JP2001197001A - Optical device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To select one of two functional devices without external operation nor control. SOLUTION: Two ports 12a and 14a of an up line and two ports 12b and 14b of a down line are led out of a pressure-tight housing 10. Optical circulator 20a and 20b route signal lights through optical equipment 18a when using the port 12a as a signal input port and the port 14a as a signal output port and through optical equipment 16a in the reverse case. The optical circulators 20b and 22b route the signal lights through optical equipment 18b when using the port 12b as a signal input port and the port 14b as a signal output port and through optical equipment 16b in the reverse case.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical device capable of selecting one of two optical functions when connected.

[0002]

2. Description of the Related Art In a long-distance optical fiber transmission system, particularly in a submarine optical cable system, various optical devices (for example, an optical amplifier, a gain equalizer, an optical filter, etc.) are provided therebetween.
However, when connecting to an optical fiber cable, it is necessary to select one having input / output characteristics according to the situation. Therefore, when the required input / output characteristics cannot be determined in advance, a plurality of optical devices having the expected input / output characteristics are prepared, and an appropriate device is selected on site and connected to the optical fiber cable system. Will be.

In particular, in a submarine cable system, it is necessary to house the optical equipment in a pressure-resistant housing that can withstand the pressure in the sea. Since a pressure-resistant housing requires a sufficient manufacturing period and inspection period, it is desirable that a plurality of optical devices be accommodated in one pressure-resistant housing and selected. As such an optical device capable of selecting a plurality of input / output characteristics, a structure in which a plurality of optical devices are simply accommodated, and input and output connection optical fibers are respectively taken out to the outside, an input fiber and an output fiber There is one fiber each, but optical switches are arranged on the input side and output side of a plurality of optical devices having different input / output characteristics, and the optical switches are switched by external control light (or mechanical operation). There is known a configuration in which a control circuit is housed so that a plurality of optical devices can be switched from outside. In optical fiber communication, generally, separate optical fiber lines are used for upstream and downstream, so that a plurality of optical devices for upstream and a plurality of optical devices for downstream are accommodated in one pressure-resistant housing. Become.

A submarine branching device used in a submarine optical cable system is described in, for example, Japanese Patent Application Laid-Open No. 11-41174 (US Patent Application No. 09/118732).

[0005]

In the former configuration, the input fiber and the output fiber for the necessary optical equipment are connected to the optical fiber, and the input fiber and the output fiber for the other optical equipment which are not used are connected. Be left alone. In this case, it is necessary to prepare a sufficient number of optical fiber outlets (feedthroughs) in the pressure-resistant housing in advance. The number of feedthroughs is limited due to the limitation of the size of the feedthrough for the pressure-resistant housing and the requirement of sufficient quality control. Therefore, it cannot be used in a system in which more than the number of prepared feedthroughs must be accommodated in one pressure-resistant housing.

In the latter configuration, since the optical switch is controlled by a control signal including an optical signal or an electric signal from the outside, a circuit for detecting the control signal and a control circuit for switching the optical switch according to the control signal are provided. In addition to this, a power supply system for supplying power to these circuits is also required.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an optical device capable of selecting a desired input / output characteristic without an external operation or control.

Another object of the present invention is to provide an optical device capable of selecting a desired characteristic from two input / output characteristics with minimum feedthrough.

[0009]

An optical device according to the present invention includes first, second, and third ports, respectively, and a first port.
First and second optical circulators for outputting input light of a port from a second port and outputting input light of a second port from a third port; a third port of the first optical circulator; A first optical device connected between the first port of the optical circulator and an optical device having different input / output characteristics from the first optical device; A second optical device connected to the third port of the second optical circulator.

With this configuration, when signal light is input to the second port of the first optical circulator, the first
Can be extracted from the second port of the second optical circulator. Conversely, when signal light is input to the second port of the second optical circulator, light transmitted through the second optical device can be extracted from the second port of the first optical circulator. Therefore,
By simply reversing the connection direction, the first optical device or the second optical device can be selected.

The provision of the first and second optical circulators and the housing for accommodating the first and second optical devices facilitates transportation and maintenance. The adoption of a pressure-resistant housing makes it applicable to submarine optical cable systems. In this case, it is preferable that the signal input / output port is drawn out to the outside in advance. By arranging the first signal light port and the second signal light port on different sides of the housing, the installation or connection of the device can be performed. It will be easier.

By equipping a unit for the opposite direction,
This facilitates application to an optical transmission system using separate optical fiber lines for upstream and downstream. That is, the third and fourth ports respectively include first, second, and third ports, output input light of the first port from the second port, and output input light of the second port from the third port. Light circulator and
An optical device having the same input / output characteristics as the first optical device, wherein the third optical device is connected between a third port of the third optical circulator and a first port of the fourth optical circulator. And an optical device having the same input / output characteristics as the second optical device, wherein an optical device is provided between the first port of the third optical circulator and the third port of the fourth optical circulator. And a fourth optical device to be connected.

In this case, the first, second, third and fourth
It is preferable that the optical circulator and the first, second, third, and fourth optical devices are housed in one housing. This facilitates transport and maintenance. The adoption of a pressure-resistant housing makes it applicable to submarine optical cable systems. A first signal light port connected to the second port of the first optical circulator and a fourth signal light port connected to the second port of the fourth optical circulator are arranged on one side outside the housing. A second signal light port connected to the second port of the second optical circulator and a third signal light port connected to the second port of the third optical circulator are provided on the other side outside the housing. By arranging, installation or connection of this device becomes easy.

The optical device according to the present invention has first and second optical devices, respectively.
It has second, third and fourth ports, outputs input light of the first port from the second port, and outputs input light of the second port to the third port.
First and second optical circulators that output light from a port, output input light from a third port from a fourth port, and output input light from a fourth port from the first port; and the first and second optical circulators of the first optical circulator. A first reflector connected between one port and a first port of the second optical circulator, and a reflector having different reflection characteristics from the first optical device, wherein the first light A second reflector connected between the third port of the circulator and the third port of the second optical circulator.

[0015] With this configuration, the first reflector is determined depending on whether the signal light from the trunk station is input to the fourth port of the first optical circulator or to the second port of the second optical circulator. Alternatively, a second reflector can be selected. Therefore, the add / drop wavelength can be selected only by reversing the connection direction.

The provision of the first and second optical circulators and the housing for accommodating the first and second reflectors facilitates transportation and maintenance. The adoption of a pressure-resistant housing makes it applicable to submarine optical cable systems. In that case, it is preferable that the signal input / output port is drawn out to the outside in advance, the first signal light port is arranged on the first side outside the casing, and the second signal light port is located outside the casing. By arranging on the second side opposite to the first side and arranging the third and fourth signal ports on a third side different from the first and second sides, Installation or connection becomes easy.

By equipping the unit for the opposite direction,
This facilitates application to an optical transmission system using separate optical fiber lines for upstream and downstream. In other words, the apparatus further includes first, second, third, and fourth ports, respectively, and outputs input light of the first port from the second port, and outputs input light of the second port from the third port. Third and fourth optical circulators that output input light of three ports from a fourth port and output input light of a fourth port from a first port;
A reflector having the same reflection characteristics as the reflector of (a), wherein a third reflector connected between the first port of the third optical circulator and the first port of the fourth optical circulator; A reflector having the same reflection characteristics as the second reflector, wherein the fourth reflector is connected between a third port of the third optical circulator and a third port of the fourth optical circulator. And a reflector.

In this case, the first, second, third and fourth
It is preferable to house the optical circulator and the first, second, third and fourth reflectors in one housing. This facilitates transport and maintenance. The adoption of a pressure-resistant housing makes it applicable to submarine optical cable systems.

A first signal light port connected to the fourth port of the first optical circulator and a sixth signal light port connected to the second port of the fourth optical circulator are connected to a first signal light port outside the housing. And a fifth signal light port connected to the second port of the second optical circulator and a fifth signal light port connected to the fourth port of the third optical circulator. A third signal light port connected to a second port of the first optical circulator, and a third signal light port connected to a second port of the first optical circulator, A seventh signal light port to be connected, and an eighth signal light port to be connected to the fourth port of the fourth optical circulator.
By arranging the signal light port on the third side different from the first and second sides, installation or connection of the present apparatus is facilitated.

[0020]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a schematic block diagram of one embodiment of the present invention. Reference numeral 10 denotes a pressure-resistant housing, which includes two ports 12a and 14a for the uplink and two ports 12a for the downlink.
b and 14b are taken out of the pressure-resistant housing 10.

In the pressure-resistant housing 10, two optical devices 16a and 18a and the port 12a are signal input ports (therefore, the port 14a is a signal output port) or the port 14a is a signal input port for ascending. (Thus, port 1
Optical circulators 20a and 22a for inputting and outputting signal light to and from the optical device 16a or the optical device 18a are accommodated depending on whether the signal output port 2a is a signal output port. Pressure-resistant housing 1
0 further includes two optical devices 16b and 18b for downlink.
And port 12b to the signal input port (therefore, port 1
4b is a signal output port, or port 14b is a signal input port (accordingly, port 12b is a signal output port).
Optical circulators 20b and 22 for inputting and outputting signal light to and from the optical device 16b or the optical device 18b.
b.

Optical circulators 20a, 20b, 22
a, 22b both have three ports A, B, C,
The input light of port A is transferred to port B and output from port B, and the input light of port B is transferred to port C and output to port C.
This is an optical element output from.

The port A of the optical circulator 20a is connected to the output of the optical device 16a, the port B is connected to the port 12a, and the port C is connected to the input of the optical device 18a.
Port A of optical circulator 22a connects to the output of optical device 18a, port B connects to port 14a, and port C connects to the input of optical device 16a.

The port A of the optical circulator 20b is connected to the output of the optical device 16b, the port B is connected to the port 12b, and the port C is connected to the input of the optical device 18b.
Port A of optical circulator 22b connects to the output of optical device 18b, port B connects to port 14b, and port C connects to the input of optical device 16b.

FIG. 2 is a schematic diagram showing the flow of signal light when the ports 12a and 12b are signal input ports and the ports 14a and 14b are signal output ports. That is, between the terminal stations A and B, the ports 12a and 14b are on the side of the terminal station A, and the ports 12b and 14a are on the side of the terminal station B. To terminal stations A and B
It is assumed that it is inserted into an optical transmission path between the two. Terminal A
It is needless to say that a repeater having the same configuration as the device 10 or a relay having a different configuration may be arranged between the terminal 10 and the terminal 10 and / or between the terminal B and the device 10.

The flow of signal light in the case of FIG. 2 will be described. The signal light Sa output from the terminal station A to the terminal station B is input to the port 12a. The signal light Sa enters the optical device 18a from the port 12a via the ports B and C of the optical circulator 20a. The signal light Sa output from the optical device 18a reaches the port 14a via the ports A and B of the optical circulator 22a, and is output toward the terminal B. On the other hand, the signal light Sb output from the terminal station B toward the terminal station A is input to the port 12b. The signal light Sb enters the optical device 18b from the port 12b via the ports B and C of the optical circulator 20b. The signal light Sb output from the optical device 18b reaches the port 14b via the ports A and B of the optical circulator 22b, and is output toward the terminal station A.

FIG. 3 is a view opposite to FIG.
FIG. 4 is a schematic diagram showing the flow of signal light when 4b is a signal input port and ports 12a and 12b are signal output ports. That is, the port 12 is connected between the terminal A and the terminal B.
b, 14a are located on the terminal A side, and the ports 12a, 14b
It is assumed that the apparatus of the embodiment shown in FIG.

The flow of signal light in the case shown in FIG. 3 will be described. The signal light Sa output from the terminal station A to the terminal station B is input to the port 14a. The signal light Sa is supplied to the port 14
a to port C and port C of the optical circulator 22a
And enters the optical device 16a. Optical equipment 16a
The signal light Sa output from the optical circulator 20 reaches the port 12a via the ports A and B of the optical circulator 20a, and is output to the terminal station B. On the other hand, the signal light Sb output from the terminal station B toward the terminal station A is input to the port 14b.
The signal light Sb is supplied from the port 14b to the optical circulator 2
Optical device 16b via port B and port C of 2b
Incident on. The signal light Sb output from the optical device 16b reaches the port 12b via the ports A and B of the optical circulator 20b, and is output toward the terminal A.

As described above, in the present embodiment, when the optical fiber is inserted into the optical fiber line, the port 12a (12b) and the port 1
4a (14b) as the signal input side,
The optical device 16a (16b) or the optical device 18a (18
b) can be selected. Element requiring power supply is pressure-resistant housing 1
Since there is no need to house the power supply inside the power supply 0, a power supply system is unnecessary. Neither a control signal for selecting input / output characteristics nor an operation member is required. The optical devices 16a, 16b, 18a, and 18b include, for example, an optical amplifier (for example, a low-gain optical amplifier and a high-gain optical amplifier), a gain equalizer, a dispersion equalizer, and an optical filter (for example, a high-pass filter). Low-pass filter). According to this embodiment, it is possible to realize a small and inexpensive equalizer, repeater, and the like that can freely select a desired one from two input / output characteristics.

In this embodiment, the transfer function differs depending on the propagation direction of the signal light. Therefore, for example, even when it is desired to impart a transmission characteristic different from that of the signal light to light propagating in the opposite direction to the signal light propagation direction (for example, return light for line monitoring and reflected light for failure detection). This embodiment is effective.

Preferably, ports 12a and 14b are located on the same side of housing 10, and ports 14a and 12b are located on the same opposite side. This facilitates installation or connection of the device.

FIG. 4 is a schematic block diagram of an embodiment of the present invention applied to a wavelength branching type underwater branching device, a so-called optical add / drop device.

Reference numeral 110 denotes a pressure-resistant housing, which is used for an up line.
Port 112a, 114a and two downlink ports 112b, 114b, port 1 connected to the branch station
Portions 18a, 118b, 120a, and 120b, and ports 120a, 120b, 122a, and 122b for signal light merely passing through the pressure-resistant housing 110 are taken out of the pressure-resistant housing 110.

In the pressure-resistant housing 110, two fiber gratings 124a and 126a having reflection wavelengths λa and λb different from each other and a port 112a are connected to a signal input port (accordingly, the port 114a is set to a signal output port). Or the port 114a is a signal input port (therefore, the port 112a is a signal output port).
Optical circulators 128a and 130 inputting and outputting to 26a
a is housed. The pressure-resistant housing 110 is further provided with two fiber gratings 124b and 126b having different reflection wavelengths λa and λb and a port 112b as a signal input port (accordingly, the port 114b is a signal output port) for downlink. , And the port 114b is a signal input port (therefore, the port 112b is a signal output port).
Optical circulator 128 for input / output to / from 4b or 126b
b, 130b.

Optical circulators 128a, 128b, 1
Both 30a and 130b have four ports A, B, C and D
, The input light of port A is transferred to port B and output from port B, the input light of port B is transferred to port C and output from port C, and the input light of port C is transferred to port D. This is an optical element that outputs from port D, transfers input light of port D to port A, and outputs from port A.

Port A of optical circulator 128a is connected to one end of fiber grating 124a, port B is connected to port 116a, port C is connected to one end of fiber grating 126a, and port D is connected to port 112a. Port A of optical circulator 130a is connected to the other end of fiber grating 124a, port B is connected to port 114a, port C is connected to the other end of fiber grating 126a, and port D is connected to port 118a.

Port A of optical circulator 128b is connected to one end of fiber grating 124b, port B is connected to port 116b, port C is connected to one end of fiber grating 126b, and port D is connected to port 112b. Port A of optical circulator 130b is connected to the other end of fiber grating 124b, port B is connected to port 114b, port C is connected to the other end of fiber grating 126b, and port D is connected to port 118b.

The ports 120a and 122a are connected to the optical fiber 1
32a, the ports 120b, 122
b are mutually connected via an optical fiber 132b. As can be seen, the ports 120a, 120b, 12
Reference numerals 2a and 122b are used to interconnect the optical fibers of the trunk cable for transmitting the signal light independent of the branch station.

In the embodiment shown in FIG. 4, depending on the connection direction,
That is, by setting the ports 112a and 112b on the input side (therefore, the ports 114a and 114b on the output side) or vice versa, the signal light (wavelength) to be dropped to the branch station can be selected from λa and λb.

FIG. 5 shows the flow of signal light when the ports 112a and 112b are on the signal input side (therefore, the ports 114a and 114b are on the signal output side). Trunk station A,
The device shown in FIG. 4 is inserted on the optical transmission line between B and B.
Here, for ease of understanding, trunk station A is:
Signal light S0 of wavelength λb directed to trunk station B and branch station C
To the port 112a, and the trunk station B sends the signal light S3 of the wavelength λb directed to the trunk station A and the signal light S4 of the wavelength λa directed to the branch station C to the port 112b. The branch station C outputs the signal light S2 having the wavelength λa toward the trunk station B to the port 118a, and outputs the signal light S5 having the wavelength λa toward the trunk station A.
Output to port 118b. Each signal S0
The flow of S5 is illustrated by a thick solid line. The unused fiber gratings 126a and 126b and the path through which the signal light does not propagate are shown by broken lines.

The signal light S0 (λb) input from the trunk station A to the port 112a enters the fiber grating 124a via the ports D and A of the optical circulator 128a. Fiber grating 124
Since the reflection wavelength of a is λa, which is different from the wavelength λb of the signal light S0, the signal light S0 (λb) passes through the fiber grating 124a with substantially no loss. Signal light S0 (λb) transmitted through fiber grating 124a
Are the ports A and B of the optical circulator 130a.
, And is output from the port 114a to the trunk station B.

The signal light S1 (λa) input from the trunk station A to the port 112a is also transmitted to the optical circulator 128.
The light enters the fiber grating 124a via the port D and the port A. Fiber grating 1
24a is λa, and the wavelength λa of the signal light S1 is
Therefore, the signal light S1 (λa) is reflected by the fiber grating 124a, returns to the port A of the optical circulator 128a, is transferred to the port B, and
The signal is supplied to the branch station C from the port 116a.

The branch station C also outputs the signal light S2 (λa) directed to the trunk station B to the port 118a. The signal light S2 (λa) passes through the ports D and A of the optical circulator 130a from the port 118a and enters the fiber grating 124a. The reflection wavelength of the fiber grating 124a is λa, and the signal light S2
Therefore, the signal light S2 (λa) is reflected by the fiber grating 124a, returns to the port A of the optical circulator 130a, is transferred to the port B, and is supplied from the port 114a to the trunk station B.

The signal light S3 (λb) input from the trunk station B to the port 112b enters the fiber grating 124b via the ports D and A of the optical circulator 128b. Fiber grating 124
Since the reflection wavelength of b is λa, which is different from the wavelength λb of the signal light S3, the signal light S3 (λb) passes through the fiber grating 124b with substantially no loss. The signal light S3 (λb) transmitted through the fiber grating 124b
Are the ports A and B of the optical circulator 130b.
And output from the port 114b toward the trunk station A.

The signal light S 4 (λa) input from the trunk station B to the port 112 b is also transmitted to the optical circulator 128.
Then, the light enters the fiber grating 124b via the port D and the port A of FIG. Fiber grating 1
24b is λa, and the wavelength λa of the signal light S4 is
Therefore, the signal light S4 (λa) is reflected by the fiber grating 124b, returns to the port A of the optical circulator 128b, and is transferred to the port B.
The signal is supplied to the branch station C from the port 116b.

The branch station C also outputs the signal light S5 (λa) directed to the trunk station A to the port 118b. The signal light S5 (λa) passes through the ports D and A of the optical circulator 130b from the port 118b and enters the fiber grating 124b. The reflection wavelength of the fiber grating 124b is λa, and the signal light S5
Therefore, the signal light S5 (λa) is reflected by the fiber grating 124b, returns to the port A of the optical circulator 130b, is transferred to the port B, and is supplied from the port 114b to the trunk station A.

FIG. 6 shows a port 114a,
114b is connected to the signal input side (therefore, ports 112a, 11
2b shows the flow of signal light when the signal output side is 2b.
In order to facilitate understanding, the trunk station A outputs a signal S0 of the wavelength λa directed to the trunk station B and a signal S1 of the wavelength λb directed to the branch station C to the port 114a. A signal S3 of wavelength λa directed to A and a signal light S4 of wavelength λb directed to branch station C are output to port 114b, and branch station C outputs a signal light S2 of wavelength λb directed to trunk station B to port 116a. And outputs the signal light S5 having the wavelength λb toward the trunk station A to the port 116b.
Output to The flow of each signal S0 to S5 is shown by a thick solid line. The unused fiber gratings 124a and 124b and the path through which the signal light does not propagate are shown by broken lines.

The signal light S0 (λa) input from the trunk station A to the port 114a enters the fiber grating 126a via the ports B and C of the optical circulator 130a. Fiber grating 126
Since the reflection wavelength of a is λb, which is different from the wavelength λa of the signal light S0, the signal light S0 (λa) passes through the fiber grating 126a with substantially no loss. Signal light S0 (λa) transmitted through fiber grating 126a
Are the ports C and D of the optical circulator 128a.
And is output from the port 112a toward the trunk station B.

The signal light S1 (λb) input from the trunk station A to the port 114a is also transmitted to the optical circulator 130.
The light enters the fiber grating 126a via the port B and the port C of FIG. Fiber grating 1
26a is λb, and the wavelength λb of the signal light S1 is
Therefore, the signal light S1 (λa) is reflected by the fiber grating 126a, returns to the port C of the optical circulator 130a, is transferred to the port D,
The signal is supplied to the branch station C from the port 118a.

The branch station C also outputs the signal light S2 (λb) directed to the trunk station B to the port 116a. The signal light S2 (λb) passes through the ports B and C of the optical circulator 128a from the port 116a and enters the fiber grating 126a. The reflection wavelength of the fiber grating 126a is λb, and the signal light S2
Therefore, the signal light S2 (λb) is reflected by the fiber grating 126a, returns to the port C of the optical circulator 128a, is transferred to the port D, and is supplied from the port 112a to the trunk station B.

The signal light S3 (λa) input from the trunk station B to the port 114b enters the fiber grating 126b via the ports B and C of the optical circulator 130b. Fiber grating 126
Since the reflection wavelength of b is λb, which is different from the wavelength λa of the signal light S3, the signal light S3 (λa) passes through the fiber grating 126b with substantially no loss. The signal light S3 (λa) transmitted through the fiber grating 126b
Are the ports C and D of the optical circulator 128b.
, And is output from the port 112b to the trunk station A.

The signal light S4 (λb) input from the trunk station B to the port 114b is also transmitted to the optical circulator 130.
The light enters the fiber grating 126b via the port B and the port C of FIG. Fiber grating 1
The reflection wavelength of 26b is λb, and the wavelength λb of the signal light S4 is
Therefore, the signal light S4 (λb) is reflected by the fiber grating 124b, returns to the port C of the optical circulator 130b, is transferred to the port D, and
The signal is supplied to the branch station C from the port 118b.

The branch station C also outputs the signal light S5 (λb) directed to the trunk station A to the port 116b. The signal light S5 (λb) passes through the ports B and C of the optical circulator 128b from the port 116b and enters the fiber grating 126b. The reflection wavelength of the fiber grating 126b is λb, and the signal light S5
Therefore, the signal light S5 (λb) is reflected by the fiber grating 126b, returns to the port C of the optical circulator 128b, is transferred to the port D, and is supplied from the port 112b to the trunk station A.

In this manner, the wavelength λa or λb can be set as the add / drop wavelength by simply changing the connection side.
Can be selected.

Preferably, ports 112a and 114b are located on the same side of housing 110 and ports 114a and 112b are located together on the opposite side. Port 116
Preferably, a, 116b, 118a, and 118b are taken out from the third side of the housing 110 different from any of these. This facilitates installation or connection of the device.

[0057]

As can be easily understood from the above description, according to the present invention, while having a very simple structure,
One of two input / output characteristics can be selected simply by changing the connection direction. The number of outlets to be prepared outside can be reduced. It is possible to reduce the number of units or the number of housings that house a plurality of functional devices (optical devices such as a gain equalizer and an optical amplifier).

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a first embodiment of the present invention.

FIG. 2 is a schematic diagram showing a flow of signal light in the embodiment shown in FIG.

FIG. 3 is a schematic diagram showing the flow of signal light when the embodiment shown in FIG. 1 is connected in the reverse direction.

FIG. 4 is a schematic configuration diagram of a second embodiment of the present invention.

FIG. 5 is a schematic diagram showing the flow of signal light in the embodiment shown in FIG.

FIG. 6 is a schematic diagram showing the flow of signal light when the embodiment shown in FIG. 4 is connected in the reverse direction.

[Explanation of symbols]

10: pressure-resistant housing 12a, 12b, 14a, 14b: port 16a, 16b, 18a, 18b: optical device 20a, 20b, 22a, 22b: optical circulator 110: pressure-resistant housing 112a, 112b, 114a, 114b: port 116a, 116b, 118a, 118b: ports 120a, 120b, 122a, 122b: ports 124a, 124b: fiber grating (reflection wavelength λa) 126a, 126b: fiber grating (reflection wavelength λb) 128a, 128b, 130a, 130b: optical circulator 132a, 132b: Optical fiber

Claims (19)

[Claims] A first and a second port respectively having a first, a second and a third port for outputting input light of a first port from a second port and outputting input light of a second port from a third port. 2 optical circulators, and a first optical circulator connected between a third port of the first optical circulator and a first port of the second optical circulator.
And an optical device having different input / output characteristics from the first optical device, wherein the optical device is connected between a first port of the first optical circulator and a third port of the second optical circulator. An optical device, comprising: a second optical device to be used. 2. The optical device according to claim 1, further comprising a housing for housing said first and second optical circulators and said first and second optical devices. 3. The optical device according to claim 2, wherein the housing is a pressure-resistant housing. 4. A first signal light port connected to a second port of the first optical circulator, and a second signal light port connected to a second port of the second optical circulator. 3. The device according to claim 2, wherein the first signal light port is arranged on one side outside the casing, and the second signal light port is arranged on the other side outside the casing. Optical device. And a third port for outputting input light from the first port from the second port and outputting input light from the second port from the third port. And a fourth optical circulator, and an optical device having the same input / output characteristics as the first optical device, wherein a third port of the third optical circulator and a first port of the fourth optical circulator are provided. A third optical device connected between the first optical device and an optical device having the same input / output characteristics as the second optical device, wherein the first port of the third optical circulator and the fourth optical circulator are provided. The optical device according to claim 1, further comprising: a fourth optical device connected to the third port. 6. The first, second, third, and fourth optical circulators, and the first, second, third, and fourth optical circulators.
The optical device according to claim 5, further comprising a housing accommodating the optical device. 7. The optical device according to claim 6, wherein the housing is a pressure-resistant housing. 8. A first signal light port connected to the second port of the first optical circulator, a second signal light port connected to the second port of the second optical circulator, and the second signal light port. The second of the optical circulator of No. 3
A third signal light port connected to the port; and a fourth signal light port connected to the second port of the fourth optical circulator, wherein the first and fourth signal light ports are provided in the housing. Is located on one side outside the
The optical device according to claim 6, wherein the third signal light port is disposed on the other side outside the housing. 9. The optical device according to claim 1, wherein the optical device comprises an optical amplifier. 10. The optical device according to claim 1, wherein the optical device comprises an optical filter. 11. The optical device according to claim 1, wherein the optical device comprises a dispersion equalizer. And a first port, a second port, a third port and a fourth port, respectively, wherein input light of the first port is output from the second port, input light of the second port is output from the third port, First and second optical circulators for outputting input light of the third port from the fourth port and outputting input light of the fourth port from the first port; a first port of the first optical circulator; A second port connected to a first port of the second optical circulator;
And a reflector having different reflection characteristics from the first optical device, and connected between a third port of the first optical circulator and a third port of the second optical circulator. And a second reflector. 13. The optical device according to claim 12, further comprising a housing for housing said first and second optical circulators and said first and second reflectors. 14. The housing according to claim 13, wherein said housing is a pressure-resistant housing.
An optical device according to claim 1. 15. A first signal light port connected to a fourth port of the first optical circulator, a second signal light port connected to a second port of the second optical circulator, A third signal light port connected to a second port of the first optical circulator; and a fourth signal light port connected to a fourth port of the second optical circulator, wherein the first signal light is provided. A port located on a first side outside the housing, the second signal light port located on a second side outside the housing opposite the first side, and a third 14. The optical device according to claim 13, wherein the fourth and fourth signal ports are arranged on a third side different from the first and second sides. 16. A semiconductor device further comprising first, second, third and fourth ports, respectively, wherein input light of the first port is output from the second port, and input light of the second port is output from the third port. The third and fourth optical circulators that output the input light of the third port from the fourth port and output the input light of the fourth port from the first port have the same reflection characteristics as the first reflector. A reflector comprising: a third reflector connected between a first port of the third optical circulator and a first port of the fourth optical circulator; and a second reflector. A reflector having the same reflection characteristics, comprising a fourth reflector connected between a third port of the third optical circulator and a third port of the fourth optical circulator. Item 13. The optical device according to Item 12. 17. The method according to claim 17, further comprising the steps of:
The optical device according to claim 16, further comprising a housing accommodating the optical circulator and the first, second, third, and fourth reflectors. 18. The housing according to claim 17, wherein said housing is a pressure-resistant housing.
An optical device according to claim 1. 19. A first signal light port connected to a fourth port of the first optical circulator, a second signal light port connected to a second port of the second optical circulator, A third signal light port connected to the second port of the first optical circulator; a fourth signal light port connected to the fourth port of the second optical circulator; and a fourth signal light port of the third optical circulator.
A fifth signal light port connected to the port, a sixth signal light port connected to the second port of the fourth optical circulator, and a seventh signal connected to the second port of the third optical circulator An optical port, and an eighth signal light port connected to the fourth port of the fourth optical circulator, wherein the first and sixth signal light ports are on a first side outside the housing. And wherein the second and fifth signal light ports are disposed on a second side outside the housing opposite to the first side and the third, fourth, seventh and eighth ports are disposed. 18. The optical device according to claim 17, wherein the signal port is located on a third side different from the first and second sides.