JP2000292644A - Optical module and optical wavelength monitoring method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact optical module decreasing a time required for an operation by extracting signal light with multiple wavelengths simultaneously with a simple structure. SOLUTION: An optical module 7 has a lens 9 as a collimator. A planer transparent board 10 is placed in the downstream of the lens 9 in the traveling direction of multiple wavelength signal light L. A planer surface of the transparent board 10 is placed vertical to the light axis of the multiple wavelength signal light L converted into parallel light through the lens 9. Interference filters 11a, 11b, 11c, 11d are fixed on the transparent board 10. Filter tips with different passing wavelengths are adopted to the interference filters 11a to 11d. Light receiving elements 13a to 13d are fixed in positions opposing to the individual interference filters 11a to 11d.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical module for processing signal light in an optical communication system such as an optical transmitter, an optical receiver, an optical repeater, an optical node, and an optical switch. The present invention relates to an optical module that extracts a plurality of signal lights having a desired wavelength from signal light. Further, the present invention relates to an optical wavelength monitoring method using the optical module.

[0002]

2. Description of the Related Art Conventionally, as this type of optical module,
A technique is known in which a multi-wavelength signal light emitted from an optical fiber is converted into a parallel light beam by a collimator and then passed through one interference filter to extract only one signal light having a desired wavelength. In such a technique, when extracting signal light of a plurality of wavelengths from multi-wavelength signal light, the angle of incidence of the signal light on the interference film filter is changed by rotating the interference filter, and the light passes through the interference filter. The operation of matching the wavelength of the signal light with the wavelength of the signal light to be extracted is repeatedly performed to sequentially extract the desired wavelength one by one a plurality of times.

However, in such a technique, in order to extract signal light of a plurality of wavelengths, the operation of rotating the interference filter must be repeated a number of times corresponding to the number of wavelengths to be extracted. Therefore, it took a long time to extract the signal light. Further, in a device using such a technology, since a mechanically movable portion for rotating the interference filter is provided, the number of components constituting the device increases, and the device becomes complicated and cost increases. It was connected.

As a technique for solving such a problem, a technique described in Japanese Patent Application Laid-Open No. 9-64819 is known. In the technique described in this publication, a multi-wavelength signal light emitted from an optical fiber is converted into a parallel light beam by a lens and supplied to a reflection type diffraction grating. The signal light reflected by the diffraction grating is separated for each of a plurality of wavelengths. The split multi-wavelength signal light is converged by a converging lens and is incident on a light receiving element array.

[0005] According to such a technique, signal light of a plurality of wavelengths is collectively extracted, so that it is possible to reduce the time required for signal light extraction work. Further, in a device using such a technique, it is not necessary to provide a mechanically movable part, so that the number of components constituting the device can be reduced, and the simplification of the device and cost reduction are also improved. .

[0006]

However, in the technique described in Japanese Patent Application Laid-Open No. 9-64819, an optical path is ensured so that light incident on the diffraction grating and light reflected from the diffraction grating do not overlap. Must-have. For this reason, there is a limit in miniaturization of the apparatus. In addition, the diffraction grating has a high temperature dependency, and the reproducibility and reliability of data may be reduced due to the temperature fluctuation of the outside air.Therefore, it is necessary to perform temperature compensation on the diffraction grating to prevent this problem. Was. Further, the diffraction grating has to produce fine irregularities on its surface regularly, which has a problem that a manufacturing process for obtaining a diffraction grating with high performance is difficult.

[0007]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems with the following characteristic configuration in an optical module and an optical communication system using the optical module.

That is, an optical module according to the present invention has a collimator for converting multi-wavelength signal light incident from an optical transmission line into parallel light beams, and a plurality of optical filters having different passing wavelengths. By passing the light through a filter, a demultiplexing unit for demultiplexing the parallel light beam into a plurality of light beams having different wavelengths, and a light receiving unit for receiving the signal light of each wavelength demultiplexed by the demultiplexing unit are provided. I do.

[0009]

Embodiments of the present invention will now be described with reference to the drawings.

(First Embodiment) First, a first embodiment of the present invention will be described.
The embodiment will be described with reference to FIGS. 1 and 2. FIG. FIG. 1 is a configuration diagram of an optical module showing a first embodiment of the present invention. FIG. 1 (a) is an overall configuration diagram of the optical module, and FIG. 1 (b) is an arrow in FIG. 1 (a). FIG. 1C is a diagram viewed from the direction of the arrow IB, and FIG. 1C is a diagram of FIG. 1A viewed from the direction of the arrow IC. FIG. 2 is an explanatory diagram of an optical communication system using the optical module according to the embodiment.

The optical communication system 1 shown in FIG.
This is a system for monitoring each wavelength multiplexed on the multi-wavelength signal light in a system for transmitting the multi-wavelength signal light.

In FIG. 2, an optical communication system 1 is provided with an optical fiber 2 as an optical transmission path. The multi-wavelength signal light L is transmitted to the optical fiber 2. In the multi-wavelength signal light L, signal lights of a plurality of wavelengths λi (i = 1, 2, 3,...) Are multiplexed. In this embodiment, a multi-wavelength signal light L in which four wavelengths λi (i = 1 to 4) are multiplexed.
The case where is used will be described.

A coupler 3 is connected to the optical fiber 2. One of the multi-wavelength signal lights L branched by the coupler 3 is output as it is to the downstream side, and the other is output to the optical fiber 4 as an optical transmission line. At the other end of the optical fiber 4,
The optical monitor 6 is connected. The optical monitor 6 has an optical module 7 and a signal processing circuit 8.

In FIG. 1A, an optical module 7 is
It has a circular lens 9 as a collimator. The lens 9 is arranged so that its focal position coincides with the position of the end face of the optical fiber 4. In the present embodiment, the end face of the optical fiber 4 is subjected to a non-reflection coating process, and the reflected return light of the multi-wavelength signal light L itself emitted from the end face of the optical fiber 4 enters the end face of the optical fiber 4. Has been prevented. It is also possible to perform an oblique polishing process on the end face of the optical fiber 4 to prevent the reflected return light from being incident on the end face of the optical fiber 4.

A flat transparent plate 10 is disposed downstream of the lens 9 in the traveling direction of the multi-wavelength signal light L. The transparent plate 10 is made of a glass material.
The plane is formed in a rectangular shape as shown in FIG. The transparent plate 10 is arranged so that its plane is perpendicular to the direction of the optical axis A of the multi-wavelength signal light L converted into parallel light by the lens 9. In the present embodiment, the optical axis A coincides with the center position of the circular lens 9.

As shown in FIG. 1B, a plane 10a of the transparent plate 10 has interference filters 11a, 11b, 11c, 1c.
1d is fixed at regular intervals. The interference filters 11a to 11d employ filter chips having different passing wavelengths. In the first embodiment,
As the interference filters 11a to 11d, four types of filter chips whose passing wavelengths correspond to the respective wavelengths λ1 to λ4 of the multi-wavelength signal light L are employed. Interference filter 1
1a to 11d constitute the spectral unit of the present embodiment.

A fixed plate 12 is disposed downstream of the transparent plate 10 in the traveling direction of the multi-wavelength signal light L. This fixing plate 12
Are arranged such that the plane thereof is parallel to the plane of the transparent plate 10. As shown in FIG.
The light receiving elements 13a to 13d are fixed to the plane 12a at positions corresponding to the interference filters 11a to 11d. These light receiving elements 13a to 13d have a function of converting received signal light into electric signals. Light receiving elements 13a to 13d
A generally used light receiving element such as a one-dimensional array type light receiving chip or a two-dimensional array type light receiving chip can be used. Further, a signal processing circuit 8 is connected to the optical module 7 as shown in FIG. The electric signals output from the light receiving elements 13a to 13d are input to the signal processing circuit 8. This signal processing circuit 8
This is a circuit that performs various processes on an input electric signal, and a generally used circuit can be employed. The light receiving elements of this embodiment are constituted by the light receiving elements 13a to 13d.

Next, the operation of the first embodiment of the present invention having the above-described configuration will be described.

In FIG. 2, the multi-wavelength signal light L transmitted through the optical fiber 2 of the optical communication system 1 is split by the coupler 3. One of the branched multi-wavelength signal lights L is output to the downstream side as it is, and the other is output to the optical fiber 4. The multi-wavelength signal light L input to the optical fiber 4 is transmitted to the optical module 7 of the optical monitor 6.

In FIG. 1A, in the optical module 7, multi-wavelength signal light L is emitted from the end face of the optical fiber 4. Multi-wavelength signal light L emitted from the end face of optical fiber 4
Is converted by the lens 9 into parallel rays. The multi-wavelength signal light L converted into a parallel light by the lens 9 is
After passing through 0, it is supplied to each of the interference filters 11a to 11d. Each of the interference filters 11a to 11d passes only the signal light having a predetermined wavelength corresponding to the wavelengths λ1 to λ4 from the multi-wavelength signal light L passing therethrough. Therefore, each interference filter 11a
The multi-wavelength signal light L that has passed through .about.11d is collectively split into signal lights L1 to L4 having wavelengths .lambda.1 to .lambda.4, respectively.

Each of the multi-wavelength signal lights L1 to L4 is
3a to 13d. Each of the light receiving elements 13a to 13d
Each of the signal lights L1 to L4 is received, and each of the signal lights L1 to L4 is received.
And outputs an electrical signal corresponding to the wavelengths λ1 to λ4. The electric signals output from the light receiving elements 13a to 13d are output to the signal processing circuit 8.

As is clear from the above description, this first
In the embodiment, the operation of extracting a plurality of wavelengths from the multi-wavelength signal light L can be collectively performed by one operation. Further, since the transparent plate 10 and the fixed plate 12 are arranged on the optical axis A of the parallel light beam converted by the lens 9, the optical path of the signal light transmitted in the device can be kept linear. For this reason, the optical path length of each signal light can be shortened, and the size of the device can be further reduced as compared with the related art.

Further, since the components constituting the apparatus employ an interference filter which is inexpensive and easy to manufacture as compared with the diffraction grating, the cost of the apparatus can be reduced.
Furthermore, since the optical module has no mechanically movable parts, the reliability of the device in terms of long-term stability and precision can be improved.

(Second Embodiment) Next, a second embodiment of the present invention will be described.
The embodiment will be described with reference to FIGS. 3 and 4. FIG.

FIG. 3 is an explanatory view of an optical module showing a second embodiment of the present invention, and FIG. 3 (a) is an overall explanatory view.
FIG. 3B is a diagram of FIG. 3A viewed from the direction of arrow IIIB, and FIG. 3C is a diagram of FIG. 3A viewed from the direction of arrow IIIC.

In the description of the second embodiment, the same components as those of the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

The second embodiment has the following advantages in the first embodiment.
Although the present embodiment is different from the first embodiment, the other points are the same as those of the first embodiment.

In the optical module 21 according to the second embodiment shown in FIG. 3, a transparent plate 22 having a square plane is disposed instead of the transparent plate 10 having a rectangular plane. The transparent plate 22 is made of a glass material like the transparent plate 10. The length of one side of the plane of the transparent plate 22 is the same as the diameter of the lens 9. Further, the transparent plate 22
Like the transparent plate 10, is arranged so that its plane is perpendicular to the optical axis A direction of the multi-wavelength signal light L converted into parallel light by the lens 9.

As shown in FIG. 3B, interference filters 11a to 11d as spectral means corresponding to wavelengths λ1 to λ4 are arranged on a plane 22a of the transparent plate 22. Each of the interference filters 11a to 11d is arranged on a circumference having a radius d (mm) around the optical axis A described above.

The optical module 21 of the present embodiment is similar to that of FIG.
(C) As shown in FIG.
, A fixed plate 23 having a square plane similar to the transparent plate 22 is arranged. The fixing plate 23 is arranged so that its plane is parallel to the plane of the transparent plate 22. As shown in FIG. 3C, light receiving elements 13a to 13d as light receiving means are fixed to the plane 23a of the fixed plate 23 at positions corresponding to the respective interference filters 11a to 11d. Light receiving element
Similarly to the interference filters 11a to 11d, the reference numerals 13a to 13d are arranged on a circumference having a radius d (mm) about the optical axis A.

Next, the operation of the second embodiment of the present invention having the above-described configuration will be described.

In FIG. 3A, the lens 9 of the optical module 21 converts the multi-wavelength signal light L emitted from the end face of the optical fiber 4 into parallel light,
The signal is supplied to each of the interference filters 11a to 11d fixed to 2a. Each of the interference filters 11a to 11d passes only the signal light having a predetermined wavelength corresponding to the wavelengths λ1 to λ4 from the multi-wavelength signal light L passing therethrough. Therefore, each interference filter 11a
The multi-wavelength signal light L that has passed through .about.11d is collectively separated into signal lights L1 to L4 having wavelengths .lambda.1 to .lambda.4, respectively.

The signal lights L1 to L4 are supplied to the light receiving elements 13a to 13d corresponding to the interference filters 11a to 11d. Each of the light receiving elements 13a to 13d is a signal light L1 to L4.
And outputs a detection signal to the signal processing circuit 8.

FIG. 4 is a graph showing the intensity of each signal light supplied to the light receiving elements 13a to 13d in the optical module of the embodiment. In FIG. 4, the horizontal axis represents the distance from the optical axis A in the vertical direction, and the vertical axis represents the intensity. As shown in FIG. 4, the intensity of the multi-wavelength signal light L converted into a parallel light beam by the lens 9 is distributed in a pseudo-Gaussian shape, and the position of the optical axis A is the strongest and the vertical direction from the position of the optical axis A. It gets weaker as you go away.
In addition, as shown in FIG.
(Mm) are at the same intensity P (dB)
become. In the present embodiment, the interference filter 11a
11d are arranged on the circumference of the radius d (mm) centered on the optical axis A by the lens 9 so that the intensities of the signal lights L1 to L4 passing through the respective interference filters 11a to 11d are all uniform. High intensity P (dB).

As is apparent from the above description, in the present embodiment, the intensity of each signal light is made uniform by making the intensity of the signal light L1 to L4 of each wavelength supplied to the light receiving elements 13a to 13d uniform. Can be reduced.

(Third Embodiment) Next, a third embodiment of the present invention will be described.
The embodiment will be described with reference to FIGS. 5 and 6. FIG.

FIG. 5 is an overall configuration diagram of an optical module according to a third embodiment of the present invention. FIG. 6 is an enlarged view of a main part of FIG. 5, and FIG. 6 (a) is a view of FIG.
FIG. 6B is a view of FIG. 5 viewed from the direction of arrow VIB.
(C) is the figure which looked at FIG. 5 from the arrow VIC direction.

In the description of the third embodiment, the same components as those of the first or second embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted. .

The third embodiment is different from the first embodiment in the following points.
Alternatively, the configuration is different from that of the second embodiment, but the configuration is otherwise the same as that of the first or second embodiment.

In this embodiment, the multi-wavelength signal light L is
A case where six wavelengths λi (i = 1 to 16) are multiplexed will be described.

In FIG. 5, the optical module 31 of the present embodiment has 16 interference filters 32a to 32d, 33a on the plane 22b of the transparent plate 22, as shown in FIG.
33h and 34a to 34d are arranged. These interference filters 32a to 32d, 33a to 33h, 34a to 34d
Employs filter chips having different passing wavelengths, and the passing wavelength of each interference filter is the wavelength λ.
1 to λ16.

As shown in FIG. 6A, the interference filter 3
2a to 32d are arranged on the circumference of a circle C1 having a radius d1 (mm) centered on the optical axis A. In addition, the interference filter 3
3a to 33h are radii d2 (mm) about the optical axis A.
(D2> d1) are arranged on the circumference of the circle C2. The interference filters 34a to 34d are arranged on the circumference of a circle C3 having a radius d3 (mm) (d3> d2) around the optical axis A. Interference filters 32a to 32d, 33a to 33
h, 34a to 34d constitute the demultiplexing means of the present embodiment.

As shown in FIG. 6B, on the plane 22a of the transparent plate 22, attenuation filters 36a to 36d and 37a to 37d are provided.
h is arranged corresponding to the interference filters 32a to 32d and 33a to 33h. As the attenuation filters 36a to 36d, ND filters having the same transmittance are used. Also, ND filters having the same transmittance are used for the attenuation filters 33a to 33h. Attenuation filter 32a ~
32d and the attenuation filters 33a to 33h attenuate the intensity of each of the signal lights L1 to L4 and L5 to L12 that have passed through the interference filters 32a to 32d and 33a to 33h, and the signal lights that have passed through the interference filters 34a to 34d. L1
It is used for the purpose of equalizing the strength of 3 to L16.

Each of these attenuation filters 32a to 32d, 33
For a to 33h, attenuating filters having various transmittances can be adopted at the stage of designing the optical module. In the present embodiment, ND filters are employed as these attenuation filters, but other filters generally known as pass-type attenuation filters can be employed. The attenuation means of the present invention is constituted by the attenuation filters 36a to 36d and 37a to 37h.

In FIG. 6C, the plane 2 of the fixing plate 23
3a includes interference filters 32a to 32d and 33a to 33
h, light receiving elements 41a to 41a at positions corresponding to 34a to 34d.
d, 42a to 42h and 43a to 43d are fixed. These light receiving elements 41a-41d, 42a-42h, 43a-
43d denotes interference filters 32a to 32d, 33a to 33h,
Similarly to 34a to 34d, they are arranged on the circumferences of circles C1, C2 and C3. Light receiving elements 41a to 41d, 42
Light receiving means of the present embodiment is constituted by a to 42h and 43a to 43d.

Next, the operation of the third embodiment of the present invention having the above-described configuration will be described.

In FIG. 5, the lens 9 of the optical module 31 converts the multi-wavelength signal light L emitted from the end face of the optical fiber 4 into a parallel light beam, and converts the multi-wavelength signal light L into a parallel light beam. 32a-32d, 33a-33
h, 34a to 34d. Each interference filter 32a-3
The 2d, 33a to 33h, and 34a to 34d allow only the signal light of a predetermined wavelength corresponding to the wavelengths λ1 to λ16 of the passing multi-wavelength signal light L to pass. Therefore, the multi-wavelength signal light L that has passed through each of the interference filters 32a to 32d, 33a to 33h, and 34a to 34d is collectively split into signal lights L1 to L16 having wavelengths λ1 to λ16, respectively.

FIG. 7 is a graph showing the intensity of each signal light output from the demultiplexing means in the optical module of the embodiment. In FIG. 7, the horizontal axis represents the distance from the optical axis A in the vertical direction, and the vertical axis represents the intensity.

As shown in FIG. 7, each interference filter 3
The intensity of each signal light L1 to L16 output by 2a to 32d, 33a to 33h, and 34a to 34d depends on the signal light output by the interference filters 32a to 32d arranged on the circumference of the circle C1 having a radius d1 (mm). The intensity P1 of L1 to L4 is the strongest and the radius d2
(Mm) interference filter 33a arranged on the circumference of the circle C2
To the intensity P2 of the signal light L5 to L12 output by
In the order of the intensities P3 of the signal lights L13 to L16 output by the interference filters 34a to 34d arranged on the circumference of the circle C3 having a radius d3 (mm), the signal light L13 to L16 follow a pseudo Gaussian distribution as the distance from the optical axis A increases. Strength is weak.

In FIG. 5, each of the interference filters 32a-3
The respective signal lights L1 to L16 output by 2d, 33a to 33h and 34a to 34d pass through the transparent plate 22, and the signal lights L1 to L4 are supplied to attenuation filters 36a to 36d.
The signal lights L5 to L12 are supplied to attenuation filters 37a to 37h.

FIG. 8 is a graph showing the intensity of each signal light output from the attenuating means in the optical module of the embodiment. 8, the horizontal axis indicates the distance from the optical axis A in the vertical direction, and the vertical axis indicates the intensity.

As shown in FIG. 8, the signal lights L1 to L4 having the intensity P1 pass through the attenuation filters 36a to 36d, so that the intensity is attenuated and the signal lights L'1 to L3 having the intensity P3 are reduced.
Converted to L'4. Similarly, the signal light L5 to L1 having the intensity P2
2 also passes through the attenuating filters 37a to 37h, so that its intensity is attenuated and the signal light L'5 to L 'having the intensity P3
Converted to 12. The signal lights L13 to L16 having the intensity P3 travel downstream while maintaining the intensity P3. Therefore, in the present embodiment, each of the attenuation filters 36a to 36d, 3
The intensity of each signal light L1 to L16 can be made uniform by 7a to 37h.

Light receiving elements 41a-41d, 42a-42h, 4
3a to 43h are the signal lights L'1 to L 'which are made uniform to the intensity P3.
'12, L13 to L16, and outputs a detection signal to the signal processing circuit 8.

As is apparent from the above description, in the present embodiment, the signal wavelengths L1 to L16 of the respective wavelengths to be extracted from the multi-wavelength signal light L are kept in a uniform state while maintaining the intensity of the extracted wavelengths. The number can be increased.

(Fourth Embodiment) Next, a fourth embodiment of the present invention will be described.
The embodiment will be described with reference to FIG.

FIG. 9 is an explanatory view of an optical module according to a fourth embodiment of the present invention. FIG. 9A is an overall explanatory view, and FIG.
FIG. 9B is a diagram of FIG. 9A viewed from the direction of arrow IXB.

In the description of the fourth embodiment, the same components as those of the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

The fourth embodiment is different from the first embodiment in the following points.
Although the present embodiment is different from the first embodiment, the other points are the same as those of the first embodiment.

In FIG. 9A, the optical module 51 according to the fourth embodiment does not have the transparent plate 10 shown in FIG. 2 and the interference filters 11a to 11d are fixed to the light receiving elements 13a to 13d. The interference filters 11a to 11d are fixed by depositing the interference filters 11a to 11d on the light receiving elements 13a to 13d.

As is clear from the above description, according to the present embodiment, the number of parts constituting the apparatus can be further reduced, and the cost can be reduced or the apparatus can be downsized.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above embodiments, and without departing from the present invention described in the claims. Various design changes can be made. Modification examples of the embodiment of the present invention will be exemplified below.

(1) In each embodiment, the number of wavelengths to be extracted is limited to four. However, the number of wavelengths to be extracted can be changed. In this case, the transparent plates 10 and 2
2, the number of interference filters fixed to 2 is increased or decreased in accordance with the number of wavelengths to be extracted,
This is possible by increasing or decreasing the number of light receiving elements.

(2) In each embodiment, the transparent plate 1
It is also possible to incline the surfaces 10a and 22a of 0 and 22 and the surfaces 12a and 23a of the fixed plates 12 and 23 from a direction perpendicular to the optical axis of the multi-wavelength signal light L converted into parallel light by the lens 9. In this case, the interference filters 11a to 11a
1d and the light receiving surfaces of the light receiving elements 13a to 13d are inclined from the above-described vertical direction, so that the interference filters 11a to 11d
Alternatively, it is possible to prevent the reflected light from the light receiving elements 13a to 13d from returning to the end face of the optical fiber 4.

(3) In the fourth embodiment, the arrangement of the interference filters 11a to 11d and the light receiving elements 13a to 13d is the same as that of the first embodiment. However, as in the third embodiment, the arrangement is concentric. It is also possible to arrange on the circumference.

(4) In the first or fourth embodiment, the light receiving elements 13a to 13d are provided in the signal processing circuit 8 based on the light intensities of the signal lights L1 to L4.
It is possible to provide a function of correcting the magnitude of the electric signal output from the device to be uniform. As a circuit having such a function, a circuit generally used conventionally can be adopted.

[0066]

As described above, according to the present invention, the collimator converts the multi-wavelength signal light incident from the optical transmission line into parallel light beams, and the plurality of optical filters of the demultiplexing means convert the parallel light beams into wavelengths. At a time, and the light receiving means receives the signal light of each wavelength demultiplexed by the demultiplexing means, so that the signal light of multiple wavelengths is collectively extracted from the multi-wavelength signal light. In addition, the time required for the extraction operation can be reduced. Further, since the optical module of the present invention extracts a plurality of wavelengths using a plurality of optical filters, there is no need to provide a mechanically movable portion, the number of components constituting the device can be reduced, and the device can be simplified. Therefore, cost reduction and downsizing of the device can be realized.

Further, in the optical module of the present invention, when the plurality of optical filters are interference filters, the cost can be further reduced because the interference filters are inexpensive and easy to manufacture.

[Brief description of the drawings]

FIGS. 1A and 1B are configuration diagrams of an optical module according to a first embodiment of the present invention. FIG. 1A is an overall configuration diagram of the optical module, and FIG. FIG. 1C is a diagram viewed from the direction of the arrow IB, and FIG. 1C is a diagram of FIG. 1A viewed from the direction of the arrow IC.

FIG. 2 is an explanatory diagram of an optical communication system using the optical module according to the first embodiment of the present invention.

3A and 3B are explanatory views of an optical module according to a second embodiment of the present invention. FIG. 3A is an overall explanatory view, and FIG. 3B is a view of FIG. 3A viewed from the direction of arrow IIIB. FIG. 3 (c)
FIG. 3A is a view of FIG. 3A viewed from the direction of arrow IIIC.

FIG. 4 is a graph showing the intensity of each signal light supplied to a light receiving unit in the optical module according to the second embodiment of the present invention.

FIG. 5 is an overall configuration diagram of an optical module according to a third embodiment of the present invention.

FIG. 6 is an enlarged view of a main part of FIG. 5, and FIG.
6 (b) is a view of FIG. 5 viewed from the direction of arrow VIB, and FIG. 6 (c) is a view of FIG. 5 viewed from the direction of arrow VIC.

FIG. 7 is a graph showing the intensity of each signal light output from the demultiplexing unit in the optical module according to the third embodiment of the present invention.

FIG. 8 is a graph showing the intensity of each signal light output by the attenuating means in the optical module according to the third embodiment of the present invention.

FIG. 9 is an explanatory diagram of an optical module according to a fourth embodiment of the present invention. FIG. 9A is an overall explanatory diagram, and FIG.
FIG. 9B is a diagram of FIG. 9A viewed from the direction of arrow IXB.

[Explanation of symbols]

A: optical axis, L: multi-wavelength signal light. 1. Optical communication system,
(7, 21, 31, 51): optical module, 9: lens, (10, 22): transparent plate, (11a to 11d, 32a)
~ 32d, 33a ~ 33h, 34a ~ 34d) ... interference filter, (12, 23) ... fixed plate, (36a ~ 36, 37a ~)
37h) ... Attenuation filter, (13a-13d, 41a-41)
d, 42a to 42h, 43a to 43d) ... light receiving element.

Claims (9)

[Claims] 1. A collimator for converting multi-wavelength signal light emitted from an optical transmission line into parallel light beams, and a plurality of optical filters having different passing wavelengths, wherein the parallel light beams pass through the plurality of optical filters. And a light receiving unit that receives the signal light of each wavelength that has been split by the splitting unit. Optical module. 2. The optical module according to claim 1, wherein
The optical module according to claim 1, wherein the demultiplexing means is arranged such that each optical axis direction of the plurality of signal lights having different wavelengths coincides with an optical axis direction of the parallel light beam. 3. The optical module according to claim 1, wherein
An optical module, further comprising an attenuating means for attenuating each intensity of the plurality of signal lights having different wavelengths received by the light receiving means to a minimum intensity of the plurality of signal lights. 4. The optical module according to claim 1, wherein
An optical module, wherein the light receiving means has a plurality of light receiving elements corresponding to the plurality of optical filters. 5. The optical module according to claim 1, wherein
The optical module according to claim 1, wherein the plurality of optical filters are arranged on at least one or more concentric circles centered on an optical axis of the parallel light beam and orthogonal to the optical axis. 6. The optical module according to claim 1, wherein
An optical module, wherein the plurality of optical filters are arranged such that the intensities of the parallel light beams passing therethrough are uniform. 7. The optical module according to claim 1, wherein
The optical module, wherein the plurality of optical filters are interference filters. 8. The optical module according to claim 1, wherein
An optical module, wherein each of the plurality of optical filters and the light receiving means has a light receiving surface inclined with respect to an end surface of the optical transmission path. 9. A multi-wavelength signal light emitted from an optical transmission line is converted into a parallel light beam, and the parallel light beam is passed through a plurality of optical filters having different passing wavelengths, thereby converting the parallel light beam into a plurality of signals having different wavelengths. An optical wavelength monitoring method, comprising demultiplexing light into light and receiving each of the plurality of signal lights.