KR20050023440A - Optical fiber component - Google Patents

Abstract

The optical fiber component of the present invention comprises an optical element 1, a pair of large MFDs (about 30 to 50 μm), a pair of PhC fibers 2a and 2b, and a pair of small MFDs (about 10 μm). 3a, 3b).

The pair of PhC fibers 2a and 2b includes cores 21a and 21b for transmitting light and clads 22a and 22b provided on the outer periphery of the cores 21a and 21b.

The output end of the first PhC fiber 2a is optically connected to the light incident end face 1a of the optical element 1 so as to coincide with the optical axis of the optical element 1, and the second PhC fiber is connected to the light exit end face 1b. The input end of 2b) is optically connected to coincide with the optical axis of the optical element 1. In addition, an output end of the first SM fiber 3a is optically connected to an input end of the first PhC fiber 2a to coincide with an optical axis of the first PhC fiber, and an output end of the second SM fiber 3b is connected to the output end of the second PhC fiber 3b. The input terminal is optically connected to coincide with the optical axis of the first PhC fiber.

Description

Optical Fiber Parts {OPTICAL FIBER COMPONENT}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to optical fiber components and, more particularly, to optical fiber components used for optical coupling portions between optical transmission paths and optical elements constituting the optical transmission system.

In general, an optical transmission system includes an optical transmission path or a bulk optical device (optical isolator, an optical switch, etc.), and in such an optical transmission path or bulk optical device, from an optical fiber constituting the optical transmission path. The light exiting is incident on the bulk optical device, and the light exiting from the bulk optical device is configured to enter the optical fiber again.

Here, the light exiting from the optical fiber is collimated by the lens, and the light exiting from the bulk device is condensed by the lens and configured to be incident on the optical fiber.

However, in the coupling of the light having such a configuration, in the case of using a single mode fiber (hereinafter, abbreviated as "SM fiber") having a small core diameter as an optical fiber, alignment of the SM fiber, the lens, and the bulk optical device There is a problem that the cost increases because the alignment is complicated.

For this reason, (a) as shown in FIG. 11, a pair of GRIN lens (Gradient Index Lens) 20a, 20b is arrange | positioned at the both ends of the bulk type optical device 10, and this green lens 20a, 20b is provided. Green lens system (see Japanese Patent Application Laid-Open No. 2001-75026, Japanese Patent Application Laid-Open No. Hei 11-52293), which disposes a pair of SM fibers 30a and 30b on both sides of the < RTI ID = 0.0 > A pair of optically connected end surfaces of one side of a pair of fibers (hereinafter, abbreviated as "TEC fibers") 40a and 40b subjected to TEC (Thermal Expanded Core) processing are optically connected to both ends of the optical device 10, respectively. TEC system (see Japanese Patent Application Laid-Open No. 63-33706), which is optically connected with SM fibers 30a and 30b, respectively, on the other end surface of the TEC fibers 40a and 40b, and (c) a bulk type as shown in FIG. Optical cross-sections on one side of a pair of graded index fibers (hereinafter abbreviated as "GI fibers") 50a and 50b are provided at both ends of the optical device 10. A GIF method in which the SM fibers 30a and 30b are optically connected to the other end surfaces of the pair of GI fibers 50a and 50b, respectively, has been proposed (J. Lightwave Technology VOL.LT.5). No.9 1987, J. Lightwave Technology VOL.20 NO.5 2002).

However, in the green lens method of (a), since the optical connection with the optical device is performed in a single mode, the connection loss is reduced and the components are inexpensive. However, the disadvantage is that the configuration is complicated, the process required for alignment is increased, and the overall cost is increased. have. In addition, in the TEC method of (b), since the core can be expanded in a single mode, the radiation loss of the TEC fiber portion is low, so that the low loss mode field diameter (hereinafter abbreviated as MFD) can be expanded. Since the connection loss is reduced because of optical connection with the optical device in the single mode, there are problems in that component parts are expensive, long time is required for TEC processing, and it is difficult to adjust the length of the TEC fiber parts. In addition, in the GIF method of (c), although the component is inexpensive and the size of the MFD or the length of the GI fiber can be adjusted according to the non-refractive index difference or the manufacturing conditions of the GI fiber with the core diameter, the optical device in a single mode is used. It is difficult to optically connect with the optical fiber, and it is difficult to finely adjust the length of the GI fiber because it is necessary to make the collimated light by adjusting the length of the GI fiber. There is a problem in that the connection loss between the opposing SM fiber and the GI fiber becomes large.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and by using a photonic crystal fiber (hereinafter, abbreviated as "PhC fiber"), it is possible to optically connect with an optical element in a single mode, and has a low connection loss. It is an object to provide an optical fiber component.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is an explanatory diagram showing a first embodiment of an optical fiber component of the present invention, Fig. 1A is a partial longitudinal cross-sectional view of the same optical fiber component, and Fig. 1B is an explanatory diagram of waveforms propagating through the same optical fiber component. .

2 is a cross-sectional view of a PhC fiber with an optical fiber component of the present invention.

3 is an explanatory view showing a second embodiment of the optical fiber component of the present invention, FIG. 3A is a partial cross-sectional view of the same optical fiber component, and FIG. 3B is an explanatory diagram of a wave propagating through the same optical fiber component.

4 is an explanatory diagram showing a third embodiment of the optical fiber component of the present invention, FIG. 4A is a partial cross-sectional view of the same optical fiber component, and FIG. 4B is an explanatory diagram of a wave propagating through the same optical fiber component.

5 is an explanatory diagram showing a fourth embodiment of the optical fiber component of the present invention, FIG. 5A is a partial cross-sectional view of the same optical fiber component, and FIG. 5B is an explanatory diagram of a wave propagating through the same optical fiber component.

6 is an explanatory diagram showing a fifth embodiment of the optical fiber component of the present invention, FIG. 6A is a partial cross-sectional view of the same optical fiber component, and FIG. 6B is an explanatory diagram of a wave propagating through the same optical fiber component.

Fig. 7 is an explanatory diagram showing a sixth embodiment of the optical fiber component of the present invention, Fig. 7A is a partial cross-sectional view of the same optical fiber component, and Fig. 7B is an explanatory diagram of a wave propagating through the same optical fiber component.

8 is an explanatory diagram showing a seventh embodiment of the optical fiber component of the present invention, FIG. 8A is a partial cross-sectional view of the same optical fiber component, and FIG. 8B is an explanatory diagram of a wave propagating through the same optical fiber component.

9 is an explanatory diagram showing an eighth embodiment of the optical fiber component of the present invention, FIG. 9A is a partial cross-sectional view of the same optical fiber component, and FIG. 9B is an explanatory diagram of a wave propagating through the same optical fiber component.

Fig. 10 is a plan view showing a ninth embodiment of an optical fiber part of the invention.

11 is a partial longitudinal sectional view of a conventional optical fiber component.

12 is a partial longitudinal sectional view of a conventional optical fiber component.

13 is a partial longitudinal sectional view of a conventional optical fiber component.

In order to achieve this object, the optical fiber component of the present invention is an optical element having a light incident cross section at one side and a light exit cross section at the other side, and one end surface of each side is optically connected to both end surfaces of the optical element. A pair of Photonic crystal Fibers (PhC fibers), and a pair of single mode (SM) fibers optically connected to one end surface of the other end surface of the pair of PhC fibers, The diameter of the mode field of the pair of photonic crystal fibers becomes relatively larger than the diameter of the mode field of the pair of single mode fibers, respectively.

In addition, the optical fiber component of the present invention includes an optical element having a light incident cross section at one side and a light exit cross section at the other side, and a pair of photonic crystals in which one end section is optically connected to both end surfaces of the optical element, respectively. One cross-section is optically connected to a fiber, a pair of single-mode fibers in which one end is optically connected to the other end face of the pair of photonic crystal fibers, and the other end face of the pair of collimated lenses, respectively. With a pair of single-mode fibers connected, the mode field diameters of a pair of photonic crystal fibers are respectively larger than the mode field diameters of a pair of single-mode fibers, and the mode field of a pair of collimated lenses. The diameters gradually expand from singlemode fibers toward the photonic crystal fibers, respectively.

Moreover, according to the optical fiber component of this invention, an optical element consists of an optical isolator, an optical filter, an optical switch, or an optical variable attenuator, or a combination thereof.

The optical fiber component of the present invention includes an SM fiber and a PhC in which one side cross section is optically connected to a cross section of one side of the SM fiber and the diameter of the MFD is relatively larger than the diameter of the MFD of the SM fiber, and the outer diameter of the PhC fiber The silver becomes substantially the same as the diameter of the ferrule constituting the optical connector.

In addition, in the optical fiber component of the present invention, one side cross section is optically connected to one side of the SM fiber, one side of the SM fiber, and one side cross section is to the cross section of the other side of the collimated lens and the collimated lens where the MFD is gradually enlarged. The MFD becomes relatively larger than the MFD diameter of the SM fiber, and the outer diameter of the PhC fiber becomes substantially the same as the diameter of the ferrule constituting the optical connector.

Moreover, according to the optical fiber component of this invention, a collimated lens can be comprised by the graded index fiber.

Moreover, according to the optical fiber component of this invention, it is possible to fuse the cross section of a GI fiber to the cross section of a PhC fiber.

Moreover, according to the optical fiber component of this invention, a connector housing can be attached to the front-end | tip of a PhC fiber.

Moreover, according to the optical fiber component of this invention, it is preferable that MFD of PhC fiber is at least 20 micrometers.

According to the optical fiber component of the present invention, the optical fiber component can be optically connected to the optical element in a single mode by using the PhC fiber, so that the connection loss can be reduced. In addition, according to the PhC fiber, since the size of the MFD can be freely designed, the core can be expanded in a single mode, and the optical coupling can be easily performed corresponding to the design of the optical element. In addition, the MFD of the PhC fiber can be made large, so that the diffraction angle of the total light is made small, and the connection loss can be made smaller when combined with the optical element.

EMBODIMENT OF THE INVENTION Hereinafter, preferred embodiment to which the optical fiber component of this invention is applied is described with reference to drawings.

1 is a partial longitudinal sectional view of an optical fiber component according to a first embodiment of the present invention, and FIG. 2 shows a cross sectional view of a PhC fiber.

In Fig. 1, the optical fiber component of the present invention comprises an optical variable attenuator such as an optical isolator, an optical filter, an optical switch, or the like, or a combination thereof, and a pair of large MFDs (about 30 to 50 µm). PhC fibers 2a, 2b and a pair of SM fibers 3a, 3b having a small MFD (about 10 μm) are provided. On one side of the optical element 1, a light incidence end surface 1a is provided, and on the other side, light is provided. The emission cross section 1b is provided. In addition, the pair of PhC fibers 2a and 2b includes cores 21a and 21b for propagating light and clads 22a and 22b provided on the outer periphery of the cores 21a and 21b. Similarly, a pair of SM fibers 3a and 3b also have cores 31a and 31b for propagating light and clads 32a and 32b provided on the outer periphery of the cores 31a and 31b, respectively.

Here, the PhC fibers 2a and 2b are glass tubes corresponding to the clads 22a and 22b around glass rods such as quartz, which correspond to the cores 21a and 21b, as shown in FIG. A free form mode in which glass tubes are regularly formed into a plurality of bundles, which are radial in fiber form. The cross sections of the cores 21a and 21b of the PhC fibers 2a and 2b form a circle or polygon (hexagonal shape or the like).

Such PhC fibers 2a and 2b have a large effective refractive index difference and core diameter in comparison with SM fibers which are generally used in adjusting the diameter or the distance between the holes of the glass tube corresponding to the clads 22a and 22b. It is possible to design freely, and it is equipped with a feature that can realize a large MFD in a single mode corresponding to the wavelength used.

Next, in the light incident end surface 1a of the optical element 1, the end face (output end) of one side of the PhC fiber 2a (hereinafter referred to as "first PhC fiber 2a") on the left side in the drawing is an optical element ( Optically connected to coincide with the optical axis of 1), an end surface (input end) of one side of the PhC fiber 2b (hereinafter referred to as the "second PhC fiber 2b") on the right side is shown in the light exit end face 1b. Optically connected to coincide with the optical axis of the optical element 1. In addition, a cross section (input end) of one side of the SM fiber 3a (hereinafter referred to as "first PhC fiber 3a") on the right side of the drawing is formed on the other end face (input end) of the first PhC fiber 2a. Optically connected to coincide with the optical axis of the 1 PhC fiber, the cross section of one side of the SM fiber 3b (hereinafter referred to as the "second SM fiber 3b") in the drawing on the other end face (output end) of the second PhC fiber. The (input end) is optically connected to coincide with the optical axis of the second PhC fiber 2b. Further, the first and second PhC fibers 2a and 2b and the first and second SM fibers 3a and 3b can be fusion-spliced by heating the mirror-connected connection cross sections on both sides with burners or arc discharges. In addition, between the output terminal of the first PhC fiber 2a and the optical element 1 and between the input terminal 2b of the second PhC fiber 2a and the optical element 1 are formed of an optical adhesive or a matching oil. Can be connected by application.

In the optical fiber component having such a configuration, as shown in FIG. 1B, the light incident from the input end of the first SM fiber 3a is transmitted through the first SM fiber 3a in a small MFD waveform 33a. It exits from the output terminal of the 1st SM fiber 3a. In addition, the light emitted from the first SM fiber 3a is incident on the input terminal of the first PhC fiber 2a and enlarged to the large MFD waveform 23a in the first PhC fiber 2a, and the first PhC in single mode. It propagates through the fiber 2a and enters the light incident end face 1a of the optical element 1. Then, the light passing through the optical element 1 and exiting from the light exit surface 1b thereof is incident on the input terminal of the second PhC fiber 2b, and the waveform of the large MFD is transmitted through the second PhC fiber 2b. And propagates to the single mode state and exits from the output end of the second PhC fiber 2b. In addition, the light emitted from the second PhC fiber 2b is incident on the input terminal of the second SM fiber 3b, and is reduced to a small MFD waveform 33b in the second SM fiber 3b, so that the second mode is operated in a single mode. It propagates through the SM fiber 3b.

Therefore, according to the optical fiber component according to the first embodiment, it is possible to optically connect with the optical element in the single mode, so that the connection loss can be reduced.

3 shows a longitudinal sectional view of a part of an optical fiber component according to a second embodiment of the present invention. In addition, the same reference numerals are added to parts common to those of FIGS. 1 and 2 in the same drawing, and a detailed description thereof will be omitted.

In Fig. 3, the fiber component according to the second embodiment has an optical element 1 having an incident end face 1a on one side and a light exit end face 1b on the other side, and the light incident on the optical element 1 An end surface (output end) of one side of the first PhC fiber 2a is optically connected to the end face 1a so as to coincide with the optical axis of the optical element 1, and the light exit end face 1b of the second PhC fiber 2b One end face (input end) is optically connected to coincide with the optical axis of the optical element 1. In addition, an end surface (output end) of one side of the first GI fiber 4a is optically connected to an end surface (input end) of the other side of the first PhC fiber 2a so as to coincide with an optical axis of the first PhC fiber 2a. The end face (input end) of the second GI fiber 4b is optically connected to the end face (output end) of the second PhC fiber 2b so as to coincide with the optical axis of the second PhC fiber 2b. Furthermore, the end face (input end) of one side of the first SM fiber 3a is optically connected to the end face (input end) of the other side of the first GI fiber 4a so as to coincide with the optical axis of the first GI fiber 4a. One end face (input end) of the second SM fiber 3b is optically connected to the other end face (output end) of the 2 GI fibers 4b so as to coincide with the optical axis of the second GI fiber 4b.

Here, the MFDs (about 30 to 50 µm) of the first and second PhC fibers 2a and 2b are larger than the MFDs (about 10 µm) of the first and second SM fibers 3a and 3b. The MFD of the second GI fibers 4a and 4b is about 10 μm to 30 to 50 from the respective first and second SM fibers 3a and 3b toward the corresponding first and second PhC fibers 2a and 2b. It gradually expands to about 탆.

In the optical fiber component according to the second embodiment, as shown in FIG. 3 (b), the light incident from the input terminal of the first SM fiber 3a is the first SM fiber 3a with a small MFD waveform 33a. It propagates through and exits from the output of the first SM fiber 3a. Further, the light emitted from the first SM fiber 3a is incident on the input terminal of the first GI fiber 4a, and the waveform 43a of the MFD in the first GI fiber 4a is about 30 to 50 µm at about 10 µm. It gradually expands to a degree and is incident on the input terminal of the first PhC fiber 2a. Therefore, the first PhC fiber 2a propagates through the first PhC fiber 2a in a single mode from the large MFD waveform 23a to be incident on the light incident end face 1a of the optical element 1. Then, the light passing through the optical element 1 and exiting from the light exit end face 1b thereof is incident on the input end of the second PhC fiber 2b, and the waveform of the large MFD is passed through the second PhC fiber 2b. It simultaneously propagates to the single mode state at 23b and exits from the output terminal of the second PhC fiber 2b. Further, light emitted from the second PhC fiber 2b is incident on the input terminal of the second GI fiber 4b, and the waveform 43b of the MFD in the second GI fiber 4b is about 10 to about 30 to 50 µm. It is gradually reduced to about 占 퐉, and is incident on the input terminal of the second SM fiber 3b, and propagates through the SM fiber 3b simultaneously in a single mode from the second SM fiber 3b to the small MFD waveform 33b. .

Therefore, the optical fiber component according to the second embodiment can also be optically connected to the optical element in a single mode, so that the connection loss can be reduced.

4 shows an explanatory diagram of an optical fiber component according to a third embodiment of the present invention. In addition, the same reference numerals are given to parts common to those in FIG. 3, and a detailed description thereof will be omitted.

In the optical fiber component according to the third embodiment, an optical isolator 1A is used as the optical element.

As a result of performing optical measurement in this embodiment, the loss between the first and second SM fibers 3a and 3b at a wavelength of 1550 nm was 0.5 Hz and the isolation was 45 Hz.

5 shows an explanatory diagram of an optical fiber component according to a fourth embodiment of the present invention. In addition, the same reference numerals are given to parts common to those in FIG. 3, and a detailed description thereof will be omitted.

In the optical fiber component according to the fourth embodiment, the optical variable attenuator 1B is used as the optical element.

As a result of performing optical measurement in this Example, the driving voltage was 0 to 10V and the variable attenuation amount was 0.5 to 25 Hz for a wavelength of 1550 nm.

6 shows an explanatory diagram of an optical fiber component according to a fifth embodiment of the present invention. In addition, the same reference numerals are given to parts common to those in FIG. 3, and detailed description thereof will be omitted.

In the optical fiber component according to the fifth embodiment, the optical switch 1C is used as the optical element.

As a result of performing optical measurement in this Example, the driving voltages were 0V and 10V for the wavelength 1550 nm, and the attenuation amounts were 0.5 Hz and 25 Hz.

7 shows an explanatory diagram of an optical fiber component according to a sixth embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the part which is common in FIG. 4 in the same figure, and detailed description is abbreviate | omitted.

In the optical fiber component according to the sixth embodiment, the first and second non-strippable primary coated (SM-NSP) fibers 3a ', instead of the first and second SM fibers 3a and 3b shown in FIG. 3b ') is used. Here, the SM-NSP fibers 3a 'and 3b' are optical fiber cores in which the NSP layer made of an unpeelable polymer resin is thinly coated (e.g., about 5 mu m) on the surface of a clad with an outer diameter of 115 mu m, for example. As a result, even after removing the coating, the NSP diameter is about 125 µm, which is equivalent to that of a normal SM fiber.

In this embodiment, the first and second SM-NSP fibers 3a 'and 3b', the first and second GI fibers 4a and 4b and the first and second, respectively, polished in cross section on the V groove. PhC fibers 2a, 2b are arranged, each cross section being fixed with mechanical splices. Here, a matching oil is applied to each cross section of these fibers.

As a result of performing optical measurements in this example, the insertion loss between the first and second SM-NSP fibers 3a 'and 3b' was 1 ms and the isolation was 42 ms for the wavelength 1550 nm.

8 shows an explanatory diagram of a fiber component according to a seventh embodiment of the present invention. In addition, the same reference numerals are given to parts common to those of FIGS. 1 to 3 in the same drawing, and a detailed description thereof will be omitted.

In FIG. 8, the optical fiber component according to the seventh embodiment includes a first PhC fiber 2a (or a second PhC fiber 2b) having a large MFD (about 30 to 50 µm) and an MFD (about 10 µm). Since the first SM fiber 3a (or the second SM fiber 3b) is small, the connection cross sections of both of them are the same as in the above-described embodiment, and are optically connected with their optical axes coincident with each other.

Here, the outer diameter D of the first PhC fiber 2a (or the second PhC fiber 2b) is, for example, a diameter (1.25 mm) of a ferrule (not shown) mounted on an optical connector such as an FC connector (not shown). Is actually the same as

In this embodiment, the outer diameter D of the first PhC fiber 2a (or the second PhC fiber 2b) becomes substantially the same as the diameter of the ferrule of the optical connector, thereby making it a connector type with the optical element 1. Optical coupling is possible.

9 shows an explanatory diagram of an optical fiber component according to an eighth embodiment of the present invention. In addition, the same reference numerals are added to parts common to those of FIGS. 1 to 3 and 8 in the same drawings, and detailed description thereof will be omitted.

9, the optical fiber component according to the eighth embodiment includes the first and second PhC fibers 2a and 2b of large MFD (about 30-50 mu m) and the first and second small MFDs (about 10 mu m). The second SM fibers 3a and 3b are provided, and the connection cross sections of the two are optically connected in the same manner as in the above-described embodiments, respectively, coinciding with both optical axes.

Here, the diameters D of the first and second PhC fibers 2a and 2b have the same diameter as the diameter of the ferrule, respectively, in the same form as the optical fiber component according to the third embodiment.

In this embodiment, the outer diameter D of the first and second PhC fibers 2a and 2b is made of a diameter substantially the same as the diameter of the ferrule of the optical connector, so that the first PhC fiber 2a is formed in the connector shape. Optical coupling of the second PhC fiber 2b can be easily performed.

10 shows an explanatory diagram of an optical fiber component according to a ninth embodiment of the present invention. In addition, the same reference numerals are given to parts common to those in FIGS. 1 to 3 and 8 to 9 in the same drawings, and detailed descriptions thereof will be omitted.

In FIG. 10, the optical fiber component according to the ninth embodiment includes a first PhC fiber 2a (or a second PhC fiber 2b) of large MFD (about 30 to 50 µm) and a small MFD (about 10 µm). The first SM fiber 3a (or the second SM fiber 3b) is provided, and the connection cross sections of both of them are optically connected in the same manner as in the above-described embodiment so as to coincide both optical axes. Here, the outer diameter of the first PhC fiber 2a (or the second PhC fiber 2b) has the same shape as that of the optical fiber component according to the third embodiment, and has a diameter substantially the same as the diameter of the ferrule.

In addition, the connector housing 5 is attached to the outer periphery of the end surface (front end) of one side of the first PhC fiber 2a (or the second PhC fiber 2b) via a spacer (not shown). The front end surface of the first PhC fiber 2a (or the second PhC fiber 2b) is disposed so as to slightly protrude from the cross section of the connector housing 5.

In this embodiment, the distal end portion of the first PhC fiber 2a (or the second PhC fiber 2b) is formed into a plug shape by attaching the connector housing 5 so that the corresponding first PhC fiber The distal end of 2a (or the second PhC fiber 2b) can be connected to an adapter (not shown).

Here, in the above-described embodiment, the case where the MFD of the PhC fiber is set to 30 to 50 µm has been described, but the MFD needs at least 20 µm. If it is less than 20 µm, optical condensation of the Phc fiber and the SM fiber (or GI fiber) may be difficult.

Also, in the above-described embodiment, the case where the first and second PhC fibers and the first and second SM fibers are optically connected is described. However, between the first and second PhC fibers and the first and second SM fibers, The first and second collimate lenses may be optically connected to each other.

Furthermore, in the above-described embodiment, the case where the outer diameters of the first and second PhC fibers and the outer diameters of the first and second GI fibers are set to the same diameter has been described, but the outer diameter of the former and the outer diameter of the latter can be different. .

As apparent from the above description, according to the optical fiber component of the present invention, by using the PhC fiber, optical connection can be made to the optical element in a single mode, thereby reducing the connection loss. In addition, according to the PhC fiber, since the size of the MFD can be freely designed, the core can be expanded in a single mode, and light coupling can be easily performed according to the design of the optical element. Moreover, the diffraction angle of the total light can be reduced by increasing the MFD of the PhC fiber, and the connection loss can be reduced when coupling to the optical element.

Claims (9)

An optical element having a light incident cross section at one side and a light exit cross section at the other side, a pair of photonic crystal fibers optically connected at both ends of the optical element to both cross sections of the optical element, and A pair of single-mode fibers in which one end surface is optically connected to each other end face of the pair of photonic crystal fibers, And a diameter of a mode field of the pair of photonic crystal fibers is relatively larger than a diameter of a mode field of the pair of single mode fibers. An optical element having a light incidence cross section at one side and a light exit cross section at the other side, a pair of photonic crystal fibers optically connected at both ends of the optical element at both ends, and the One pair of cross-sections are respectively provided in a pair of collimation lenses in which one side of the pair is optically connected to a cross-section of the other side of the pair of photonic crystal fibers, and in a cross-section of the other side of the pair of collimating lenses. With a pair of optically connected singlemode fibers, The mode field diameter of the pair of photonic crystal fibers is relatively larger than the mode field diameter of the pair of single mode fibers, respectively, and the mode field diameter of the pair of collimated lenses is determined from the single mode fiber. An optical fiber component, each gradually expanding toward a nicked crystal fiber. The optical fiber component according to claim 1 or 2, wherein the optical element is composed of an optical isolator, an optical filter, an optical switch or an optical variable attenuator or a combination thereof. A single-mode fiber and a photonic crystal fiber having one side cross section optically connected to a cross section of one side of the single mode fiber, the mode field diameter being relatively larger than the mode field diameter of the single mode fiber, An outer diameter of the photonic crystal fiber is substantially equal to a diameter of a ferrule constituting the optical connector. One side cross-section is optically connected to the single mode fiber, one side cross section is optically connected to the cross section of one side of the single mode fiber, and one side cross section is optically connected to the cross section of the other side of the collimated lens, and the mode field diameter is gradually enlarged. And a photonic crystal fiber in which a mode field diameter is relatively larger than a mode field diameter of the single mode fiber, Wherein the outer diameter of the photonic crystal fiber has a diameter substantially the same as the ferrule constituting the optical connector. The optical fiber component of claim 2 or 5, wherein the collimated lens is a graded index fiber. The optical fiber component according to claim 6, wherein a cross section of the glade index fiber is fused to the other surface of the photonic crystal fiber. The optical fiber component according to any one of claims 4 to 7, wherein a connector housing is attached to a tip end of the photonic crystal fiber. The optical fiber component according to any one of claims 1 to 8, wherein the mode field diameter of the photonic crystal fiber is at least 20 µm.