JPH06283789A - Light amplifier - Google Patents

Abstract

PURPOSE:To provide a small light amplifier which is easily arranged at the time of incorporating it in a device. CONSTITUTION:A light amplifier is permitted to amplify signal light by inputting the signal light and pumping light into active element doped optical fiber and using the stimulated emission of the active element. The light amplifier is provided with the active element doped fiber 1, which is wound on a loop, an pumping light source 8, a power source circuit 9 for driving the pumping light source 8 and an optical multiplexer/demultiplexer 5 which directs pumping light from the pumping light source 8 to the active element doped fiber. Optical isolators 4, 6 and 7 to be inserted between optical components are arranged on a substrate 13 and are stored in a rectangular container 2 and a heat dissipating plate 14 joined to the substrate 13 is exposed to the external.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical amplifier used in the field of optical communication.

[0002]

2. Description of the Related Art In an optical communication system, amplification of an optical signal attenuated by long-distance transmission is conventionally performed by first converting the optical signal into an electric signal, electrically amplifying the electric signal, and then converting the electric signal again. Is being implemented. However, in such a method, there is a problem in that the relay of multiplex communication, which requires high speed, is limited by itself, and the system becomes complicated. Recently, it is possible to directly transmit an optical signal without converting the optical signal into an electric signal. Optical amplifiers that can amplify are being used. The optical amplifier induces an active element in which a signal light passing through an optical fiber in which an active element such as Er is doped in a core portion of the optical fiber is excited by pumping light incident on the active element-doped optical fiber together with the signal light. It is directly amplified by emission. An optical amplifier using an optical fiber doped with Er as an active element is suitable for optical amplification for 1.55 μm band optical communication and is already in practical use. Further, for optical amplification for 1.3 μm band optical communication, attention is paid to an optical fiber doped with Nd or Pr.

The main components of an optical amplifier are, in addition to an optical fiber doped with an active element, a pumping light source for pumping the active element, a power supply circuit for driving the pumping light source, and a pumping light source. There is an optical multiplexer / demultiplexer for making the pumping light from the optical element incident on the active element-doped fiber, and an optical isolator for removing the reflected light of the pumping light or the signal light. The incident direction of the pumping light to the active element-doped fiber is as follows: frontward pumping that excites the signal light from the incident side to the active element-doped fiber, rearward pumping that pumps from the exit side, and pumping from both the incident side and the exit side. There is bidirectional pumping, which can be used properly according to the purpose of use of the optical amplifier.

The active element-doped fibers used for optical amplifiers have different lengths depending on the active element concentration in the core and the fiber structure.
Various types up to m or more are adopted, and a reel having a diameter of several cm is wound to make the entire optical amplifier compact.

[0005]

Since the optical amplifier includes the optical parts and the electronic parts intricately as described above, it is difficult to dispose the optical amplifier and the size of the optical amplifier tends to increase. In order to reduce the size, for example, in Japanese Patent Laid-Open No. 3-269416, a part or all of the pumping light supply means is arranged in a cylindrical unit as a 1.55 μm band amplification optical amplification repeater. , An erbium-doped fiber is wound around the outer periphery of the unit. However, constructing parts three-dimensionally in a cylindrical unit requires a considerable amount of work. Further, since this optical amplifier has a cylindrical outer shape, there is a problem that it is difficult to dispose the optical amplifier when it is further incorporated into a device.

The present invention has been made in order to solve such a problem, and an object thereof is to provide an optical amplifier which is small in size and easy to dispose when incorporated in a device.

[0007]

An optical amplifier according to the present invention for achieving this object is provided with a signal light from a signal light transmitting fiber 11 and a pumping light source 8 as shown in FIG. 1 corresponding to an embodiment. In the optical amplifier in which the excitation light from the optical element is incident on the active element-doped fiber 1, the signal light is amplified by the stimulated emission light of the active element, and is output to the signal light transmission fiber 12, the active element-doped fiber wound in a loop is used. Between the fiber 1, the excitation light source 8, the drive power supply circuit 9 for the excitation light source 8, the optical multiplexer / demultiplexer 5 for causing the excitation light from the excitation light source 8 to enter the active element-doped fiber 1, and the above-mentioned optical components. The optical isolators 4, 6 and 7 to be inserted into the substrate are arranged on the substrate 13 and housed in a rectangular container, and the heat dissipation plate 14 that is in close contact with the substrate 13 is exposed to the outside.

Similarly, an optical amplifier according to another aspect of the present invention for achieving the above-mentioned object, as shown in FIG. 2 corresponding to the embodiment, comprises a signal light from a signal light transmitting fiber 11 and a pumping light source 8. In the optical amplifier in which the excitation light of (1) is incident on the active element-doped fiber 1, the signal light is amplified by the stimulated emission light of the active element, and is output to the signal light transmission fiber 12, a substantially rectangular loop is formed on the substrate 13. The wound active element-doped fiber 1, the excitation light source 8, the drive power supply circuit 9 for the excitation light source 8, the optical multiplexer / demultiplexer 5 for causing the excitation light from the excitation light source 8 to enter the active element-doped fiber 1, and Optical isolators 4 and 6 inserted between the optical components
7 is arranged, and the heat dissipation plate 14 that is in close contact with the substrate 13 is exposed to the outside.

[0009]

In the optical amplifier of the present invention, since the heat radiating plate 14 exposed to the outside is a square forming one surface of the outer shape of the container, the heat radiating efficiency is good and the operation is stable and the size is small. However, the layout is easy when it is installed in equipment.

[0010]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 shows an embodiment of an optical amplifier to which the present invention is applied. The optical amplifier of the present invention shown in the figure is a backward pumping amplifier, which is inserted in the middle from the signal light transmission fiber 11 on the incident side to the signal light transmission fiber 12 on the emission side, and is made of bakelite. It is assembled on the substrate 13. An optical isolator 4 is connected to the signal light transmission fiber 11 on the incident side, and one end of the active element-doped fiber 1 is further connected. The other end of the active element-doped fiber 1 is connected to the input port of the optical multiplexer / demultiplexer 5. One of the ports branched to the signal light output side of the optical multiplexer / demultiplexer 5 is connected to the signal light transmission fiber 12 on the emission side via the isolator 7, and the other port is connected to the pumping light source 8 via the isolator 6. Connected. The excitation light source 8 is connected to the drive power supply circuit 9. The drive power supply circuit 9 is connected to an external commercial power supply by a cord 15. Each of the above components assembled on the substrate 13 is housed in the rectangular metal container 2. A metal heat dissipation plate 14 is in close contact with the opposite surface of the substrate 13 to form one surface of a rectangular outer wall.

Since the optical amplifier in this embodiment is for the 1.55 μm band, Er is used as the active element in the active element-doped fiber. The total length of the active element-doped fiber 1 is 30 m in this example.

The signal light incident from the signal light transmission fiber 11 on the incident side enters the active element-doped fiber 1 via the isolator 4. The pumping light from the pumping light source 8 is incident on the other end of the active element-doped fiber 1 by the coupling function of the optical multiplexer / demultiplexer 5. While passing through the active element-doped fiber 1, the signal light is amplified by the stimulated emission of the active element excited by the excitation light, passes through the optical multiplexer / demultiplexer 5, and passes through the isolator 7 to the signal light transmission fiber 12 on the emission side. It goes out to.

FIG. 2 shows another embodiment of the optical amplifier to which the present invention is applied. The optical amplifier of the present invention shown in the same figure is a forward pumping amplifier, and is inserted in the middle from the signal light transmission fiber 11 on the incident side to the signal light transmission fiber 12 on the emission side. It is assembled on the substrate 13. The isolator 4 is connected to the signal light transmission fiber 11 on the incident side, and is further connected to the first input port of the optical multiplexer / demultiplexer 5. The second input port of the optical multiplexer / demultiplexer 5 is connected to the excitation light source 8 via the isolator 6. The excitation light source 8 is connected to the drive power supply circuit 9. The drive power supply circuit 9 is connected to an external commercial power supply by a cord 15. One end of the active element-doped fiber 1 is connected to the output port of the optical multiplexer / demultiplexer 5. Active element doped fiber 1
Is placed in an aluminum tube 3 and wound along the outer periphery of the substrate 13 in a substantially rectangular loop shape for a required length. The other end of the active element-doped fiber 1 is connected to the signal light transmission fiber 12 on the emission side via the isolator 7. The above-mentioned components assembled on the substrate 13 are arranged inside the substantially rectangular shape of the aluminum tube 3 into which the active element-doped fiber 1 is inserted and wound up. A metal heat sink 14 is provided on the opposite surface of the substrate 13.
Adhere to each other and form one side of the rectangular outer wall.

[0014]

As described in detail above, the optical amplifier of the present invention has a rectangular shape in which the heat dissipation plate 14 forms one surface of the outer shape of the container. Therefore, the heat dissipation efficiency is good, the operation is stable, and the size is small. However, it is easy to arrange when it is installed in equipment.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment of an optical amplifier to which the present invention is applied.

FIG. 2 is a perspective view of another embodiment of the optical amplifier to which the present invention is applied.

[Explanation of symbols]

1 is an active element doped fiber, 2 is a container, 3 is an aluminum tube, 4/6 and 7 are optical isolators, 5 is an optical multiplexer / demultiplexer, 8 is a pumping light source, 9 is a drive power supply circuit, and 11.1.1
Reference numeral 2 is a signal light transmission fiber, 13 is a substrate, 14 is a heat sink, and 15 is a code.

Claims (2)

[Claims] 1. An optical amplifier for injecting signal light and excitation light into an optical fiber doped with an active element, and utilizing stimulated emission light of the active element to amplify the signal light. Element-doped fiber, pumping light source, power supply circuit for driving the pumping light source, optical multiplexer / demultiplexer for making pumping light from the pumping light source incident on the active element-doped fiber, and inserted between the optical components. The optical isolator is placed on the substrate and housed in a rectangular container,
An optical amplifier characterized in that a heat dissipation plate in close contact with the substrate is exposed to the outside. 2. An optical amplifier for injecting signal light and excitation light into an optical fiber doped with an active element, and utilizing the stimulated emission light of the active element to amplify the signal light. Inside the loop of the active element-doped fiber wound around the loop, a pumping light source, a power supply circuit for driving the pumping light source, and an optical multiplexer / demultiplexer for allowing pumping light from the pumping light source to enter the active element-doped fiber And an optical isolator inserted between the optical components, and a heat dissipation plate in close contact with the substrate is exposed to the outside.