translucent optical member 3 may be one having a refractive index substantially the same as that of the core material of the fiber bundle 2, and similarly to the fiber bundle 2, a preferable material can be selected according to the wavelength of light to be guided.

The protective film 10 is a film formed on the light incidence end surface 31a and suppresses adhesion of the light exit end 21 of the fiber bundle 2 to the light entrance end 31 of the light transmitting optical member 3. will be. The protective film 10 may be formed directly on the light incident end surface 31a or may be formed through an assist film. When contacting glass-based optical members such as SiO ₂ or quartz with optical contacts, the light to be guided is light having high energy density or ultraviolet light, for example, light having an oscillation wavelength of 190 nm to 530 nm, or UV to the contact surface. When the cleaning process is performed or the like, the oxides on both contact surfaces cause some reaction in the contact portion, and the reaction portions are integrally adhered to each other. After that, the portions attached to the contact portions are broken, resulting in increased light loss and unusable state. It is confirmed by this applicant as follows.

After UV-cleaning an optical fiber and glass in FIG. 2, the contact surface of the optical fiber 100 when the end surface of the said optical fiber and the glass were contacted with the weight of about 500 [g], and left to stand for about 100 hours is shown. 101 is a clad and 102 is a core. 103 denotes a location where the optical fiber 100 and the glass (not shown) are contacted and pressed after washing, whereby the optical fiber 100 and the quartz or oxide contained in the glass react with each other, and the optical fiber 100 and the glass are integrated. Part. When the reaction points are integrated in this manner, when the optical fiber 100 and the glass are separated from each other, the reaction points are largely damaged or the reaction points are attached to the end face or the glass of the optical fiber 100. In addition, the surface roughness of the fiber before contacting is Ra = 2 [nm]. This phenomenon occurred even when the optical fiber was brought into contact with the optical contact. The above phenomenon is more likely to occur when surface roughness is less than Ra < 5 [nm] and when light of short wavelength with high energy density is guided.

Since the protective film 10 is for preventing the above phenomenon, it has light transmittance with respect to the oscillation wavelength λ of the incident light L1, and the fiber bundle 2 and the light transmitting optical member 3 are made of SiO ₂ , quartz, or the like. In the case of a glass material having a main component as a main component, it is preferable to suppress the adhesion of the light exit end 21 and the light incident end 31 when these are brought into physical contact at normal temperature. Therefore, the protective film 10 is preferably inert to light having a wavelength of 190 nm to 530 nm without easily reacting with SiO ₂ or quartz contained in the fiber bundle 2 and the transparent optical member 3. The thing containing is mentioned. As the fluoride, and preferably does not contain oxygen _{(O), YF 3, LiF} , MgF 2, NaF, LaF 3, BaF 2, CaF 2 , and more preferably at least one type of fluoride selected from the group consisting of AlF ₃ . These fluorides are inactive with respect to light with a wavelength of 190 nm to 410 nm, and their activities are small even with a wavelength of 410 nm to 530 nm. Further, as the wavelength becomes longer, the energy density also decreases, so that the protective film 10 suitable for light having a wavelength of 410 nm or more can be formed.

The protective film 10 may be a single layer film or a multilayer film. In the case of a multilayer film, the uppermost layer of the protective film 10 preferably contains the above-mentioned material, and the lower layer films other than the uppermost film preferably contain an oxide not containing Si.

In addition, since light loss by the presence of the protective film 10 is preferable, it is preferable that it is a material with little light absorption with respect to the wavelength of the light to be guided. Fig. 3 shows the relationship between the absorption coefficients and the damage thresholds of various fluoride films and oxide films when a pulse laser having a wavelength of 248 nm is used ("High damage threshold fluoride UV mirrors made by Ion Beam Sputtering", J. Dijion , et., al., SPIE Vol. 3244, pp406-418, 1998 ". From this graph, the fluoride film has a high damage threshold for ultraviolet light, and therefore the material of the protective film 10 also in terms of light absorption. In the case where the light to be guided is ultraviolet light, YF ₃ , LiF, and the like are more preferable in the fluoride film, as shown in the graph, because the damage threshold value is higher.

By setting it as the protective film 10 of the above structure, the chemical reaction in the contact part of the fiber bundle 2 and the translucent optical member 3 can be prevented, and the damage of a contact part can be suppressed. For example, the fiber bundle 2 and the optically transmissive optical member 3 can be reused, i.e., detachable even after being pressed against a contact portion with a load of 50 g or more and 1 kg or less (more preferably, 500 g or less). It can be done.

The light incidence end face 31a is a light output end face so that all the light emitted from the light output end 21 of the fiber bundle 2 is incident on the light incidence end 31 of the light transmitting optical member 3 at the contact portion. 21a) or more. 4 is a rod-shaped shape of the light transmitting optical member 3, and a plurality of optical fibers are arranged in a line (one-dimensional) and bundled in the fiber bundle 2 at the exit end (FIG. 4 (a)). And a cross section of the light exit end face 21a and the light incident end face 31a by taking the case of being bundled in a concentric shape (two-dimensional image) (Fig. 4 (b)) as an example. In FIG. 4, the light emission area | region in the light emission end surface 21a and the light entrance area | region of the light incident end surface 31a are shown with the oblique line. Although the light exit end surface 21a should have the area larger than the oblique part of the light incident end surface 31a, when the translucent optical member 3 is rod-shaped, the shape of the light incident end surface 31a is circular. Therefore, as shown in the figure, it has a size equal to or larger than the circumscribed circle of the light exit end 21a including all the light exit areas.

It is preferable that the light transmissive optical member 3 can emit all the incident light L1 from the light output end 32. Since the light becomes wider as the thickness in the waveguide increases, the size of the light exit end face 32a is preferably determined in consideration of the numerical aperture and the thickness of the fiber bundle 2.

When the light exit end face 21 of the fiber bundle 2 is protected by the light transmitting optical member 3, adhesion of dust or contaminants to the exit end face 21a hardly occurs, but instead light exit The end surface 32a becomes an adhesion surface of dust or contaminants. Since the adhesion of dust and contaminants is less likely to occur as the power density of light is lower, the larger the thickness of the light-transmitting optical member 3 in the waveguide direction is, and the larger the size of the light exit end face 32a is, the more the power of light is dispersed and the contamination rate is increased. Can slow down. Therefore, it is preferable that the light output end surface 32a is larger.

The shape of the translucent optical member 3 is not particularly limited as long as it has the light exit end surface 32a as described above, but the light incident end surface 31a and the light exit end surface ( The rod-shaped optical member of which 32a) is substantially the same is mentioned. In the case of a rod shape, when the light output end surface 32a is to be enlarged, the light incident end surface 31a is also large.

As described in the background art, when fused, the size of the light incident end face of the end face protection member is limited, but the optical fiber end face protection structure 1 of the present embodiment is a translucent optical that is an end face protection member. The member 3 and the fiber bundle 2 are not fusion | melted, but it is a structure which can contact and attach and detach. Therefore, there is no restriction | limiting in the magnitude | size of the light incident end surface 31a of the translucent optical member 3 which is an end surface protection member, For example, in the light output end surface 21a of the fiber bundle 2 in FIG. It is also possible to contact the translucent optical member 3 having a diameter of at least two times the diameter of the circumscribed circle of the light output area. Therefore, although the optical fiber end surface protection structure which collectively protects several fibers like the fiber bundle 2 can be set, the light incident end surface 31a is made larger and the contamination rate of the light output end surface 32a is improved. The translucent optical member 3 can be designed so that it can fully be reduced.

In addition, in the background art, when transmitting high output light, the optical fiber adversely affects the optical fiber itself and the connected optical device by generating a so-called return light in which a part of the waveguide light is reflected on the light exit end surface, and is returned to the optical fiber. It is also described that there is a case. Therefore, it is preferable that the light output end surface 32a is given the special process of anti-reflection. However, if the power of the light becomes large, the amount of returned light exceeds the range in which the influence on the optical fiber and the like can be ignored even if the anti-reflection special treatment is performed, so that the reflected light at the light exit end surface is re-entered into the optical fiber as much as possible. It is preferable that it can radiate | emit outward from an end surface protection member, without making it impossible. As described above, if the aperture of the translucent optical member 3 that is the end face protection member can be made larger, more reflected light can be emitted from the end face protection member to the outside without effectively reincident to the optical fiber. According to the embodiment, the influence by the return light can also be reduced.

In the present embodiment, the protective film 10 is formed on the light incident end surface 31a of the light transmissive optical member 3, but may be formed on the light exit end surface 21a of the fiber bundle 2. Films may be formed on both of the incident end face 31a and the light exit end face 21a.

It is preferable that the protective film 10 does not peel from the end surface formed into a film at the time of attaching and detaching the transparent optical member 3 and the fiber bundle 2. Therefore, when the protective film 10 is formed on either the light output end surface 21a or the light incident end surface 31a, the adhesion between the end face on which the protective film 10 is formed and the protective film 10 is formed. It is preferable that the end surface of the side where the protective film 10 is not formed is higher than the adhesiveness of the protective film 10. In the case where the film is formed on both end faces, the adhesion between the end face on which the protective film 10 is formed and the protective film 10 is preferably higher than the adhesion between the films formed on both end faces. In addition, when the protective film 10 is a multilayer film, it is preferable that adhesiveness is also high also about the film | membrane which comprises a multilayer film.

Light loss due to the presence of the protective film 10 is affected by the film thickness in addition to the material of the protective film 10 described above. Therefore, it is preferable that the film thickness of the protective film 10 is made into the film thickness which does not affect light loss. As a factor of the optical loss in the protective film 10, the loss by reflection and the loss by absorption are mentioned. Therefore, it is preferable to determine the film thickness of the protective film 10 in consideration of the influence on the light loss by reflection and absorption.

In order to minimize the loss due to reflection, the film thickness of the protective film 10 is preferably set to a film thickness that does not affect the light loss. When the protective film 10 is formed on either the light incident end surface 31a or the light output end surface 21a of the fiber bundle 2, the optical path length (d × N) in the optical waveguide direction of the protective film 10 is formed. Where d is the film thickness in the optical waveguide direction, N is the refractive index of the protective film 10), and the wavelength? Of the light to be guided satisfies the following formula (1).

d × N = (λ / 2) × n (One)

(Where n is an integer of 1 or more)

When the protective film 10 is formed on both the light incident end surface 31a or the light output end surface 21a of the fiber bundle 2, when the protective film 10 formed on both sides has the same refractive index ( What is necessary is just to make d into the total film thickness of the protective film 10 in Formula 1). However, when the film is formed on both sides, the protective film 10 formed on each end surface of the protective film formed on both end faces does not cause reaction or integration due to contact with each other. It is desirable to be. In this case, the film thickness of the protective film 10 formed on the light exit end 21a of the fiber bundle 2 is d _f , the refractive index is N _f , and the light incident end of the light transmissive optical member 3 ( When the film thickness of the protective film 10 formed on 31a) is set to d _g and the refractive index is equal to N _g , it is preferable that they satisfy the following formula (2).

(d _f × N _f ) + (d _g × N _g ) = (λ / 2) × n... (2)

(Where n is an integer of 1 or more)

In order to reduce the loss due to absorption, the protective film 10 is preferably thinner. The greater the film thickness, the greater the absorption of light energy of the film, and thus the protective film 10 is thermally deteriorated by the absorbed energy, which tends to cause discoloration, cracking, and the like. Therefore, it is preferable that n is 1 in said Formula (1) and (2). However, depending on the degree of the effect on the loss due to absorption, the effect by absorption becomes larger than the effect by reflection. In that case, light loss can be made smaller in the film thickness thinner than the film thickness when n = 1 in said Formula (1) and (2).

In order to investigate the preferable film thickness of the protective film 10, the optical device 110 shown in FIG. 5 was produced, and the time-dependent change of the light output of the emitted light when the protective film 10 of another film thickness was used was measured. . As shown in the figure, the optical device 110 is composed of optical fibers 111a and 111b, ferrules 112a and 112b, a sleeve 113, and the like, and the light inserted into each ferrule into the sleeve 113. The fibers 111a and 111b are in contact with each other via the protective film 10 having a film thickness d. In the contact surface, the end portion of the ferrol is polished into a hemispherical shape, and the protective film 10 is formed on the end surface on the optical fiber 111a side.

Using the optical device 110 having the film thickness d of the protective film 10 as λ / 2, λ / 4, and λ / 6, laser light having a wavelength of 405 nm and an output of 160 kHz was applied to the optical fiber 91a. The time-dependent change of the light output of the emitted light from the optical fiber 91b at the time of incident was measured. As a film-forming method of the protective film 10, the vapor deposition method was used. 6 is a diagram showing the result of the measurement, and the vertical axis represents the ratio of the output value of the emitted light to the output value of the incident light. At this time, laser light passes through an area of about 60 탆 in diameter in each film.

As shown in Fig. 6, the smaller the film thickness d, the lower the decrease in the light output of the emitted light (i.e., the less the light loss). In addition, as a result of microscopic observation of each protective film 10 after the experiment, almost no change in the appearance of the film of d = λ / 6 was observed, but the films of d = λ / 4 and λ / 2 were considered to be the passage portions of the laser light. Discoloration of was confirmed. In addition, in the film | membrane of d = (lambda) / 2, the crack of the film | membrane was confirmed around the discolored part. The discoloration seen in the films of d = λ / 2 and d = λ / 4 is considered to be because the film was melted by heat of laser light (thermal deterioration). From this result, it is thought that the larger the film thickness d, the larger the energy absorption of the laser light by the film, and the film quality is changed by this absorption, resulting in greater light loss.

7 shows the result of measuring the time-dependent change in the light loss value with the MgF ₂ films having d = λ / 6 and λ / 12 as the film thicknesses of the protective film 10. The film formation of the protective film 10 was performed by the ion assist method. As shown in Fig. 7, the method of changing the light output is almost the same in the films of d = λ / 6 and d = λ / 12, and the reduction rate of the light output of the emitted light after 1000 hours is less than 10%.

From these results, when the protective film 10 is an MgF ₂ film and the incident light is a laser light having a wavelength of 405 nm and an output of 160 Hz, the effect on light loss is greater than the effect by reflection, If the film thickness d of the protective film 10 is (lambda) / 6 or less, the fall rate of the light output of the emitted light after 1000 hours can be suppressed to less than 10%, and it is considered preferable.

The ratio of the influence of the reflection to the light loss and the influence of the absorption depends on the output or wavelength of the laser light and the material of the protective film 10, and the film thickness satisfying the formula (1) or (2) is In some cases, the film thickness d is preferably lambda / 6 or less. However, since light with a wavelength of 190 nm to 530 nm has a high energy density, it is considered that the film thickness d of the protective film 10 is preferably lambda / 6 or less, although it depends on the output. In the case where the protective film 10 is formed on both the light incident end face and the light exit end face at the contact portion, the film thickness is the sum of the film thicknesses of the protective film 10 formed on both sides (d = d). _f + d _g ).

Although the film formation method of the protective film 10 is not restrict | limited, In order to reduce the light loss in the interface of the protective film 10 and the end surface formed into a film, the film-forming method which can clean the film-formation surface before film-forming is preferable. In addition, the higher the density of the film, the smaller the change in film quality due to the energy absorption of the light of the protective film 10 itself when the light having high optical energy density is guided. Thus, a film forming method capable of forming a more dense film is preferable. As the film formation method which can clean the film-formed surface before film-forming and can form a high-density film | membrane, an ion assist method, an ion plating method, sputtering method, etc. are mentioned.

As the film forming method which can clean the film formation surface before the film formation and can form a film with high density, an ion assist method, an ion plating method, a sputtering method, and the like can be given.

Fig. 8 shows the results of measuring the time-dependent change in the light loss value using the protective film 10 (MgF ₂ film) having a film thickness λ / 6 formed by the deposition method and the ion assist method, respectively, in the same manner as the above measurement. will be. As shown in FIG. 8, it is understood that the use of the protective film 10 formed by the ion assist method is smaller than that of the vapor deposition method because the decrease in light output is smaller.

The number of optical fibers 20 bundled in the fiber bundle 2 and the arrangement pattern in the bundle portion are not particularly limited. The bundle portion may be one-dimensional (line), two-dimensional (including concentric circles), or the like, and may be arranged in accordance with the required emission pattern. Examples of the arrangement pattern are shown in Figs. 9A to 9D.

As a preferable form of the fiber bundle 2, the fiber bundle 4 shown in FIG. 10 is mentioned. The fiber bundle 4 is demonstrated with reference to FIG. 10 is a schematic sectional view of an optical waveguide direction of the fiber bundle 4.

The fiber bundle 4 is an integrated in which a plurality of optical fibers 50 are arranged and bundled at the light exiting end 52 side so as to integrate and output a plurality of incident lights L1 that are individually incident on the plurality of optical fibers 50. First fiber bundle portion 7 having a functional fiber bundle portion 5 and a uniform function fiber portion 6 having an optical fiber 60 which equalizes and outputs the light emitted from the integrated function fiber bundle portion 5. ) And the uniformly functional fiber portion 7 of the plurality of first fiber bundle portions arranged and bundled at the light exiting end 82 side so as to accumulate and output the light emitted from the plurality of first fiber bundle portions 7. It is provided with the 2 fiber bundle part 8.

In FIG. 10, the light exit end 52 of the integrated function fiber bundle part 5 and the light incident end 61 of the uniform function fiber part 6 are respectively attached to the ferrules 60a and 70a (not shown in FIG. 10). It is inserted in contact with the optical contact via the protective film 10 in the sleeve 80 (holding member). Therefore, the integrated function fiber bundle 5 and the uniform function fiber 6 are detachable.

Both end faces inserted into the ferrols 50a and 60a are polished, and the end face shape is not particularly limited as long as the connection loss is small, and a hemispherical shape, a planar shape, and the like can be given. In the case of using SC ferrol as the ferrols 50a and 60a, an SC connector can be used as the sleeve 80.

FIG. 11 is an enlarged cross-sectional view of a contact portion between the light output end 52 of the integrated function fiber bundle part 5 of FIG. 10 and the light incident end 61 of the uniform function fiber part 6, and FIG. It is a schematic diagram of the light output end surface 52a of the integrated function fiber bundle part 5, and the light incidence end 61a of the uniform function fiber part 6. As shown in FIG. As shown in FIG. 12, the optical fiber 60 of the uniform function fiber part 6 is at least at the light exit end surface 52a of the integrated function fiber bundle part 5 in the light incident end surface 61a. Has a core portion 61r having a size equal to or larger than the light emission region 52r. With such a configuration, the uniform function fiber portion 6 can receive all the light emitted from the integrated function fiber bundle portion 5, make it uniform, and output it.

Material system of the plurality of optical fibers 50 is not particularly limited and can be exemplified by a glass-based optical fiber and so on consisting primarily of SiO _2, quartz, it is possible to select a preferred material in accordance with the wavelength of the incident light (L1). Although the kind of optical fiber is not specifically limited, Multi-mode optical fiber is preferable when using for a light source etc. is considered.

Since the some optical fiber 50 comprises the integration function fiber bundle part 5, it is preferable that the fiber diameter is narrower so that it may be integrated more densely. However, as the optical fiber becomes thinner, the handling becomes more difficult, and the degree of freedom in design is limited, such as the length of the fiber and the difficulty in handling and the yield in production. In addition, as described in the background art, fiber bundles in which very narrow optical fibers are integrated at a high density are very difficult to cable. Therefore, it is desirable to be able to form the integrated structure by the coarse optical fiber of diameter as much as possible. The fiber bundle 5 has a two-stage integrated structure that further bundles and integrates the uniform function fiber portion 6 for uniformly emitting the light emitted from the integrated function fiber bundle portion 5 and outputs it. Therefore, when the required amount of light is determined, the number of optical fibers to be integrated at one time becomes smaller than that of the conventional single integrated structure. That is, it is possible to form the integrated function fiber bundle portion 5 by the large diameter optical fiber as compared with the single integrated structure. For example, in the case of a single integrated structure, when an optical fiber with an outer diameter of about 50 mu m is integrated, it is possible to have an outer diameter of about 80 mu m in the configuration shown in FIG. If it has such a fiber diameter, fiber length can also be set to about 50 cm-1 m which is easy to handle.

In addition, when the number of optical fibers to be integrated is large, for example, when the number of optical fibers exceeds 20, the handling is not easy, and therefore, the amount of the adhesive used to bundle the fibers is likely to be nonuniform, and the adhesive stain causes the optical bundle fiber to There is a possibility of affecting the polishing of the exit end surface and making the polishing state unstable. As described above, since the fiber bundle 4 can reduce the number of optical fibers to be integrated into the integration function fiber bundle portion 5, it may be difficult to cause adhesion stains. In addition, it is possible to increase the degree of integration while maintaining the number of integrations in an easy-to-handle number by using the multi-stage structure of the integrated functional fiber bundle as described later with respect to the demand for higher density.

The arrangement pattern of the plurality of optical fibers 50 in the integrated function fiber bundle part 5 is not particularly limited, but is arranged in such a way that the concentric circles (two-dimensional) shown in FIGS. 13A and 13B are closely packed together. When it is set as it is, it is easy to bundle a narrow optical fiber, and it is preferable. Since the final output pattern is determined by the arrangement pattern of the uniform function fiber section 6 in the light exit end 82 of the second fiber bundle section 8, the fiber bundle 4 has a concentric circular shape that is easy to integrate. It is possible to bind them into an array.

The uniform function fiber part 6 consists of one multi-mode optical fiber 60, and its material system is not particularly limited, but is emitted from the integrated function fiber bundle part 5 in which a plurality of optical fibers 50 are bundled. Since light is made uniform and radiate | emitted, it is preferable that it is an optical fiber of the same material system as the some optical fiber 50. FIG.

As mentioned above, since the integration function fiber bundle part 5 is a thing which integrated the narrow diameter fiber, when it is integrated at high density, fiber length cannot be made very long because of the difficulty of handling. The uniform function fiber part 6 emits the light emitted from the integrated function fiber bundle part 5 consisting of a plurality of lights, and the optical fiber 60 made of multi-mode fibers is caused by the interference of the light generated during the light guiding and the interaction between the modes. Since it is made to be uniform and it radiate | emitted, it is preferable that the length of the optical fiber 60 is longer. Therefore, the uniform function fiber part 6 can adjust the length of the whole fiber bundle. In consideration of light loss during light guiding, the length of the optical fiber 60 is preferably 10 cm or more and 5 m or less, and more preferably 1 m or more and 5 m or less.

Even if the light emitted from the uniform function fiber portion 6 measures its intensity distribution in a near field pattern, the uniformity is high. FIG. 14 shows a plurality of optical fiber 50 constituting the integrated functional fiber bundle 5, and uses four quartz-based multi-mode optical fibers having a core diameter of 60 µm and an outer diameter of 80 µm. This is a near field pattern of the outgoing light when light is incident on the first fiber bundle portion 7 produced by using a quartz-based multimode optical fiber having a core diameter of 230 µm and an outer diameter of 250 µm as the optical fiber 60. In Fig. 14, the vertical axis represents the maximum value of the emitted light as 1.0, and represents the intensity ratio with respect to the maximum value of the output light at each position. As shown in FIG. 14, the light emitted from the first fiber bundle portion 7 has a substantially uniform intensity distribution in the core portion. Therefore, even if only the structure of the 1st fiber bundle part 7 is provided, the fiber bundle with high uniformity of emitted light can be provided.

The light exit end of the fiber bundle 4 is the light exit end 82 of the second fiber bundle 8. Therefore, the emission pattern of the outgoing light L2 from the fiber bundle 4 can be changed by the arrangement of the optical fiber 60 of the uniform function fiber part 6 in the light output end 82 (Fig. See 9 (a)-(d).).

For example, when using it as a light source which irradiates the whole rectangular mirror, what is necessary is just to arrange | position the optical fiber 60 in the array pattern which closely contacted in one dimension as shown in FIG. In the case where the pattern shown in Fig. 9 (a) or (b) is to be integrated with only narrow-fiber fibers, it is likely to be a light emission pattern having a large number of invalid areas due to the difficulty in handling, and consequently to be a light source with poor uniformity. As described above, the fiber bundle 4 according to the present embodiment has a concentric circular arrangement that is easy to integrate in the integrated function fiber bundle part 5, and has a large-sized uniform function fiber part 6 that is easy to handle. Since the emission pattern can be formed by tying the optical fibers 60 in a desired arrangement, light can be emitted simply and with good uniformity.

As shown in Fig. 9 (d), when a plurality of lights are emitted from the separated emission positions, light having high uniformity can be emitted at each emission point.

The fiber bundle 4 has a configuration in which the integrated functional fiber bundle portion 5 and the uniform function fiber portion 6 are contacted by optical contacts. Therefore, the integrated function fiber bundle part 5 and the uniform function fiber part 6 can be easily attached or detached. In the case of the conventional single integrated structure, when one of the plurality of optical fibers constituting the fiber bundle exhibits a failure or deterioration, or when the specification as a light source is changed, the fiber bundle must be replaced for each fiber bundle. It is necessary to perform alignment again with the optical element or the like which causes incident light out of each other. Since the fiber bundle 4 of the present embodiment can be detached and replaced with only the integrated function fiber bundle part 5, maintenance management can be performed without moving the uniform function fiber part 6 side aligned with the optical element or the like. Can be.

For example, as shown in Fig. 9 (d), even if it is desired to set the output light intensity, the wavelength, or the like for each point, such as when two points are shined simultaneously and each is incident on a different optical system, they are connected to each point. Since only the integrated function fiber bundle portion 5 of the first fiber bundle portion 7 may be changed to one that meets the specification, the position adjustment of each point into the optical system is not performed each time, and is freely performed from each point. The characteristics of the light to be emitted can be changed.

As shown in FIG. 15, the fiber bundle 4 includes light of at least one optical fiber 50 of the plurality of optical fibers 50 constituting the integrated function fiber bundle portion 5 of the fiber bundle 4. At the incidence end 51, a plurality of optical fibers 90 are provided at the incidence end 92 of the optical fiber 90 so as to accumulate and output a plurality of incident lights L1 incident individually on the plurality of optical fibers 90. The light output end 92 of the 2nd integrated function fiber bundle part 9 arranged side by side was contacted (FIG. 16), and it can be set as the structure which multiplied the integrated function fiber bundle part. 15 shows an example in which the integrated functional fiber bundle unit has a two-stage structure. At this time, the at least one optical fiber 50 emits light at the light exit end surface 92a of the second integrated function fiber bundle portion 9 at the light incident end surface 51a of the optical fiber 50. It has the core part 51r larger than the area | region 92r (refer FIG. 12).

The second integrated fiber bundle portion 9 has the same configuration as the integrated function fiber bundle portion 5 of the fiber bundle 4, and the structure of the contact portion at the time of multiplexing is also the same as the fiber bundle 4. Therefore, as with the fiber bundle 4, since it is detachable and the integration function fiber bundle part is multi-stage, light can be integrated more densely. Although FIG. 15 shows the case where the integrated function fiber bundle part has a two-stage structure, it is possible to further increase the number of integrated function fiber bundle parts by the same configuration.

Also in the fiber bundle 4, when the light to be guided is short wavelength light or the like having a high optical energy density, the phenomenon of damaging the end face at the time of attaching and detaching at the contact portion occurs in the same manner. Therefore, in that case, it is preferable to interpose the protective film 10 at the contact point.

In the case where the integrated structure is multistage like the fiber bundle 4, since the influence of the return light occurs on each integrated part, there are many affected places. Therefore, the optical fiber end surface protection structure 1 can be used suitably for the fiber bundle 4.

The optical fiber end surface protection structure 1 is comprised as mentioned above.

The optical fiber end surface protection structure 1 is a protective medium in which the light exit end 21 of the fiber bundle (plural optical fibers) 2 and the light incident end 31 of the translucent optical member 3 suppress adhesion. It has a structure which contacted through 10), and the translucent optical member 3 which is an end surface protection member is removable. In such a structure, the light output end surface 21a of the fiber bundle 2 can be collectively protected, and also the protection medium 10 which suppresses the adhesion of the light transmitting optical member 3 and the light output end surface 21a. ), So that the end faces may be attached to each other at the time of attachment or detachment, even when the light having a short wavelength of 450 nm or less or high energy density that is easily The translucent optical member 3 can be attached or detached without being damaged. Therefore, according to this invention, the light output end surface 21a of the fiber bundle 2 can be collectively protected, and the optical fiber end surface protection structure 1 which an end surface protection member can attach or detach can be provided.

(Design change)

In the present embodiment, the fiber bundle is described as the plurality of optical fibers 2 as an example, but it is also applicable to other than the fiber bundle, for example, a fiber array.

In addition, although the case where the protective medium 10 is a film body was demonstrated, it is not limited to a film body.

EXAMPLE

An embodiment according to the present invention will be described.

Example 1

The optical fiber end surface protection structure shown in FIG. 1 was produced as follows.

First, a fiber bundle having a two-stage integrated structure shown in FIG. 10 was produced. As the optical fiber of the integrated function fiber bundle part, 12 quartz multi-mode glass optical fibers having a fiber length of 1 m, a core diameter of 60 μm, and an outer diameter of 80 μm are prepared, and four optical fibers are bundled at one end and bundled and bundled into three integrated fibers. A functional fiber bundle was produced. Bundling was performed by tying four optical fibers so as to be closely arranged in two dimensions as shown in Fig. 9A, and then fixing them with an adhesive.

Next, three quartz type multi-mode optical fibers having a core diameter of 205 µm and an outer diameter of 250 µm were prepared as optical fibers of the uniform function fiber portion, and one end of the three optical fibers was similarly bundled and bundled. Unlike the integrated functional fiber bundle portion, the arrangement in bundling is an arrangement in which lines are arranged in a line (one-dimensional) as shown in FIG. 13, and FC ferrules are attached to the exit end. The incident angle of the optical fiber end face has uniform features was formed a protective film composed of MgF _2.

After inserting into the SC ferrule at the light incidence end and the light exit end of the integrated function fiber bundle part, and the light incidence end of the uniform function fiber part, the light exit end of the integrated function fiber bundle part and the light incidence end of the uniform function fiber part are brought into contact with each other by means of an SC connector. A total of 12 fiber bundles were obtained.

Next, a quartz glass rod having a diameter of 6.5 mm and a length of 10 mm was prepared, an antireflection film was disposed on one end face, and a protective film made of an MgF ₂ film was formed on one end face to form an end face protection member. The optical fiber end surface protection structure was produced by making the light output end surface of a fiber bundle and the surface in which the protective film of the end surface protection member are formed into a sleeve in contact. FIG. 17: observes the exit end surface of the fiber bundle in a contact surface in the obtained optical fiber end surface protection structure from the emission end side of the optical fiber end surface protection structure.

Laser light having a wavelength of 405 nm and an output of 100 kW was incident on twelve light incidence ends of the fiber bundle of the obtained optical fiber end surface protection structure, and the time-dependent change in the output light power was measured (total input power 1.2 W).

(Example 2)

Similarly, a fiber bundle was made using an optical fiber having a core diameter larger than that of Example 1 (core diameter 230 µm and outer diameter 250 µm) as the optical fiber of the uniform function fiber portion, and the optical fiber end surface protection was performed by the same end surface protection member. Made a structure. In the same manner as in Example 1, the change over time of the emitted light power was measured.

(Example 3)

Using the optical fiber end surface protection structure similar to Example 1, the time-dependent change of the output light power was measured similarly, making total input power of incident light into 4.13W.

(Comparative Example 1)

The time-dependent change of the output light power was measured similarly to Example 1 about having no optical fiber end surface protection structure in the fiber bundle like Example 1. FIG.

(evaluation)

FIG. 18 shows the change over time of the emitted light power in Example 1 and Comparative Example 1. FIG. In FIG. 18, the vertical axis represents the maximum value of the emitted light as 1.0, and represents the intensity ratio with respect to the maximum value of the output light at each position. In Example 2, a fiber bundle having a larger diameter than that of Example 1 having a larger diameter than that of Example 1 was used. Since the same result as in Example 1 was obtained, illustration is omitted. As shown in the figure, the optical fiber end surface protection structure of Example 1 is hardly seen in the output optical power even after 300 hours, but in Comparative Example 1 which is not equipped with the optical fiber end surface protection structure, The output power is unstable and the output light power decreases over time. From these results, it was confirmed that the output end surface of the fiber bundle is protected by the optical fiber end surface protection structure, which effectively slows down the emission light power drop due to the end surface contamination. In addition, in Example 1, since output fall is hardly seen, it is thought that the optical fiber end surface protection structure can also effectively suppress deterioration of the fiber bundle by return light.

19 shows the change over time of the output light power in Example 3. FIG. FIG. 19 differs from FIG. 18 in that the vertical axis represents the output value of the emitted light. Also in Fig. 19, the decrease in the emitted light power is hardly seen even after 600 hours. Even when the total input power exceeded 4.0 W, it was confirmed that the optical fiber end face protection structure effectively delayed the emission light power drop due to the end face contamination.

From the above results, the usefulness of the optical fiber end surface protection structure of this invention was confirmed.

The optical fiber end surface protection structure of the present invention can be suitably used particularly as an end surface protection structure of the optical fiber and fiber bundle for ultraviolet light.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows the structure of the optical fiber end surface protection structure of embodiment which concerns on this invention.

2 is a cross-sectional view of a contact portion of an optical fiber in which a contact portion is bonded.

Fig. 3 is a graph showing the relationship between absorption coefficients and damage thresholds of pulse laser light having a wavelength of 248 nm between oxide films and fluoride films.

4 is a light exit end face of the fiber bundle and a light incident end face of the translucent optical member.

5 is a schematic cross-sectional view of principal parts of an optical device used for evaluation of light output characteristics of emitted light due to a difference in protective film.

It is a figure which shows the time-dependent change of the light output of the emitted light, when the film thickness of a protective film is set to (lambda) / 2, (lambda) / 4, (lambda) / 6.

It is a figure which shows the time-dependent change of the light output of emitted light when the film thickness of a protective film is set to (lambda) / 6 and (lambda) / 12.

It is a figure which shows the time-dependent change of the light output of the emitted light, when the deposition method of a protective film is made into the vapor deposition method and the ion assist method.

9 (a) to 9 (d) are diagrams showing the arrangement of the uniform functional fiber portions on the light exit end face of the fiber bundle.

It is sectional drawing which shows the structure of the fiber bundle of a preferable aspect in the optical fiber end surface protection structure of embodiment which concerns on this invention.

FIG. 11 is an enlarged cross-sectional view of the contact portion between the light output end of the integrated function fiber bundle portion and the light incident end of the uniform function fiber portion of the fiber bundle shown in FIG. 10.

FIG. 12 is a schematic view of the light exit end face of the integrated function fiber bundle part of the fiber bundle shown in FIG. 10 and the light incident end face of the uniform function fiber part. FIG.

13 (a) and 13 (b) are diagrams showing the arrangement in the light exit end face of the integrated function fiber bundle portion.

14 is the intensity distribution of the near field pattern of the emitted light from the uniform function fiber portion.

FIG. 15 is a cross-sectional view illustrating a configuration in a case where the integrated function fiber bundle portion of the fiber bundle of FIG. 10 has a multistage structure.

FIG. 16 is an enlarged cross-sectional view of the contact portion between the light output end of the second integrated function fiber bundle portion of the fiber bundle shown in FIG. 15 and the light incident end of the integrated function fiber bundle portion.

17 is an exit end face of the fiber bundle on the contact surface observed from the light exit end side of the optical fiber end face protection structure of Example 1. FIG.

It is a figure which shows the time-dependent change of the output light power in Example 1 and the comparative example 1. FIG.

19 is a diagram showing changes over time of the emitted light power in Example 3. FIG.

(Explanation of symbols for the main parts of the drawing)

1: optical fiber end face protection structure

10: protective film (protective member)

2: fiber bundle (plural optical fibers)

21: Light exiting group of fiber bundles (plural optical fibers)

21a: light exit end surface of a fiber bundle (plural optical fibers)

3: translucent optical member

31: light incident end of the light transmitting optical member

31a: light incident end face of the light transmitting optical member

4: fiber bundle

5: Integrated function fiber bundle

50,60,90: optical fiber

51,91: light incident end

51r, 61r: Core part

52: light emitting end (light emitting end of the integrated function fiber bundle)

52a: Light exit end face of the integrated function fiber bundle

52r: Light exit area of the integrated function fiber bundle

6: uniform function fiber part

61: light incident end of the uniform function fiber portion

62: light emitting end of the uniform function fiber portion

61a: light incident end face of uniform function fiber part

7: first fiber bundle

8: second fiber bundle

82: light exit end of the second fiber bundle

82a: light exit end surface of the second fiber bundle part

9: second integrated function fiber bundle

92: light exit end of the second integrated function fiber bundle unit

92r: light emission area of the second integrated function fiber bundle part

L1: incident light

Claims (15)

A plurality of optical fibers for emitting incident light from the light exiting stage; A translucent optical member having an index of refraction substantially equal to that of the core materials of the plurality of optical fibers and allowing the light emitted from the light exit ends of the plurality of optical fibers to enter and exit from the light incident end; And As an optical fiber end surface protective structure having a protective medium interposed between the light exit end of the plurality of optical fibers and the light incidence end of the translucent optical member, the protective medium inhibiting adhesion of the light exit end and the light incidence end: The light incident end face of the light transmitting optical member has a size equal to or greater than the light exit end faces of the plurality of optical fibers; And said plurality of optical fibers and said translucent optical member are detachable through said protective medium. 2. The light transmissive optical member according to claim 1, wherein the translucent optical member has a light incident end surface having a size capable of injecting all the light emitted from the light exit ends of the plurality of optical fibers, and the light incident on the light incident end surface. An optical fiber end face protection structure, having a light exit end face having a size that can exit. 3. The protective medium according to claim 1 or 2, wherein the light exiting end and the light incidence end are separated even if the light exit end of the plurality of optical fibers and the light incidence end of the translucent optical member are separated after contact with a load of 500 g. An optical fiber end face protection structure, wherein the adhesion is suppressed to be reusable. The optical fiber end surface protection structure according to claim 1, wherein the incident light is light having a wavelength of 190 nm to 530 nm. The optical fiber end surface protection structure according to claim 1, wherein the protective medium has a light transmitting property with respect to an oscillation wavelength of the incident light. 2. The protective medium according to claim 1, wherein the protective medium is a film composed of a single layer film or a multilayer film in which a plurality of films are stacked, and is formed on the surface of the light exit end of the plurality of optical fibers and / or the light incident end of the light transmitting optical member. An optical fiber end surface protection structure, characterized in that. The optical fiber end face protection structure according to claim 1, wherein an optical path length in the optical waveguide direction of the protective medium is an integer multiple of lambda / 2, where lambda is an oscillation wavelength of the incident light. The optical fiber end surface protection structure according to claim 1, wherein the thickness of the protective medium in the optical waveguide direction is λ / 2 or less (where λ is an oscillation wavelength of the incident light). The optical fiber end face protection structure according to claim 1, wherein the protection medium contains fluoride. 10. The method of claim 9, wherein the protective medium is YF _3, LiF, MgF _2, NaF, LaF _3, BaF _2, CaF _2, and the optical fiber which is characterized by containing at least one fluoride selected from the group consisting of AlF ₃ End face protection structure. The optical fiber according to claim 1, wherein the plurality of optical fibers are fiber bundles in which the plurality of optical fibers are arranged and bundled at an exit end side of the optical fiber so as to accumulate and output a plurality of light incident on the plurality of optical fibers. An optical fiber end surface protection structure. The fiber bundle which has the optical fiber end surface protection structure of Claim 11. 13. The apparatus of claim 12, further comprising: an integrated functional fiber bundle unit in which the plurality of optical fibers are arranged and bundled at an output end side of the optical fiber so as to accumulate and emit a plurality of incident light incident to the plurality of optical fibers separately; A first fiber bundle having a uniform function fiber portion for uniformly emitting the light emitted from the integrated function fiber bundle portion; And A fiber bundle comprising a second fiber bundle in which the first fiber bundle is arranged and bundled at the exit end side of the first fiber bundle so as to aggregate and emit a plurality of the first fiber bundles: The uniform function fiber portion is made of an optical fiber having a core portion at least at the light incidence end face of the uniform function fiber portion than the light exit area in the light exit end face of the integrated function fiber bundle portion; The light exit end of the integrated function fiber bundle portion is in contact with the light incident end of the uniform function fiber portion; And the integrated function fiber bundle portion and the uniform function fiber portion are removable fiber bundles. 13. The light emitting device of claim 12, wherein the plurality of incident light beams that are individually incident on the plurality of optical fibers are integrated and emitted to the light incidence ends of the one or more optical fibers of the plurality of optical fibers constituting the integrated function fiber bundle unit. The optical exit ends of the second integrated function fiber bundle portions, in which the optical fibers of the optical fibers are bundled and arranged at the exit end side of the optical fiber, are in contact with each other through a protective medium for suppressing adhesion of the light exit end and the light incident end; The at least one optical fiber has a core portion larger than a light emitting area at a light exit end face of the second integrated functional fiber bundle portion at a light incident end face of the optical fiber; And the at least one optical fiber and the second integrated function fiber bundle portion are detachable fiber bundles. The light emitting end of the integrated function fiber bundle portion and the light incident end of the uniform function fiber portion are in contact with each other through a protective medium that suppresses adhesion of the light exit end and the light incident end. And said integrated function fiber bundle portion and said uniform function fiber portion are detachable through said protective medium.

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