JPH06120598A - Two-wavelength pumping optical fiber amplifier - Google Patents

Abstract

PURPOSE:To increase the amplification efficienty by optical pumping by connecting to a second WDM coupler the optical pumping means of a light having a wavelength different from that of a first pump light, thereby forming an Er dope optical fiber section in which the pump lights of both wavelengths can be superposed and pumped. CONSTITUTION:A pumping light amplifier is constructed such that the Er dope optical fiber of it is divided into two, a first section B-1 and a second section B-2, a first pump light having a wavelength closely resembling the wavelength of an input signal light 5-1 is pumped to the input end side of the first section through a first WDM coupler 2-1, and the first section and the second section are connected through a second WDM coupler 2-2, through which a second pump light having a wavelength extremely different from that of the first pump light can be pumped. This allows the residual pump light in a first optical fiber 3-1 to be again input to a second optical fiber 3-2, whereby the amplification efficiency can be increased.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a dual wavelength pumped optical fiber amplifier. More specifically, the present invention relates to an optical fiber amplifier capable of superposing and pumping two kinds of pumping lights having different wavelengths by using an ordinary WDM coupler.

[0002]

2. Description of the Related Art In using an optical fiber amplifier, when it is desired to expand the linear operation region with a large output, a corresponding optical pump power is injected from the midpoint of an Er-doped optical fiber to expand the dynamic range. Methods such as increasing the output have been devised. In this case, the pumping wavelength used is usually one wavelength, and it is necessary to use a Y-multiplexing coupler as the optical fiber coupler at the midpoint. However, the above-mentioned conventional techniques have problems that it is difficult to manufacture a Y-multiplexing coupler and that the amplification efficiency is unsatisfactory.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a two-wavelength pumping optical fiber amplifier which has high amplification efficiency by optical pumping, has a wide range of use, and is easy to manufacture.

[0004]

A two-wavelength pumping optical fiber amplifier according to the present invention comprises an optical signal input end, an optical signal output end, and an Er-doped optical fiber part arranged between the both ends. In an optical fiber amplifier including, the Er-doped optical fiber section is divided into a first section and a second section, and an input side terminal of the first section is connected to the optical signal input end section through a first WDM coupler. And the first
The output terminal of the section is connected to the input terminal of the second section via a second WDM coupler, and the output terminal of the second section is connected to the optical signal output end, An optical pumping means for the first pump light having a wavelength close to the wavelength of the input signal light is connected to the first WDM coupler, and the second WDM coupler is different from the wavelength of the first pump light. An optical pumping means for the light having a wavelength is connected, thereby forming an Er-doped optical fiber section capable of superposing and pumping the pump light of both wavelengths.

[0005]

In the pumping optical amplifier of the present invention, the Er-doped optical fiber is divided into a first section and a second section,
The first pump light having a wavelength close to the wavelength of the input signal light is pumped to the input end side of the first section through the first WDM coupler, and the first section and the second section are connected to the second WD.
A second pump light having a wavelength remarkably different from the wavelength of the first pump light is connected through the M coupler, and the second WDM coupler is used to pump the second pump light. It is possible to pump the second section of the doped optical fiber with both wavelengths of the first and second pump light. The wavelength of the input and output signal light is generally 1.55 μm, and the wavelength of the first pump light used in the amplifier of the present invention is close to 1.55 μm and is in the range of 1.45 to 1.49 μm. Preferably, the wavelength of the second pump light is clearly different from the wavelengths of the input signal light and the first pump light, and is generally preferably in the range of 0.97 to 0.99 μm.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The dual wavelength pumped optical fiber of the present invention will be described with reference to the embodiment shown in FIG. In FIG. 1, a two-wavelength pumping optical fiber amplifier has a wavelength of 1.5.
An optical signal input end A having a 5 μm optical filter and an isolator 1-1, an optical signal output end C having an optical filter and an isolator 1-2 similar to the above, and both ends 1-1 and 1-2. And an Er-doped optical fiber portion B disposed between the two.

The Er-doped optical fiber portion B has a first section B-
The input terminal side terminal of the first optical fiber 3-1 constituting the first section B-1 is input into the optical signal via the first WDM coupler 2-1. Edge A
Is connected to the optical filter / isolator 1-1. The output end side terminal of the first optical fiber 3-1 is the second WD.
A second section that constitutes a second section B-2 via the M coupler 2-2.
It is connected to the input end side terminal of the optical fiber 3-2. The output end side terminal of the second optical fiber 3-2 is an optical signal output end C.
Is connected to the optical filter / isolator 1-2.

A first optical pumping means 4-1 is connected to the first WDM coupler 2-1, and the first pump light is pumped into the first optical fiber 3-1 via the first WDM coupler and input. The amplified signal light 5-1 is amplified.

A second optical pumping means 4-2 is connected to the second WDM coupler 2-2, and the second pump light is supplied to the second optical pumping means 4-2.
The second optical fiber 3-through the second WDM coupler 2-2.
2 to amplify the light in the second optical fiber 3-2.

The light amplified by the first and second pump lights as described above is output as the output signal light 5-2 through the second optical filter and the isolator.

An example of amplification operation by the optical fiber amplifier of the present invention will be described. As the first WDM coupler 2-1, optical ones having wavelengths of 1.55 μm and 1.48 μm are used, and as the second WDM coupler 2-2, wavelength of 1.55 μm is used.
(For 1.48 μm included) and for 0.98 μm light are used. The first optical pumping means 4-1 has a wavelength of 1.
It pumps light of 48 μm, and the second optical pumping means 4-2 pumps light of wavelength 0.98 μm.

Input signal light having a wavelength of 1.55 μm is input to the optical signal input end A. This input signal light is sent to the Er-doped optical fiber part B through the optical filter / isolator 1-1. First pump light (wavelength 1.48 μm) pumped from the first optical pumping means 4-1.
Passes through the first WDM coupler 2-1 and the first optical fiber 3
-1 is pumped, and the input signal light having a wavelength of 1.55 μm is amplified.

This amplified input signal light (wavelength 1.55
μm) is sent to the second optical fiber 3-2 through the second WDM coupler 2-2. Also, the first optical fiber 3
Wavelength of residual pump light not absorbed by -1 1.4
Since 8 μm is close to the wavelength of signal light of 1.55 μm, it can be input to the second optical fiber 3-2 through the second WDM coupler 2-2.

Pump light having a wavelength of 0.98 μm is pumped from the second optical pumping means 4-2 to the second optical fiber 3-2 through the second WDM coupler 2-2, and the second optical fiber 3-2 is pumped. The input signal light that passes is amplified. The amplified signal light (wavelength 1.55 μm) passes through the second optical filter / isolator 1-2 (for light having wavelength 1.55 μm) and is output from the amplifier as output signal light 5-2.

In the amplifier of the present invention as described above, the first
The remaining pump light of the optical fiber 3-1 is supplied to the second optical fiber 3
-2 can be input again to further amplify the input signal light.

The optical fiber amplifier of the present invention can also be used for reverse pumping.

[0017]

The dual-wavelength pumping optical fiber amplifier of the present invention divides the optical fiber portion into the first and second sections, so that a normal WDM coupler can be used without using a Y-multiplexing coupler which is difficult to manufacture. It becomes possible to re-input the pump light remaining in the first optical fiber into the second optical fiber by using a coupler, thereby improving the amplification efficiency with respect to the input signal light, and using the optical fiber amplifier having various characteristics. It enables design and is extremely useful in practice.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a configuration of an example of a dual wavelength pumping optical fiber amplifier of the present invention.

[Explanation of symbols]

 A ... Optical signal input end B ... Er-doped optical fiber portion C ... Optical signal output end 1-1, 1-2 ... Optical filter / isolator 2-1, 2-2 ... WDM coupler 3-1, 3-2 ... optical fibers 4-1 and 4-2 ... optical pumping means 5-1 ... input signal light 5-2 ... output signal light

Claims (1)

[Claims] 1. An optical signal input end, an optical signal output end,
An optical fiber amplifier including an Er-doped optical fiber section arranged between the both ends, wherein the Er-doped optical fiber section is divided into a first section and a second section, and an input side terminal of the first section is provided. Is the first WD
Is connected to the optical signal input end via an M coupler, the output side terminal of the first section is connected to the input side terminal of the second section via a second WDM coupler,
The output side terminal of the second section is connected to the optical signal output end, and the first WDM coupler is connected to an optical pumping means for the first pump light having a wavelength close to the wavelength of the input signal light. And in the second WDM coupler,
An optical pumping means for the second pump light having a wavelength different from the wavelength of the first pump light is connected, thereby forming an Er-doped optical fiber section capable of superposing and pumping the pump light of both wavelengths. A dual-wavelength pumping optical fiber amplifier.