JPH08304855A - Prestage module and poststage module for optical amplifier - Google Patents

Abstract

PURPOSE: To make miniaturization possible and to prevent an output of a signal beam from being lowered by reducing welding positions and reducing a welding loss. CONSTITUTION: A prestage module for an optical amplifier is constituted so that collimators 3, 4 respectively arranged on the incident side and the out-going side of the signal beam, a non-polarizing beam splitter 5 arranged between both collimators, a photodiode 6 receiving a part of the signal beam from the incident side collimator 3 through the beam splitter and a polarization independence type optical isolator 2 arranged between the beam splitter and the outgoing side collimator 4 are respectively and integrally mounted in a packing vessel P1, and the outgoing collimator 5 is connected to a rare-earth dope optical fiber F.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pre-stage module and a post-stage module for an optical amplifier for enabling miniaturization.

[0002]

2. Description of the Related Art Optical fiber amplifiers have been conventionally known. The configuration of this optical fiber amplifier will be described with reference to FIGS. The signal light having a wavelength of 1550 nm is incident on the coupler C1 and a part of the signal light is used for monitoring, but most of it is the optical isolator IS1.
And is sent to the rare earth-doped optical fiber EF. Excitation light having a wavelength of 1480 nm is sent from the optical multiplexer / demultiplexer WDM to the rare earth-doped optical fiber EF, and the signal light passing through the rare earth-doped optical fiber is amplified and emitted from this optical multiplexer / demultiplexer to be an optical isolator. Coupler C2 through IS2
A part of it is used for amplifier monitoring, but most of it is output as output signal light. Specific configurations of the couplers C1 and C2, which are optical passive components (optical passive components), the optical isolators IS1 and IS2, and the optical multiplexer / demultiplexer WDM will be described with reference to FIG. The coupler C1 has collimators 101 and 102, which form terminals on both sides thereof, face each other, and a beam splitter 103 is arranged between the two collimators. The signal light emitted from the collimator 101 passes through the beam splitter. Part of the light is reflected and sent to the monitor photodiode 104. The configuration of the coupler C2 is also substantially the same as that of the coupler C1. 1
Reference numerals 11 and 112 denote collimators forming terminals, and 113.
Is a beam splitter, and 114 is a photodiode for an amplifier monitor. The optical isolator IS1 has collimators 201 and 202 forming terminals on opposite sides thereof, which are opposed to each other, and an optical isolator main body 203 is disposed between the collimators. One (left) collimator 201 is connected to the collimator 102 of the coupler C1 via an optical fiber, and the other collimator 202 is connected.
Is connected to one end of the rare earth-doped optical fiber EF. The configuration of the optical isolator IS2 is the optical isolator I
It is substantially the same as that of S1. 211 and 212 are collimators and 213 is an optical isolator main body. The exit side collimator 212 is connected to the entrance side collimator 111 of the coupler C2 via an optical fiber. The optical multiplexer / demultiplexer WDM includes a collimator 301 connected to one end (left side) of the rare earth-doped optical fiber EF, and a collimator 303 located opposite to the collimator 301 on the other side.
And a long wave transmission filter 3 placed between both collimators
04, and a collimator 302 which is located on the same side as the collimator 301 and emits the excitation light. The excitation light having a wavelength of 1480 nm is converted by the collimator 302
When it is emitted from the optical fiber EF, it is reflected by the long-wave transmission filter 304 and sent to the rare earth-doped optical fiber EF. For this,
In the rare earth-doped optical fiber, the signal light having a wavelength of 1550 nm is amplified and output from the collimator 303 to the optical isolator main body 213 via the optical fiber and the collimator 211 of the optical isolator IS2.

[0003]

According to the conventional example, since each optical passive component is connected to an optical fiber by using a collimator, the number of components tends to increase and the size tends to increase. Since there are many fusion points with the fiber, there is a problem that the fusion loss increases and the output of the signal light decreases. An object of the present invention is to enable downsizing, reduce the number of fusion points to reduce fusion loss, and prevent the output of signal light from dropping.

[0004]

A pre-stage module for an optical amplifier according to the present invention integrates an optical branching / coupling device, a light receiving device and an optical isolator. The pre-stage module for an optical amplifier according to the present invention is provided with terminals, for example, a collimator arranged on the incident side and the emission side of signal light, and a separating means, for example, a beam splitter, arranged between both terminals, and this separating unit. A light receiving device for receiving a part of the signal light from the incident side terminal via the means, and an optical isolator arranged between the separating means and the emitting side terminal, respectively. The terminal on the output side is connected to the rare earth-doped optical fiber.
A non-polarizing beam splitter or the like is used as the beam splitter that is the separating means, a photodiode or the like is used as the light receiving device, and a polarization-independent optical isolator or the like is used as the optical isolator.

The post-stage module for an optical amplifier according to the present invention integrates an optical multiplexer / demultiplexer, an optical isolator, a light receiving device and an optical branching / coupling device. The post-stage module for the optical amplifier of the present invention is arranged on the incident side of the signal light respectively, one of which is connected to the rare-earth-doped optical fiber, for example, a collimator, and the other of which is a terminal for pumping light, for example, A collimator, a wavelength division multiplexing filter for multiplexing and demultiplexing the signal light emitted from the one terminal and the excitation light emitted from the other terminal with the respective wavelengths,
An optical isolator on which the signal light transmitted through this wavelength division multiplexing filter is incident, and a terminal which is arranged on the output side of the signal light which is the opposite side to the terminal, and which outputs the signal light,
Separation means, such as a beam splitter, arranged between the terminal on the output side and the optical isolator, and a light-receiving device for receiving a part of the signal light from the optical isolator via the separation means are integrated respectively. There is something. A polarization-independent optical isolator is used as the optical isolator, a non-polarization beam splitter is used as the beam splitter that is the separating means, a photodiode is used as the light receiving device, and a long-wave transmission filter is used as the wavelength division multiplexing filter. .

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS. As shown in FIG. 1, the optical fiber amplifier includes an optical amplifier pre-stage module A on both sides of the input and output of the rare earth-doped optical fiber F, that is, the input side (left side in the figure) and the optical amplifier on the output side (right side in the figure). Each of the post-operation modules B is provided. As the rare earth-doped optical fiber F, an erbium-doped optical fiber is used in this example. 1550
The input signal light of nm is propagated into the rare earth-doped optical fiber F through the optical amplifier front-end module A.
Since the 1480 nm excitation light reflected from the filter is sent, the input signal light is amplified and output via the optical amplifier rear-stage module B.

[0007] First, a specific structure of the optical amplifier front stage module A will be described. As shown in FIG. 1, the front-end module A for an optical amplifier is provided with an optical branching / coupling device 1, an optical isolator 2, and a light receiving device 6 which are optical passive components, and is characterized in that these elements are integrated. However, the more detailed configuration is as shown in FIG.
That is, the collimator 3 forming a terminal on the incident side (left side in the drawing) of the signal light and the collimator 4 forming a terminal on the emitting side (right side in the drawing) are arranged in a facing positional relationship. Is connected to one end (left end in the figure) of the rare earth-doped optical fiber F. Collimator 3 on the incident side
A beam splitter 5 which is a separating means is arranged near the exit side of the input signal light, and the non-polarizing beam splitter 5 is used as the beam splitter in this example. The beam splitter 5 is about 95% of the input signal light.
%, And about 5% is reflected and guided to the photodiode 6, which is a light receiving device below. The photodiode 6 is electrically connected to a signal monitor (not shown). An optical isolator 2 is arranged between the beam splitter 5 and the collimator 4 on the emission side.
As this optical isolator, a polarization-independent optical isolator is used in this example. The optical isolator 2, the collimators 3 and 4, the beam splitter 5, and the photodiode 6 are integrated into the packaging container P1. Since the front-end module A for optical amplifier has the configuration of the above example, 1
When the signal light of 550 nm is input to the incident side collimator 3 and is condensed and reaches the beam splitter 5, it is separated into two directions here, and on the other hand, about 95% of the signal light is transmitted through the beam splitter 5, After passing through the optical isolator 2, the light is condensed by the collimator 4 on the emission side and propagated to the rare earth-doped optical fiber F. On the other hand, about 5% of the signal light is output to the photodiode 6 and used for signal monitoring.

Next, a specific configuration of the optical amplifier rear-stage module B will be described. The post-stage module B for optical amplifier is
As shown in FIG. 1, an optical multiplexer / demultiplexer 7, an optical isolator 8, a light receiving device 15, and an optical branching / coupling device 9 which are optical passive components.
And is characterized in that these elements are integrated, and a more detailed configuration is as shown in FIG. That is, the collimators 10 and 11 forming terminals are arranged on the incident side (left side in the drawing), and the collimators 12 forming terminals are arranged on the emitting side (right side in the drawing). The collimator 10 on one side is connected to the other end of the rare earth-doped optical fiber F, and the collimator 1 on the other side is connected.
2 is in a facing positional relationship. From the lower collimator 11 located on the same side as the collimator 10, the wavelength of 1480n
m excitation light is emitted. A long wave transmission filter 13, which is a wavelength division multiplexing filter, is arranged near the exit side of the collimator 10. The long-wave transmission filter 13 includes the signal light emitted from one collimator 10 and the other collimator 1.
1 is a filter for multiplexing and demultiplexing with the excitation light emitted from No. 1 at each wavelength. In other words, the long wave transmission filter 1
3 is a long wavelength emitted from the collimator 10
It has a function of transmitting the 550 nm signal light and reflecting the 1480 nm excitation light of a short wavelength emitted from the collimator 11 to the collimator 10 side and returning it to the rare earth-doped optical fiber F. An optical isolator 8 is arranged between the long wave transmission filter 13 and the collimator 12. Optical isolator 8
In this example, a polarization-independent optical isolator is used. A beam splitter 14 as a separating means is arranged between the optical isolator 8 and the collimator 12 on the emission side. As this beam splitter, a non-polarization beam splitter is used. About 99% of the signal light output from the optical isolator 8 is transmitted and about 1% is reflected,
The light is output to the photodiode 15, which is a light receiving device below. The photodiode 15 is electrically connected to an auto power controller for keeping the output of the signal light output from the collimator 12 always constant and automatically. The optical isolator 8, the collimators 11 to 12, the long-wave transmission filter 13, the beam splitter 14, and the photodiode 15 are package containers P.
Incorporated into 2. Since the post-stage module B for optical amplifier has the configuration of the above example, the 1480 nm excitation light output from the collimator 11 is reflected to the collimator 10 side via the long wave transmission filter 13 and propagates to the rare earth-doped optical fiber F. Then, the signal light of 1550 nm is amplified, is incident on the optical isolator 8, is further emitted from the optical isolator, and is separated into two directions by the beam splitter 14. On the other hand, about 99% of the signal light passes through the beam splitter 14. The light is transmitted, condensed by the collimator 12 on the output side, and output. On the other hand, about 1% of the signal light is output to the auto power controller via the photodiode 15.

[0009]

According to the present invention, since the optical amplifier / combiner, which is an optical passive component, the light receiving device, and the optical isolator are integrated into a front-stage module for an optical amplifier, the optical multiplexer, which is an optical passive component, is also used. Since it is a post-module for an optical amplifier that integrates a demultiplexer, an optical isolator, a light receiving device, and an optical branching / coupling device, the fusion points between components can be reduced compared to the conventional example, and fusion loss can be reduced. . According to the present invention, the pre-stage module and the post-stage module for the optical amplifier can have a smaller number of terminals, for example, collimators, as compared with the conventional example, and can reduce the number of parts as a whole, so that it can be made compact.

[Brief description of drawings]

FIG. 1 is a schematic view showing an embodiment of the present invention.

FIG. 2 is a configuration diagram showing one embodiment of the present invention.

FIG. 3 is a schematic view showing a conventional example.

FIG. 4 is a configuration diagram showing a conventional example.

[Explanation of symbols]

 A front-stage module for optical amplifier B rear-stage module for optical amplifier F rare earth-doped optical fiber 1 optical branch coupler 2 optical isolator 3 collimator (terminal) 4 collimator (terminal) 5 beam splitter (separating means) 6 photodiode (light receiving device) 7 Optical multiplexer / demultiplexer 8 Optical isolator 9 Optical branching / coupling device 10 Collimator (terminal) 11 Collimator (terminal) 12 Collimator (terminal) 13 Long-wave transmission filter (wavelength division multiplex filter) 14 Beam splitter (separation means) 15 Photodiode (light reception) device)

Claims (8)

[Claims] 1. A pre-stage module for an optical amplifier, wherein an optical branching / coupling device, an optical isolator, and a light receiving device are integrated. 2. A terminal arranged on each of an incident side and an emitting side of signal light, a separating means arranged between both terminals, and a signal light from the terminal on the incident side via the separating means. A light receiving device for receiving a part of the light and an optical isolator arranged between the separating means and the output side terminal, respectively, and the output side terminal is connected to a rare earth-doped optical fiber. A front-end module for optical amplifiers that is characterized by 3. A collimator disposed on each of an incident side and an emission side of signal light, a beam splitter disposed between both collimators, and a signal light from the incident side collimator via the beam splitter. The light receiving device for receiving a part of the light is integrated with the optical isolator arranged between the beam splitter and the collimator on the output side, and the collimator on the output side is connected to the rare earth-doped optical fiber. A front-end module for an optical amplifier, which is characterized in that 4. The optical amplifier according to claim 3, wherein the beam splitter is a non-polarization beam splitter, the light receiving device is a photodiode, and the optical isolator is a polarization-independent optical isolator. Front stage module. 5. A post-stage module for an optical amplifier, characterized in that an optical multiplexer / demultiplexer, an optical isolator, a light receiving device and an optical branching / coupling device are integrated. 6. A terminal which is arranged on each of the signal light incident sides, one of which is connected to a rare-earth-doped optical fiber, the other of which is a terminal for pumping light, and the signal light which is emitted from the one terminal. And a wavelength division multiplexing filter for multiplexing and demultiplexing the excitation light emitted from the other terminal with respective wavelengths, an optical isolator on which the signal light passing through the wavelength division multiplexing filter is incident, and a side opposite to the terminal Which is disposed on the output side of the signal light and outputs the signal light, separation means disposed between the output side terminal and the optical isolator, and the above-mentioned light through the separation means. A post-stage module for an optical amplifier, which is integrated with a light receiving device that receives a part of the signal light from the isolator. 7. A collimator, which is arranged on each of the signal light incident sides, one of which is connected to a rare-earth-doped optical fiber, the other of which is a pump light collimator, and the signal light emitted from the one collimator. And a wavelength division multiplexing filter for multiplexing and demultiplexing the excitation light emitted from the other collimator with respective wavelengths, an optical isolator on which the signal light passing through this wavelength division multiplexing filter is incident, and the side opposite to the collimator The collimator which is arranged on the output side of the signal light and outputs the signal light, the beam splitter which is arranged between the collimator on the output side and the optical isolator, and the above-mentioned light beam through this beam splitter. A post-stage module for an optical amplifier, which is integrated with a light-receiving device that receives a part of the signal light from the isolator. Lumpur. 8. The optical isolator according to claim 7, which is a polarization-independent optical isolator, the beam splitter is a non-polarization beam splitter, the light receiving device is a photodiode, and the wavelength division multiplexing filter is a long-wave transmission filter. A post-stage module for an optical amplifier, which is characterized by being present.