JPH0749467A - Optical coupling part - Google Patents

Abstract

PURPOSE:To provide an optical coupling part which can be downsized and stabilize the performance. CONSTITUTION:A garnet crystal 6 for rotating a polarizing surface by 22.5 deg., a filter for reflecting a light having a wavelength of lambda and transmitting a light having a wavelength of lambda2, a garnet crystal 9 for rotating the polarizing surface at 45 deg., and a reflecting plate 10 are provided in this order on one end of a focusing rod lens 5, and a rutile crystal 3 and two optical fibers 1, 2 are provided on the other end. A 1/2 wavelength plate 4 is provided between the focusing rod lens 5 and the rutile crystal 3 to cover the half of the lens 5, and four functions in total of wavelength selecting function, wavelength combining function, and two optical isolators having opposed directions are realized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical coupling component used for wavelength division multiplex communication using an optical fiber amplifier.

[0002]

2. Description of the Related Art Conventionally, when one optical fiber amplifier is used for wavelength division multiplexing bidirectional transmission, each optical component is connected as shown in FIG. In FIG. 5, 51 is a pump laser for generating light having a wavelength of 1.48 μm, 52 is a wavelength coupler, 53 is an erbium-doped erbium-doped optical fiber, 54, 57, 60 and 63 are wavelength couplers, 55 and 56. , 61 and 62 are optical isolators that pass light in only one direction, and 58, 59, 64 and 65 are optical fibers.

Now, the light having a wavelength of 1.48 μm output from the pump laser 51 is input to the erbium-doped optical fiber 53 by the wavelength coupler 52 to activate the erbium ion. On the other hand, the wavelength 1.
The 53 .mu.m (.lambda.1) signal light is wavelength-selected by the wavelength coupler 54 and passes through the optical isolator 55.
The wavelengths are combined in 7 and merged into the optical fiber 59. The light of wavelength 1.53 μm (λ 1) that has entered the erbium-doped optical fiber 53 through the wavelength coupler 52 is amplified there, wavelength-selected by the wavelength coupler 60, enters the optical isolator 61, and is wavelength-combined by the wavelength coupler 63. It is merged with the optical fiber 65 and output.

On the other hand, the wavelength 1.
The 55 μm (λ 2) signal light is wavelength-selected by the wavelength coupler 63, passes through the optical isolator 62, is wavelength-combined by the wavelength coupler 60, and enters the optical fiber 64. Light having a wavelength of 1.55 μm (λ 2) enters the erbium-doped optical fiber 53, is amplified, and enters the optical fiber 59 via the wavelength coupler 52. Next, after the wavelength is selected by the wavelength coupler 57 and passed through the optical isolator 56, the wavelength coupler 5
The wavelengths are combined in 4 and output from the optical fiber 58.

As described above, the signal lights having the wavelengths of 1.53 μm (λ1) and 1.55 μm (λ2) are transmitted in the opposite directions by using the wavelength coupler and the isolator. Since the light of the wavelength does not return in the opposite direction by the optical isolator, each light independently constitutes an optical fiber amplifier.

[0006]

However, as described above, the two components constituted by fiber-connecting the four single-function optical components consisting of the two wavelength couplers and the two optical isolators are used. The mounting area becomes large, which makes the optical fiber amplifier large. Further, since the insertion loss changes depending on how each component is connected or when the optical fiber is housed, there is a problem in that the characteristic varies depending on the configuration of the optical fiber amplifier and the performance is not stable.

The present invention has been made in view of the above problems of the conventional optical fiber amplifier, and an object thereof is to provide an optical coupling component which can be downsized and whose performance can be stabilized. .

[0008]

According to the present invention of claim 1, there are provided two optical fibers for inputting or outputting light, and part 2 thereof.
And a birefringent means which is provided close to each of the two optical fibers and separates the light incident from one of the optical fibers into two orthogonal linearly polarized light, and a birefringent means which is provided near the birefringent means and is separated. And a polarization means for changing the polarization plane of each polarization, the polarization means rotates the light of a predetermined wavelength λ1 which is input from one optical fiber and is birefringent by a predetermined angle α, but is input from the other optical fiber. The optical coupling component is rotated by a predetermined angle β which is different from the predetermined angle α and is birefringent.

According to a third aspect of the present invention, an optical fiber for entering or emitting light, a birefringent plate provided in the vicinity of the optical fiber, and the birefringent plate on the opposite side of the optical fiber. A lens for converging light, a first polarization plane rotation plate provided on the side opposite to the birefringence plate of the lens for rotating the polarization plane of the light by a predetermined angle γ, and the first polarization plane rotation plate. A filter provided on the opposite side of the lens for reflecting the light of the first wavelength λ1 and transmitting the light of the second wavelength λ2;
A second polarization plane rotation plate, which is provided on the opposite side of the filter from the first polarization plane rotation plate and rotates the polarization plane of light by a predetermined angle δ, and is provided on the opposite side of the second polarization plane rotation plate from the filter. Is provided between the birefringence plate and the lens so as to cover a predetermined partial area of the surface of the birefringence plate and the reflection plate that reflects light, and the polarization plane of the passing light is rotated by a predetermined angle ε. Third to let
An optical coupling component including a polarization plane rotating plate.

[0010]

According to the present invention, the birefringence means separates the light having the predetermined wavelength λ1 inputted from one optical fiber into two linearly polarized lights which are orthogonal to each other, and the polarizing means separates the respective separated linearly polarized lights at a predetermined angle α. Although rotated, the light input from the other optical fiber and split into two orthogonal linearly polarized lights is rotated by a predetermined angle β different from the predetermined angle α.

Further, according to the present invention, the light of wavelength λ1 incident from the optical fiber is separated into two orthogonal linearly polarized lights by the birefringent plate and is reflected by the filter, whereby the first polarization plane rotating plate is used. The polarization plane is rotated by a predetermined angle γ, and the polarization plane is rotated by a predetermined angle ε by the third polarization rotation plate.
The light of wavelength λ2 incident from the optical fiber is separated into two orthogonal linearly polarized lights by the birefringence plate, transmitted through the filter and reflected by the reflection plate, so that the polarization plane is changed by the first polarization plane rotation plate. The polarization plane is rotated by a predetermined angle γ, the polarization plane is rotated by a predetermined angle δ by the second polarization plane rotation plate, and the polarization plane is rotated by a predetermined angle ε by the third polarization plane rotation plate.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings showing its embodiments.

FIG. 1A is a diagram showing the configuration of an optical coupling component according to the first embodiment of the present invention. Also, FIG. 1 (a)
2A and 2B are diagrams showing the behavior of light having a wavelength of 1.53 μm (λ1), and FIGS. 2A and 2B are
It is a figure which shows the behavior of the light of wavelength 1.55 micrometer ((lambda) 2).

In FIG. 1 (a), 1 and 2 are optical fibers for inputting and outputting light, 3 is a rutile crystal having a birefringence function, and 4 is a third polarization plane rotating plate for rotating light by 45 degrees. / 2 wavelength plate (rotation direction varies depending on the incident direction of light), 5 is a converging rod lens, 6 is a garnet crystal as a first polarization plane rotation plate that rotates a polarization plane by 22.5 degrees by magnetism, 7 is glass A plate, 8 is a filter that reflects light with a wavelength of 1.53 μm and transmits light with a wavelength of 1.55 μm, 9 is a garnet crystal as a second polarization plane rotation plate that rotates the polarization plane by 45 degrees by magnetism, and 10 is light Is a reflection plate for reflecting the light, 11 is a magnet for giving a magnetic field to the garnet crystals 6, 9, 12 is incident light, 13 is outgoing light, 14 to 21 and 24 to 31 are optical paths, and arrows described on the optical path side are The direction of the plane of polarization is shown. Further, the half-wave plate 4, the converging rod lens 5, the garnet crystals 6 and 9, the glass plate 7, the filter 8 and the reflecting plate 10 constitute a polarizing means.

Next, the operation of the optical coupling component of the first embodiment will be described with reference to the drawings.

First, as shown in FIG. 1A, light having a wavelength of 1.53 μm (first wavelength λ) is incident from the optical fiber 1.
1) is split into two linearly polarized light beams orthogonal to each other by the rutile crystal 3 and enters the garnet crystal 6 through the optical paths 14 and 15 in the converging rod lens 5, respectively. Here, the glass plate 7 having a thickness of 0.9 mm is used as an adjusting spacer for optimizing the reflection position. The light incident on the garnet crystal 6 passes through the glass plate 7 and is then reflected by the filter 8 along the optical paths 16 and 17.
Therefore, the plane of polarization of the light that has entered the garnet crystal 6, is reflected by the filter 8 and has been transmitted through the garnet crystal 6 twice is rotated 45 degrees counterclockwise. Then, the light passing through the optical paths 16 and 17 has its plane of polarization further rotated counterclockwise by 45 degrees by the half-wave plate 4 and is rotated by 90 degrees in total, so that the two orthogonal light beams are obtained.
The two polarized lights are polarized and combined by the rutile crystal 3 and enter the optical fiber 2 to be output as the light 13.

On the other hand, as shown in FIG. 1B, the light 12 having a wavelength of 1.53 μm incident from the optical fiber 2 is polarized and separated by the rutile crystal 3 and then polarized by the ½ wavelength plate 4. It is rotated 45 degrees clockwise. Next, a wavelength of 1.53 traveling along the optical paths 18 and 19 in the converging rod lens 5.
The light of μm is transmitted through the garnet crystal 6 twice before and after being reflected by the filter 8 and the polarization plane of the light is rotated 45 degrees counterclockwise as before. As a result, garnet crystals 6 and 1
The polarization plane of the light transmitted through the / 2 wavelength plate 4 does not rotate. After that, the light reflected by the filter 8 has an optical path 20,
Proceed through 21, and enter the rutile crystal 3. Since the light incident on the rutile crystal 3 is not polarized and combined, it is not coupled to the optical fiber 1. Therefore, the light having the wavelength of 1.53 μm is transmitted only from the optical fiber 1 to the optical fiber 2.

Next, as shown in FIG. 2A, light having a wavelength of 1.55 μm (second wavelength λ) is incident from the optical fiber 2.
2) is polarized and separated by the rutile crystal 3, and each polarized light is rotated 45 degrees clockwise by the ½ wavelength plate 4,
The light passes through the focusing rod lens 5 along optical paths 24 and 25, respectively. At this time, the filter 8 has a wavelength of 1.55 μm
Since each of the polarized lights is transmitted, the polarized planes of the polarized lights are counterclockwise by the garnet crystal 6 and the garnet crystal 9, respectively.
It is rotated by 2.5 degrees and 45 degrees. Therefore, the light having the wavelength of 1.55 μm reflected by the reflector 10 is rotated counterclockwise by 135 degrees when passing through the garnet crystal 6 and the garnet crystal 9 twice. As a result, the polarization plane of the light transmitted through the half-wave plate 4 once and transmitted through the garnet crystal 6 and the garnet crystal 9 twice is rotated by 90 degrees. After that, the light reflected by the reflecting plate 10 enters the rutile crystal 3 through the optical paths 26 and 27. The lights incident on the rutile crystal 3 are polarized and combined, and are combined with the optical fiber 1 to be output as light 23.

On the other hand, as shown in FIG. 2B, the light having a wavelength of 1.55 μm incident from the optical fiber 1 is polarized and separated by the rutile crystal 3, and then is passed through the focusing rod lens 5 in the optical path 28. Proceeding along 29, the light passes through the garnet crystal 6, the glass plate 7, the filter 8, and the garnet crystal 9. The light transmitted through the garnet crystal 6 and the garnet crystal 9 twice before and after being reflected by the reflection plate 10 has a polarization plane of 135 degrees counterclockwise.
Is rotated once. The light reflected by the reflector 10 has an optical path 30,
After going through 31, the polarization plane is rotated 45 degrees counterclockwise when passing through the half-wave plate 4, and as a result, the rotation of the polarization plane becomes a total of 180 degrees, which is the same as the case where the polarization direction is not rotated. Become. Therefore, the light incident on the rutile crystal 3 is not polarized and combined, and does not enter the optical fiber 2. Thus, the light having the wavelength of 1.55 μm is transmitted only from the optical fiber 2 to the optical fiber 1.

As described above, the light having the wavelength of 1.53 μm is transmitted from the optical fiber 1 to the optical fiber 2, and the light having the wavelength of 1.55 μm is transmitted from the optical fiber 2 to the optical fiber 1. , Light of each wavelength is not transmitted in the opposite direction. In this way, the wavelength demultiplexing / merging function and the two optical isolators that transmit lights of different wavelengths only in opposite directions are configured by using one lens, so one optical coupling component has four functions. Can be realized. Further, since the optical coupling is performed using one lens, there is an effect that the number of parts can be reduced and the size can be reduced.

FIG. 3 is a block diagram of an optical coupling component of the second embodiment according to the present invention. In FIG. 3, 32 to 34 are optical fibers, 35 is a cut filter, 36 to 38 are optical paths, and the reflection plate 10 is provided at a predetermined angle with respect to a plane perpendicular to the optical axis of the lens 5. Others are the same as those of the first embodiment of the present invention. Here, the cut filter 35 provided on the optical fiber 32 side has a characteristic of transmitting light having a wavelength of 1.53 μm and blocking light having a wavelength of 1.55 μm.

Next, the operation of the optical coupling component of the second embodiment will be described.

First, the light having a wavelength of 1.53 μm emitted from the optical fiber 32 is polarized and separated (not shown) by the rutile crystal 3, then passes through the cut filter 35, and enters the focusing rod lens 5. It passes through the optical path 36. Each polarized light is reflected by the filter 8 and is reflected by the garnet crystal 6 and the glass plate 7.
After passing through the optical path 37, it is incident on the half-wave plate 4. Therefore, the plane of polarization is rotated counterclockwise by 90 degrees by the garnet crystal 6 and the half-wave plate, and the lights incident on the rutile crystal 3 are polarized and combined and coupled to the optical fiber 34. On the other hand, as in the case of the first embodiment, since the light of wavelength 1.53 μm is not transmitted from the optical fiber 34 to the optical fiber 32, an optical isolator for coupling the optical fiber 32 to the optical fiber 34 is constructed.

Next, from the optical fiber 34, the rutile crystal 3,
Light having a wavelength of 1.55 μm that has entered the half-wave plate 4 and the converging rod lens 5 passes through the optical path 37 and is reflected by the reflection plate 10 to form the garnet crystal 6, the glass plate 7, the filter 8, and the garnet crystal 9 in two. After passing through the optical path 38, the light enters the rutile crystal 3. The path due to the reflection of the reflection plate 10 becomes the optical path 38 because the reflection plate 10 has the lens 5 as described above.
This is because it is inclined with respect to the plane perpendicular to the optical axis of. Each polarization is garnet crystal 6, garnet crystal 9, and 1 /
Since the plane of polarization is rotated 90 degrees counterclockwise by the two-wave plate, the lights incident on the rutile crystal 3 are polarized and combined to form the optical fiber 3
Combine to 3. On the other hand, as in the case of the first embodiment, since the light of wavelength 1.53 μm is not transmitted from the optical fiber 33 to the optical fiber 34, an optical isolator for coupling the optical fiber 34 to the optical fiber 33 is constructed. Further, a slight amount of the light emitted from the optical fiber 34 is reflected by the filter 8 and enters the optical fiber 32 to deteriorate the isolation. To prevent this, the cut filter 3 is used.
5 is provided.

As described above, one coupling rod lens constitutes a coupling optical system, and the coupling optical system is opposed to the optical demultiplexer in two directions.
The effect that an optical component having three functions of one optical isolator can be constructed is obtained. Furthermore, by using the cut filter, the wavelength separation characteristic can be improved.

FIG. 4 is a block diagram of an optical coupling component of a third embodiment according to the present invention. In FIG. 4, 41 and 42 are polarization-maintaining optical fibers (PMF), 43 and 44 are single mode optical fibers (SMF), and 45 is a wavelength of 1.48 μ.
m light is reflected, wavelength 1.53μm and wavelength 1.55μ
m is a filter that transmits light, 46 to 50 are optical paths,
The filter 8, the garnet crystal 9, and the reflection plate 10 are provided so as to be inclined at a predetermined angle with respect to a plane perpendicular to the optical axis of the lens 5. Others are the same as those of the first embodiment of the present invention.

Next, the operation of the optical coupling component of the third embodiment will be described.

First, the light having a wavelength of 1.48 μm emitted from the PMFs 41 and 42 is configured so as to match the ordinary light and the extraordinary light when entering the rutile crystal 3. Here, the glass plate 7 is provided to adjust the reflection position in order to optimize the coupling efficiency of the converging rod lens 5. Wavelength 1.48μ emitted from PFM41, 42
The light of m passes through the optical paths 46 and 47, is reflected by the filter 45, and then passes through the optical paths 48 and 49. The reflected light is polarized and combined by the rutile crystal 3 and coupled to the optical fiber 43 to form a polarized light combiner.

Next, the light having a wavelength of 1.53 μm emitted from the optical fiber 43 and incident on the rutile crystal 3 is polarized and separated (not shown), and then the garnet crystal 6 is separated by 2 before and after being reflected by the filter 8. By passing through the light once, the plane of polarization is rotated counterclockwise by 45 degrees and enters the ½ wavelength plate 4 through the optical path 50. Since the plane of polarization is further rotated counterclockwise by 45 ° in the half-wave plate, the lights incident on the rutile crystal 3 are polarized and combined (not shown) and coupled to the optical fiber 44. On the other hand, similarly to the first embodiment, since the light having the wavelength of 1.53 μm is not transmitted from the optical fiber 44 to the optical fiber 43, an optical isolator for coupling the optical fiber 43 to the optical fiber 44 is constructed.

Next, the light having a wavelength of 1.55 μm emitted from the optical fiber 44 and incident on the rutile crystal 3 is polarized and separated (not shown) and then transmitted through the half-wave plate 4 to have a polarization plane. Is rotated 45 degrees clockwise and enters the converging rod lens 5 to travel along the optical path 50. Each polarized light is a glass plate 7,
After passing through the filter 45, garnet crystal 6, filter 8 and garnet crystal 9, it is reflected by the reflector 10. Before and after each polarized light is reflected, the plane of polarization is rotated counterclockwise by 135 degrees by the garnet crystal 6 and the garnet crystal 9. The light reflected by the reflecting plate 10 enters the rutile crystal 3 through the optical path 49. As a result, the half-wave plate 4 is transmitted once, the garnet crystal 6 and the garnet crystal 9 are transmitted twice, the plane of polarization is rotated by 90 degrees, and the light incident on the rutile crystal 3 is polarization-combined to generate an optical fiber 43. Bind to. On the other hand, similarly to the first embodiment, since the light of wavelength 1.55 μm is not transmitted from the optical fiber 43 to the optical fiber 44,
An optical isolator that couples the optical fiber 44 to the optical fiber 43 is configured.

As described above, by adding the filter 45 and the two polarization-maintaining optical fibers 41 and 42, in addition to one wavelength coupler and two optical isolator functions having a wavelength separating / combining function, It is possible to add two wavelength synthesizing functions and a polarization synthesizing function, and it is possible to obtain an effect that an optical coupling component in which a total of six functions are integrated can be configured.

As described above, since the coupling optical system is constructed by using one lens, the optical coupling component can be made small in size and low in price, and the performance can be stabilized. Furthermore, by changing a part of the configuration, an optical coupling part having a wavelength separation function and two optical isolator functions, and six optical part functions of three wavelength coupler functions, two optical isolator functions and one polarization combining function. It is possible to obtain the effect that an optical coupling component having

In each of the above embodiments, the rutile crystal was used for the birefringent means or the birefringent plate. However, similar to the rutile crystal, if light can be separated into two linearly polarized light beams orthogonal to each other,
It may be another crystal having a birefringence function.

In each of the above embodiments, the garnet crystal is used for the first polarization plane rotation plate and the second polarization plane rotation plate, but the invention is not limited to this, and the rotation angle can be freely set.
Other materials may be used as long as they can rotate in the same direction regardless of the incident direction of light.

In each of the above embodiments, the half-wave plate is used as the third polarization plane rotation plate, but the present invention is not limited to this, and any material whose polarization plane rotates in the opposite direction depending on the incident direction of light may be used. However, another one may be used.

In each of the above embodiments, the rotation angle γ by the first polarization plane rotation plate is 22.5 degrees, the rotation angle δ by the second polarization plane rotation plate is 45 degrees, and the rotation angle by the third polarization plane rotation plate is all. Although the angle ε is set to 45 degrees, it is not limited to this as long as the rotation angle can be set so that the light can be transmitted in one direction and the light cannot be transmitted in the other direction.

In each of the above embodiments, one birefringent plate is arranged and the optical fiber is provided on the same side. However, the invention is not limited to this, and a plurality of birefringent plates may be provided at different positions. Alternatively, the traveling direction of light may be reflected or refracted to pass through the birefringent plate. Alternatively,
A birefringent plate may be provided on each of the opposing surfaces to form a transmissive structure.

[0038]

As is apparent from the above description, the present invention is provided with the polarization means for changing the polarization plane of each of the separated polarized lights, and the polarization means is birefringently inputted from one optical fiber. The light of the predetermined wavelength λ1 is rotated by a predetermined angle α, but is rotated by a predetermined angle β that is different from the predetermined angle α, which is birefringently input from the other optical fiber, so that downsizing is possible and performance is improved. It has the advantage of being stable.

[Brief description of drawings]

FIGS. 1A and 1B show a configuration of an optical coupling component according to a first embodiment of the present invention and a wavelength of 1.53 μm.
It is a figure which shows the optical coupling by the light of.

2A and 2B are diagrams showing optical coupling by light having a wavelength of 1.55 μm in the first embodiment.

FIG. 3 is a configuration diagram of an optical coupling component of a second embodiment according to the present invention.

FIG. 4 is a configuration diagram of an optical coupling component according to a third embodiment of the present invention.

FIG. 5 is a diagram showing a configuration of a conventional optical coupling component and how to use the optical coupling component in an optical fiber amplifier.

[Explanation of symbols]

 1, 2 Optical fiber 3 Rutile crystal 4 1/2 wavelength plate 5 Focusing rod lens 6 Garnet crystal that rotates the polarization plane by 22.5 degrees 7 Glass plate 8 Filter 9 Garnet crystal that rotates the polarization plane by 45 degrees 10 Reflector plate 11 Magnet 32-34 Optical fiber 35 Cut filter 41, 42 Polarization-maintaining optical fiber (PMF) 43, 44 Single-mode optical fiber (SMF) 45 Filter

Claims (6)

[Claims] 1. Two optical fibers for inputting or outputting light and two optical fibers provided in proximity to each of the two optical fibers, and light incident from one optical fiber is orthogonal to each other.
Birefringent means for separating into two linearly polarized light, and polarizing means provided in the vicinity of the birefringent means for rotating the polarization plane of each of the separated polarized lights, wherein the polarizing means is one optical fiber. The light having a predetermined wavelength λ1 which is birefringent and is rotated by a predetermined angle α is rotated by a predetermined angle β which is different from the predetermined angle α which is birefringent and is input from the other optical fiber. Optical coupling component. 2. The polarization means rotates the birefringent light having a wavelength λ2 different from the wavelength λ1 inputted from the other optical fiber by the predetermined angle α, and inputted from the one optical fiber. The optical coupling component according to claim 1, wherein the birefringent light of wavelength λ2 is rotated by the predetermined angle β. 3. An optical fiber for entering or emitting light, and a birefringent plate provided close to the optical fiber,
A lens that is arranged on the opposite side of the birefringent plate from the optical fiber and converges light, and a lens that is provided on the opposite side of the lens from the birefringent plate and rotates the plane of polarization of light by a predetermined angle γ. A polarization plane rotating plate and a filter provided on the side of the first polarization plane rotating plate opposite to the lens, which reflects light of a first wavelength λ1 and transmits light of a second wavelength λ2, and the filter. A second polarization plane rotation plate which is provided on the side opposite to the first polarization plane rotation plate and rotates the polarization plane of light by a predetermined angle δ, and the second polarization plane rotation plate which is provided on the side opposite to the filter. A reflecting plate that reflects light, and is provided between the birefringent plate and the lens so as to cover a predetermined partial area of the surface of the birefringent plate, and the polarization plane of the passing light is set at a predetermined angle. An optical coupling component comprising a third polarization plane rotating plate that rotates by ε. 4. The first polarization plane rotation plate and the second polarization plane rotation plate use magneto-optical crystals that rotate the polarization plane by magnetism, and the third polarization plane rotation plate is a half-wave plate. The optical coupling component according to claim 3, wherein 5. The number of optical fibers is three, and the reflection plate may reflect light to another optical fiber other than the optical fiber to which the light reflected by the filter is directed. The optical coupling component according to claim 3 or 4. 6. The optical coupling component according to claim 3, wherein a plurality of the filters are provided.