JP2002064431A - Optical adm equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical ADM equipment having a simple configuration. SOLUTION: An optical ADM equipment 20 has a first optical device 26, a second optical device 28, an optical amplifier 30 provided between a third port 26c of the first optical device 26 and a first port 28a of the second optical device 28, and a coupling means 32 for coupling to each other optically a fourth port 26d of the first optical device 26 and a fourth port 28d of the second optical device 28. By such an optical ADM equipment 20, the addition by a wavelength component (λi) to a wavelength multiplexing signal (λk) including a plurality of wavelength components and the dropping of a wavelength component (λj) from a wavelength multiplexing signal (λj+λk) are made possible. The added and dropped wavelength-components (λi), (λj) are amplified together with in the optical amplifier 30.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical ADM (Add Dro
p Multiplexer) device.

[0002]

2. Description of the Related Art An optical ADM apparatus extracts a drop wavelength component λi from a wavelength multiplexed signal (λ1 to λi to λj-1, λj + 1 to λn) including a plurality of wavelength components and adds an add wavelength component λj. Used for

As shown in FIG. 8, a conventional optical ADM apparatus 1 has an input 2, an output 3, a drop wavelength component output 4, an add wavelength component input 5, a pair of optical circulators 7, 12,
A pair of diffraction gratings 10, 11, a pair of optical amplifiers 8, 13,
An optical demultiplexer 9 and an optical multiplexer 14 are provided.

[0004] The optical ADM apparatus 1 operates as follows. The wavelength multiplexed signal received from the input 2 is input from the first terminal 7a of the optical circulator 7 and output to the second terminal 7b. In the output wavelength multiplexed signal, the drop wavelength component λi reflected by the diffraction grating 10 is input to the second terminal 7b and output from the third terminal 7c. Third terminal 7c
Is dropped by the optical demultiplexer 9 and output after being amplified by the optical amplifier 8.

[0005] The add wavelength component is amplified by the optical amplifier 13 after being multiplexed by the optical multiplexer 14. The amplified add wavelength component is input to the first terminal 12a of the optical circulator 12 and output to the second terminal 12b. The add wavelength component output from the second terminal 12b is reflected by the diffraction grating 11 and input to the second terminal 12b. On the other hand, the wavelength components transmitted through the diffraction gratings 10 and 11 are as follows:
The signal is input to the second terminal 12b of the optical circulator 12. These signals are output from the output 3 via the third terminal 12c of the optical circulator 12.

[0006]

The inventor has studied such an optical ADM apparatus. As a result, the light AD
The present inventors have found a problem that it is required to simplify the configuration of the M device. Considering that the optical ADM device will be further applied to WDM communication in the future, a simple configuration will not only reduce the cost but also improve the reliability.

Therefore, an object of the present invention is to provide an optical ADM apparatus having a simple configuration.

[0008]

From the viewpoint of a simple configuration, the conventional optical ADM apparatus was further studied. As a result, attention has been paid to the fact that the optical amplifiers included in the optical ADM device are provided to amplify the add wavelength component and the drop wavelength component, respectively. Thus, studies were made on reducing the number of these optical amplifiers.

As a result, the present invention has the following configuration.

An optical ADM apparatus according to the present invention comprises first and second optical devices each having first, second, third, and fourth ports, and a third port of the first optical device. An optical amplifier provided between the first optical device and the first port of the second optical device, and optically coupling the fourth port of the first optical device and the fourth port of the second optical device. And an optical coupling means.

In the first optical device, the light of the add wavelength component can be transmitted from the second port to the third port, and the light of the drop wavelength component can pass from the first port to the third port. And the light of the passing wavelength component can pass from the first port to the fourth port. In the second optical device, the add wavelength component can be transmitted from the first port to the third port, and the drop wavelength component can be transmitted to the first port.
From the fourth port to the second port, and the light of the passing wavelength component can pass from the fourth port to the third port.

Such an optical ADM apparatus is used for adding an add wavelength component to an optical signal having one or more wavelength components in a predetermined wavelength band, and for dropping a drop wavelength component from the optical signal. . For this purpose, the ADM apparatus selects an add wavelength component and a drop wavelength component by processing a wavelength component input to one of the optical devices. Both selected wavelength components are
Amplified together by the optical amplifier. In the other optical device, a drop wavelength component is selected from input wavelength components, and a pass wavelength component is output if present.

Any of the features of the present invention described below can be arbitrarily selected and combined. Even in this case, the functions and effects of the respective features can be enjoyed.

The optical coupling means is a fourth optical device.
And an optical filter between the first port and the fourth port of the first optical device. Use of an optical filter can reduce leakage of a drop wavelength component included in an input signal to an output. The optical filter can include, for example, a diffraction grating.

Each optical device of the optical ADM apparatus according to the present invention can have the following modes.

The first optical device has a first dielectric multilayer filter provided to be optically coupled to the first, third, and fourth ports. Of the light received at the first port, the light of the drop wavelength component passes through the first dielectric multilayer filter and reaches the third port, and if present, the light of the pass wavelength component is transmitted to the third port. The light is reflected by the first dielectric multilayer filter and reaches the fourth port. Also, in the first optical device, the first dielectric multilayer filter can be further optically coupled to the second port. Thus, the light of the add wavelength component received at the second port is reflected by the first dielectric multilayer filter and reaches the second port.

A second optical device includes a second optical device provided for optically coupling to the first, second, and third ports.
Has a dielectric multilayer filter. Of the light received at the first port, the light of the drop wavelength component is reflected by the second dielectric multilayer filter and reaches the second port, and the light of the add wavelength component is transmitted to the third dielectric multilayer film. The light passes through the filter and reaches the third port. In the second optical device, the second dielectric multilayer filter further includes a fourth dielectric multilayer filter.
Can be optically coupled to a port. Thus, the light of the passing wavelength component received at the fourth port is reflected by the second dielectric multilayer filter and reaches the third port.

Each optical device of the optical ADM apparatus according to the present invention may have the following configuration.

The first optical device includes first and second optical filters, and first and second optical couplers each having first to fourth terminals. In the first optical coupler, the first terminal is optically coupled to the first port, and the second terminal is optically coupled to the first terminal of the second optical coupler via the first optical filter. And a third terminal is optically coupled to a fourth terminal of the second optical coupler via a second optical filter, and the fourth terminal is optically coupled to the third port. I have. In the second optical coupler,
The second terminal is optically coupled to the second port, and the third terminal is optically coupled to the fourth port.

The second optical device includes third and fourth optical filters, and third and fourth optical couplers each having first to fourth terminals. In a third optical coupler, the first terminal is optically coupled to the second port, the second terminal is optically coupled to the fourth port,
Is optically coupled to the second terminal of the fourth optical coupler via a fourth optical filter, and the fourth terminal is connected to the first terminal of the fourth optical coupler via a third optical filter. Optically coupled to the terminal. In the fourth optical coupler, the third terminal is optically coupled to the first port, and the fourth terminal is optically coupled to the third port.

Each of the first to fourth optical filters can include, for example, a diffraction grating.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The knowledge of the present invention can be easily understood by considering the following detailed description with reference to the accompanying drawings. Hereinafter, preferred embodiments of an optical ADM device according to the present invention will be described in detail with reference to the drawings.
In the description of the drawings, the same elements will be denoted by the same reference symbols, without redundant description.

(First Embodiment) FIG. 1 shows an optical ADM apparatus 20 according to the present embodiment. Optical ADM device 20
Are signal input 20a, signal output 20b, add input 20
c, and a drop output 20d. Signal input 20
An optical waveguide 22 is coupled to a. Signal output 20
The optical waveguide 24 is coupled to b. Optical waveguide 22
The optical waveguide 24 can be formed of an optical fiber through which a wavelength multiplexed signal including a plurality of wavelength components is transmitted. The optical ADM device 20 includes a first optical device 26,
A second optical device 28, an optical amplifier 30, an optical multiplexer 34, and an optical demultiplexer 36 are provided.

The first optical device 26 has an input port 2
6a and 26b and output ports 26c and 26d. The second optical device 28 includes input ports 28a, 2
8d and output ports 28b and 28c. The optical amplifier 30 is arranged between the output port 26c and the input port 28a, and amplifies input light. Light A
The DM device 20 further includes an optical coupling unit 3 for optically coupling the output port 26d and the input port 28d.
2 is provided.

The operation of the first optical device 26 will be described below. Wavelength multiplexed signal (λj, λk) from input port 26a
Is divided into a wavelength component (λk) and a wavelength component (λj).
k) is provided to output port 26d. Also, input port 2
The wavelength component (λi) and the wavelength component (λj) from 6b are provided to output port 26c.

The operation of the second optical device 28 will be described below. The wavelength component (λj) of the wavelength component (λj) and the wavelength component (λi) from the input port 28a is provided to the output port 28b. Further, the wavelength component (λ
k) and the wavelength component (λi) are provided to output port 28c.

The wavelength component passing through the optical ADM device 20
The path of (λk) has the input port 26a and the output port 26a.
d, optical coupling means 32, input port 28d, output port 2
8c. The path of the added wavelength component (λi) is the input port 26b, the output port 26c, the optical amplifier 30, the input port 28a, and the output port 28c. The paths of the extracted wavelength component (λj) are the input port 26a, the output port 26c, the optical amplifier 30, the input port 28a, and the output port 28b. In such signal propagation, the add wavelength component (λi) and the drop wavelength component (λj) are amplified together by the optical amplifier 30.

The optical multiplexer 34 multiplexes a plurality of add wavelength components (λi) received from the add terminal 20c, and
Give to. The optical demultiplexer 36 demultiplexes the plurality of drop wavelength components (λj) from the output port 28b,
0d.

As described above, in the optical ADM apparatus according to the present embodiment, a common optical amplifier is applied to amplify the add wavelength component and the drop wavelength component.

(Second Embodiment) FIG. 2 shows an optical ADM apparatus 40 according to another embodiment. Optical ADM device 40
Then, the optical device 26 includes a dielectric multilayer filter 42.
Having. The dielectric multilayer filter 42 has a wavelength component (λ
i, λk) can be reflected and the wavelength component (λj) can be transmitted. Further, the optical device 28 has a dielectric multilayer filter 44. The dielectric multilayer filter 44 includes:
The wavelength components (λj, λk) can be reflected and the wavelength components
(λi) can be transmitted.

The light coupling means 32 may include an optical filter such as a diffraction grating 32c provided between the first and second ends 32a and 32b. The diffraction grating 36c is
The wavelength component (λj) of the wavelength multiplexed signal is reflected and the other wavelength components are transmitted. Thereby, it is possible to prevent the light of the wavelength component (λj) from leaking to the output 32b exceeding the allowable value. Further, instead of such a diffraction grating 36c, an optical waveguide (not shown) can be arranged between the first and second ends 32a and 32b. This mode is effective when the leakage of the wavelength component (λj) does not exceed the allowable value in the optical device 26.

As shown in FIG. 3A, the dielectric multilayer filters 42 and 44 include a multilayer film in which a plurality of films having different refractive indexes are alternately laminated. A dielectric multilayer filter 42,
In each of the layers 44, a layer having a thickness of λc / 4 is sequentially formed on both sides of a layer having a thickness of λc / 2 with respect to the filter center wavelength λc.

As shown in FIG. 3B, the transmission spectrum characteristic of the dielectric multilayer filter has a transmission wavelength region X centered on the wavelength λc and reflection wavelength regions Y1 and Y2 on both sides thereof.

According to FIG. 3C, the dielectric multilayer filter exhibits different filter characteristics depending on the incident angle of light.
The transmission characteristics for incident light perpendicular to the incident surface are indicated by solid lines, and the transmission characteristics for incident light whose incident angle is inclined by a predetermined angle from perpendicular are indicated by broken lines.

Referring to FIG. 3D, the filter characteristics for the reflected light are shown by broken lines. Dielectric multilayer filters are useful as transmission filters when focusing on transmitted light,
It is understood that focusing on reflected light is useful as a reflection filter.

FIGS. 4A and 4B show the transmission spectrum 42T and the reflection spectrum R of the dielectric multilayer filter 42, the wavelength components (λj, λk) received at the input port 26a, and the input port 26b. Wavelength component received by
(λi).

Referring to FIG. 4A, since the dielectric multilayer filter 42 transmits the wavelength component (λj), the wavelength component (λj)
Is passed through the filter 42 and provided to the output port 26c.

Referring to FIG. 4B, since the dielectric multilayer filter 42 reflects the wavelength component (λk), the wavelength component (λk) is reflected.
Is reflected by the dielectric multilayer filter 42 and provided to the output port 26d. Further, since the dielectric multilayer filter 42 reflects the wavelength component (λi), the light of the wavelength component (λi) is transmitted through the dielectric multilayer filter 42 after being reflected by the dielectric multilayer filter 42. It is provided to the output port 26c together with the wavelength component (λj).

FIGS. 4C and 4D show the transmission spectrum 44T and the reflection spectrum 44R of the dielectric multilayer filter 44, as well as the wavelength components (λi, λj) received at the input port 28a and the input port 26d. Shows the wavelength component (λk) that is received by.

Referring to FIG. 4C, since the dielectric multilayer filter 44 transmits the wavelength component (λi), the wavelength component (λi)
Is transmitted through the dielectric multilayer filter 44 and provided to the output port 28c.

Referring to FIG. 4D, since the dielectric multilayer filter 44 reflects the wavelength component (λj), the wavelength component (λj)
Is provided to the output port 28b after being reflected. The dielectric multilayer filter 44 has a wavelength component (λk).
After being reflected by the dielectric multilayer filter 44, the wavelength component (λk) is provided to the output port 28c together with the wavelength component (λj) from the input port 28a.

(Third Embodiment) FIG. 5 shows an optical communication system 100 according to the present embodiment. The optical communication system 100 includes an optical transmitter 52, an optical receiver 54, and an ADM device unit 50. In the ADM device unit 50, the ADM device already described or described below is applicable to at least one of the ADM devices 40a, 40b, 40c, and 40d. The input 50a of the ADM unit 50 is optically coupled to the output 52a of the optical transmitter 52 via a transmission line 56a. AD
An output 50b of the M device unit 50 is optically coupled to an input 54a of the optical receiver 54 via a transmission line 56b. The transmission paths 56a and 56b can include various optical devices as needed, for example, optical amplifiers.

The input 50a of the ADM unit 50 is
An optical signal containing one or more wavelength components (λ0, λ1,
λ2, λ3, λ4) from the transmission line 56a. The ADM device 40a receives the light of the add wavelength component (λ5) and extracts the drop wavelength component (λ1). The ADM device 40b receives the light of the add wavelength component (λ6) and extracts the drop wavelength component (λ2). The ADM device 40c receives the light of the add wavelength component (λ7) and extracts the drop wavelength component (λ3). The ADM device 40d receives the light of the add wavelength component (λ8) and extracts the drop wavelength component (λ4). The output 50b of the ADM unit 50 is an optical signal containing one or more wavelength components.
(λ0, λ5, λ6, λ7, λ8) are provided to the transmission path 56b. Thus, light of a plurality of wavelength components can be added and dropped.

The ADM unit 50 shown in FIG.
Are the four ADM devices 40a, 40b, 40c, 40d
, But can generally include one or more ADM devices.

(Fourth Embodiment) FIG. 6 shows an optical ADM apparatus 60 according to still another embodiment. In the optical ADM apparatus 60, the first and second optical devices 26, 28
Is different from the embodiment shown in FIG.

In the optical ADM apparatus 60, the optical signal (λj, λk) from the transmission line is input to the signal input 26, and the optical signal (λi, λ
k) is provided from signal output 28c to the transmission path. The add wavelength component (λi) is input to a signal input 26b, and the drop wavelength component (λj) is provided from a signal output 28b. The optical amplifier 30 generates a drop wavelength component (λj) and an add wavelength component (λ
i) output port 26b of optical device 26 and output port 2 of optical device 28
8a. The diffraction grating 32 is provided between an output port 26d of the optical device 26 and an input port 28d of the optical device 28.

In the optical ADM apparatus 60, the first optical device 26 includes first and second diffraction gratings 62 and 63, and first and second optical couplers 64 and 65, and the second optical device 28 Are the third and fourth diffraction gratings 67,
68, and third and fourth optical couplers 66, 69.

In the first optical device 26, the first optical coupler 64 has a terminal pair composed of terminals 64a and 64d and a terminal pair composed of terminals 64b and 64c.
The optical coupler 65 has a terminal pair including terminals 65a and 65d and a terminal pair including terminals 65b and 65c. Regarding the first optical coupler 64, the paired terminals 64a, 64d
Are the input port 26a and the output port 26, respectively.
c is optically coupled. Counter terminal 64b, 64c
Are optically coupled to pair terminals 65a and 65d of the second optical coupler 65 via diffraction gratings 62 and 63, respectively. Further, with respect to the second optical coupler 65, the pair terminals 65b and 65c are optically coupled to the input port 26b and the output port 26d, respectively.

In the second optical device 28, the third optical coupler 66 has a terminal pair composed of terminals 66a and 66b and a terminal pair composed of terminals 66c and 66d, and the fourth optical coupler 69 has It has a terminal pair consisting of terminals 69a and 69b and a terminal pair consisting of terminals 69c and 69d.
Regarding the third optical coupler 66, the paired terminals 66a, 66b
Are the output port 28b and the input port 28, respectively.
d, and the pair terminals 66c, 66d are optically coupled to the terminal pair 69b, 69a of the fourth optical coupler 69 via the diffraction grating 68 and the diffraction grating 67, respectively. Further, with respect to the fourth optical coupler 69, the pair terminals 69c and 69d are optically coupled to the input port 28a and the output port 28c, respectively.

Each port of the optical devices 26 and 28 has
Optical filters 61a to 61h are provided.

The optical ADM device 60 operates as follows.

In the optical device 26, the optical signal of the wavelength component (λj, λk) input from the input port 26a is
The light is branched at the optical coupler 64 and reaches the terminals 64b and 64c. The diffraction gratings 62 and 63 reflect the wavelength component (λj) and transmit the wavelength component (λk). The reflected wavelength component (λj) is transmitted through the optical coupler 64 to the terminals 64 a and 64
reaches d. The wavelength component reaching the terminal 64a is cut off by the optical filter 61a and does not appear at the input port 26a. On the other hand, the transmitted wavelength component (λk) is branched in the optical coupler 65 and reaches the terminals 65b and 65c.
The wavelength component reaching the terminal 65b is cut off by the optical filter 61b and does not appear at the input port 26b.

Add wavelength component input to input port 26
(λi) is branched at the optical coupler 65 and
a, reaches 65d. The wavelength component (λi) is
2, 63, and a terminal 64 via an optical coupler 64.
a, reaches 64d. The wavelength component reaching the terminal 64a is cut off by the optical filter 61a,
6a does not appear.

Therefore, the light of the wavelength component (λi, λj) is provided from the output port 26c of the optical device 26.
The lights of the wavelength components (λi, λj) are input to the input port 28 a of the optical device 28 after being amplified together by the optical amplifier 30. Also, the output port 26 of the optical device 26
d provides light of a wavelength component (λk). Wavelength component
The light of (λk) passes through the diffraction grating 32 and is input to the input port 28d of the optical device 28.

In the optical device 28, the wavelength component (λi, λj) optical signal input from the input port 28a is split at the optical coupler 69 and reaches the terminals 69a and 69b. The wavelength component (λi) is reflected by the diffraction gratings 67 and 68, and the wavelength component (λj) is transmitted. The reflected wavelength component (λi) is transmitted through the optical coupler 69 to the terminals 69c and 6c.
9d is reached. The wavelength component reaching the terminal 69c is cut off by the optical filter 61g and does not appear at the signal input 28a. On the other hand, the transmitted wavelength component (λj) reaches the terminals 66a and 66b via the optical coupler 66. Terminal 66
The wavelength component reaching b is cut off by the optical filter 61f and does not appear at the input port 28d.

The wavelength component (λ) input to the signal input 28 d
k) is branched at the optical coupler 66 and the terminals 66c, 6
6d is reached. The wavelength component (λk) is
8, after passing through the terminals 69c and 6 via the optical coupler 69.
9d is reached. The wavelength component reaching the terminal 69c is cut off by the optical filter 61g and does not appear at the input port 28a.

Therefore, the light of the wavelength components (λj, λk) is provided from the output port 28c of the optical device 28 to the transmission line. The light of the wavelength component (λj) is provided to the output port 26b of the optical device 28 as a drop wavelength component.

Therefore, by the action of the optical devices 26 and 28, the ADM device 60 extracts the drop wavelength component (λj) from the wavelength components (λj, λk) received from the transmission line and adds the add wavelength component (λi). It is understood that is added. The add wavelength component (λi) and the drop wavelength component (λj) are optically amplified by the common optical amplifier 30.

The optical filters 61c and 61d are connected to the output port 2
By disposing them at 6b and 26d, the inflow of unnecessary wavelength components into the optical device 26 can be reduced. Further, if the optical filters 61e and 61h are arranged at the output ports 28b and 28c, leakage of light of unnecessary wavelength components from the optical device 28 can be reduced.

(Fifth Embodiment) FIG. 7 shows an optical ADM apparatus 70 according to still another embodiment. In the optical ADM device 70, the first, third, and fourth optical couplers 64, 6
Instead of 6 and 69, first, third and fourth optical couplers 74, 76 and 79 having wavelength selectivity are employed.

In the optical ADM apparatus 70 according to the present embodiment, the terminals 74a to 74d of the first optical coupler 74 correspond to the terminals 64a to 64d of the first optical coupler 64 in the optical ADM apparatus 60, respectively. And the third optical coupler 7
4 are connected to the optical ADM device 6 respectively.
0 correspond to the terminals 66a to 66d of the first optical coupler 66 and the terminals 79a to 79d of the fourth optical coupler 79.
“d” corresponds to the terminals 69 a to 69 d of the fourth optical coupler 64 in the optical ADM apparatus 60, respectively. Therefore, a detailed description of the optical ADM device 70 will be omitted.

The optical ADM device 70 operates as follows.

In the optical device 26, the wavelength components (λj, λk) of the optical signal input from the input port 26a are
The light is branched at the optical coupler 74 and reaches the terminals 74b and 74c. The diffraction gratings 62 and 63 reflect the wavelength component (λj) and transmit the wavelength component (λk). The reflected wavelength component (λj) is input to the optical coupler 74 again. Terminal 7
The light of the wavelength component (λj) input from 4b and 74c is selectively coupled in the optical coupler 74. For this reason, the light of the wavelength component (λj) mainly appears at the terminal 74d without substantially appearing at the terminal 74a. The wavelength component reaching the terminal 74a from the optical coupler 74 is cut off by the optical filter 61a and does not appear at the input port 26a. on the other hand,
The transmitted wavelength component (λk) reaches the terminals 74b and 74c via the optical coupler 75. However, terminal 75b
Are also blocked by the optical filter 61b.

Add wavelength component input to input port 26
(λi) is branched at the optical coupler 75 and
a, reaches 75d. The wavelength component (λi) is
After passing through the optical coupler 74, the terminal 74 passes through the optical coupler 74.
a, reaches 74d. The wavelength component reaching the terminal 74a is cut off by the optical filter 61a, and the signal input 26
does not appear in a.

Therefore, the light of the wavelength component (λi, λj) is provided from the output port 26c of the optical device 26.
The lights of the wavelength components (λi, λj) are input to the input port 28 a of the optical device 28 after being amplified together by the optical amplifier 30. Also, the output port 26 of the optical device 26
d provides light of a wavelength component (λk). Wavelength component
The light of (λk) passes through the diffraction grating 32 and is input to the input port 28d of the optical device 28.

In the optical device 28, the wavelength component (λi, λj) optical signal input from the input port 28a is split by the optical coupler 79 and reaches the terminals 79a and 79b. The light having the wavelength component (λi) is reflected by the diffraction gratings 67 and 68, and the light having the wavelength component (λj) is transmitted. The light of the reflected wavelength component (λi) is selectively coupled in the optical coupler 79. Therefore, the light of the wavelength component (λi)
It mainly appears at the terminal 79d without substantially appearing at the terminal 79c. The light of the wavelength component reaching the terminal 79c from the optical coupler 79 is blocked by the optical filter 61g.
On the other hand, the light of the transmitted wavelength component (λj) is selectively coupled in the optical coupler 76. Therefore, the wavelength component (λj)
Does not substantially appear at the terminal 76b,
Appears mainly in 6a. The light of the wavelength component reaching the terminal 67b from the optical coupler 76 is blocked by the optical filter 61f.

The wavelength component input to the input port 28d
(λk) is branched at the optical coupler 76 and the terminal 76
c, reaches 76d. The wavelength component (λk) is
7 and 68, after passing through terminal 79 via optical coupler 79.
c, reaching 79d. The wavelength component reaching the terminal 79c is blocked by the optical filter 61g, and the signal input 28
does not appear in a.

Therefore, light of the wavelength component (λk, λj) is provided from the output port 28c of the optical device 28 to the transmission line. The light of the wavelength component (λj) is provided to the output port 26b of the optical device 28 as a drop wavelength component.

Therefore, by the operation of the optical devices 26 and 28, the ADM device 70 extracts the drop wavelength component (λj) from the wavelength components (λj, λk) received from the transmission line and adds the add wavelength component (λi). It is understood that is added.

As described above, the optical device includes:
It is understood that a Mach-Zehnder type optical circuit configured using an optical coupler can be applied.

Although the embodiments of the present invention have been described with reference to the accompanying drawings, the embodiments of the present invention are not limited to these. For example, instead of each diffraction grating, an optical filter showing equivalent optical spectrum characteristics can be adopted. The diffraction grating includes a fiber grating and a diffraction grating formed on an optical waveguide on a predetermined substrate.

[0072]

As described above in detail, in the optical ADM apparatus according to the present invention, an add wavelength component and a drop wavelength component are selected by processing a wavelength component input to the first optical device. The add and drop wavelength components selected in the first optical device are provided to a second optical device after being amplified together by an optical amplifier. The second optical device selects a drop wavelength component from the input wavelength components and outputs the remaining wavelength component, if any.

Accordingly, an optical ADM device having a simple configuration has been provided.

[Brief description of the drawings]

FIG. 1 is a block diagram of an optical ADM apparatus according to a first embodiment.

FIG. 2 is a block diagram of an optical ADM apparatus according to a second embodiment.

FIGS. 3A to 3D show characteristics of a dielectric multilayer filter.

FIGS. 4A to 4D are diagrams showing the relationship between the characteristics of a dielectric multilayer filter and wavelength components.

FIG. 5 is a block diagram of an optical communication system.

FIG. 6 is a block diagram of an optical ADM apparatus according to a third embodiment.

FIG. 7 is a block diagram of an optical ADM apparatus according to a fourth embodiment.

FIG. 8 is a block diagram of a conventional optical ADM apparatus.

[Explanation of symbols]

22, 24 ... optical transmission line, 26, 28 ... optical device,
Reference numeral 30 denotes an optical amplifier, 32 denotes an optical coupling means (diffraction grating, optical waveguide), 34 denotes an optical multiplexer, 36 denotes an optical demultiplexer, 42,
44: dielectric multilayer filter, 64, 69: optical coupler, 74, 76, 79: wavelength-selective optical coupler,

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04B 10/16 H04Q 3/52

Claims (9)

[Claims] 1. An optical ADM apparatus for adding an add wavelength component to an optical signal including a passing wavelength component and a drop wavelength component, and extracting a drop wavelength component from the optical signal, comprising: A first optical device having a third port and a fourth port, wherein the light of the add wavelength component can pass from the second port to the third port, and the light of the drop wavelength component is A first optical device that can pass from the first port to the third port, and the light of the passing wavelength component can pass from the first port to the fourth port; A second optical device having second, third, and fourth ports, wherein the add wavelength component is transmissible from the first port to the third port, and wherein the drop wavelength component is 1 port And can pass into et said second port, light of the transmission wavelength components fourth
A second optical device that can pass from said port to said third port; and between said third port of said first optical device and said first port of said second optical device. A light comprising: an optical amplifier provided; and an optical coupling unit for optically coupling the fourth port of the first optical device and the fourth port of the second optical device. ADM equipment. 2. The optical device of claim 1, wherein the first optical device comprises:
A first dielectric multilayer filter provided to be optically coupled to the third and fourth ports, wherein the first dielectric multilayer filter is capable of reflecting the light of the passing wavelength component The optical ADM apparatus according to claim 1, wherein the optical ADM apparatus is capable of transmitting the light of the drop wavelength component. 3. The filter according to claim 2, wherein the first dielectric multilayer filter is provided so as to be optically coupled to the second port, and is capable of reflecting the light of the add wavelength component. Optical ADM device. 4. The device according to claim 1, wherein the second optical device comprises:
A second dielectric multilayer filter provided to be optically coupled to the second and third ports, wherein the second dielectric multilayer filter is capable of reflecting light of the drop wavelength component The light A according to any one of claims 1 to 3, wherein the light A is capable of transmitting light of the add wavelength component.
DM device. 5. The filter according to claim 4, wherein the second dielectric multilayer filter is provided so as to be optically coupled to the fourth port, and is capable of reflecting the light of the passing wavelength component. Optical ADM device. 6. The first optical device includes first and second optical filters, and first and second optical couplers each having first to fourth terminals, wherein the first optical device includes: The first terminal of the optical coupler is optically coupled to the first port and the second terminal of the first optical coupler.
Is optically coupled to a first terminal of the second optical coupler via the first optical filter, and the third terminal of the first optical coupler is connected to the second optical filter. Optically coupled to a fourth terminal of the second optical coupler via
The fourth terminal of the first optical coupler is optically coupled to the third port, the second terminal of the second optical coupler is optically coupled to the second port, The optical ADM device according to claim 1, wherein a third terminal of a second optical coupler is optically coupled to the fourth port. 7. The second optical device includes third and fourth optical filters, and third and fourth optical couplers each having first to fourth terminals. The first terminal of the optical coupler is optically coupled to the second port and the second terminal of the third optical coupler.
Terminals are optically coupled to the fourth port, and the third port
The third terminal of the optical coupler is optically coupled to the second terminal of the fourth optical coupler via the fourth optical filter, and the fourth terminal of the third optical coupler is The third
Optically coupled to a first terminal of the fourth optical coupler via an optical filter, a third terminal of the fourth optical coupler is optically coupled to the first port, 7. The optical ADM according to claim 1, wherein a fourth terminal of the fourth optical coupler is optically coupled to the third port.
apparatus. 8. The first and second optical devices,
The optical ADM device according to claim 6, further comprising an optical filter coupled to at least one of the first to fourth ports. 9. The optical coupling means is provided so as to optically couple between a fourth port of the second optical device and the fourth port of the first optical device. The optical ADM device according to claim 1, further comprising a fifth optical filter.