JP2986580B2 - Optical fiber amplifier and manufacturing method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber amplifier using a rare earth doped fiber and a method for manufacturing the same . An optical amplifier that directly amplifies an optical signal as it is without converting the optical signal into an electrical signal is practically bit-rate-free, has a large capacity, and is capable of multi-channel batch amplification. It is being actively studied by various research institutions as one of the key devices for future optical communication systems.

As one form of this type of optical amplifier, an optical fiber in which a core is mainly doped with a rare earth element or ions (Er, Nd, Yb, etc.) (referred to as a “rare earth doped fiber” in the present specification) is used. There are optical fiber amplifiers.

An optical fiber amplifier has excellent features such as a large gain, no dependency of gain on polarization, low noise, and a small connection loss with a fiber for a transmission line. Optimization of the above configuration is sought.

[0004]

2. Description of the Related Art FIG. 5 is a diagram showing a general configuration of a conventional optical fiber amplifier. The optical fiber amplifier includes an excitation light source 2, an optical multiplexer 4 for multiplexing the input signal light with the excitation light from the excitation light source 2, and a rare-earth doped fiber to which the signal light and the excitation light from the optical multiplexer 4 are input. 6 is provided. 8 is an input port for inputting signal light, 10 and 12 are optical isolators provided on the input side and output side of the rare earth doped fiber 6, 14 is an output port for outputting amplified signal light, and 16 is a rare earth doped fiber. Reference numeral 6 denotes a reel to be wound.

[0005]

In the rare earth doped fiber, if the doping concentration of the rare earth element is too high, the gain is reduced by the concentration quenching phenomenon, so that there is an optimum value of the doping concentration.

For example, when the rare earth element is Er (erbium)
, The optimum doping concentration is several hundred ppm or less. In this case, the length of the rare-earth-doped fiber required to obtain a sufficient gain becomes as long as several tens of meters to several hundreds of meters, and when configuring an optical fiber amplifier using this rare-earth-doped fiber, the rare-earth-doped fiber is large. There has been a problem that the optical fiber amplifier occupies a large space and becomes large.

Since the loss of the rare-earth-doped fiber increases when the curvature is too small, specifically, when the width of the reel is set to about 20 mm in accordance with the height of other parts,
Reel inner diameter is about 60mm and reel outer diameter is 100mm ~ 200mm
Therefore, it is difficult to reduce the size of the optical fiber amplifier.

The present invention has been made in view of such circumstances, and an optical fiber amplifier suitable for miniaturization and its manufacture.
It is intended to provide a fabrication method .

[0009]

SUMMARY OF THE INVENTION An optical fiber amplifier according to the present invention created to solve the above-mentioned technical problems,
An optical fiber amplifier comprising: a pump light source, an optical multiplexer for multiplexing the input signal light with the pump light from the pump light source, and a rare earth doped fiber to which the signal light and the pump light from the optical multiplexer are input. The wound rare earth doped fiber is arranged on the outer periphery of another component. Yo
More specifically, a plurality of V-shaped cuts around the periphery at predetermined intervals
Rare-earth element wound on a circular reel
The fiber is connected to the V-shaped notch based on the V-shaped cut.
When the adjacent surfaces of the notches contact each other,
Housed in a rectangular reel.
A reel is arranged around the other component. Others of the present invention
According to the aspect of the above, the pump light source and the input signal light are pumped as described above.
An optical multiplexer for multiplexing with the excitation light from the electromotive light source, and the optical multiplexer
-Earth doped phyll to which signal light and pump light from
In a method of manufacturing an optical fiber amplifier having
A plurality of V-shaped cuts are not formed at predetermined intervals in the frame.
Wrap a rare-earth doped fiber around a circular reel
The V-shaped notch deforms the reel into a square shape
And place the rectangular reel around the other components.
Providing a method of manufacturing an optical fiber amplifier
Is done.

[0010]

According to the structure of the present invention, since the wound rare earth doped fiber is arranged on the outer periphery of another component,
The capacity of the apparatus can be effectively used, and the size of the optical fiber amplifier can be reduced. Further, the increase in loss due to the small curvature curvature of the rare-earth doped fiber hardly occurs. Furthermore, since reels of a specific shape are used,
Of the rare-earth doped fiber on the reel
Optical fiber amplifier compatible with workability and suitable for miniaturization
Can be easily manufactured.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of an optical fiber amplifier showing an embodiment of the present invention. Parts substantially the same as those in FIG. 5 showing the prior art are denoted by the same reference numerals.

Reference numeral 2 denotes an excitation light source composed of a semiconductor laser, and this excitation light source 2 outputs excitation light having a wavelength of 1.48 μm. The signal light having a wavelength of 1.55 μm input from the input port 8 using an optical connector or the like is input to the optical multiplexer 4 together with the excitation light from the excitation light source 2, where the signal light and the excitation light are multiplexed. You.

The signal light and the pumping light from the optical multiplexer 4 enter the rare-earth doped fiber 6 doped with Er via the optical isolator 10, and the signal light and the pumping light are acted on by the action of the doped rare-earth element and the pumping light. Light amplification is performed.

The amplified signal light is supplied to an optical isolator 12
And output from the output port 14 via. Each component is placed on a suitable substrate 18 and optical connections between each component are made by optical fibers.

The rare-earth doped fiber 6 is wound on a reel 20 provided along the outer periphery of a substrate 18 having a rectangular component arrangement surface. The excitation light source 2, the optical multiplexer 4, and the optical isolators 10 and 12 are arranged inside the reel 20.

FIG. 2 is a plan view of the reel 20, and FIG. 3 is a cross-sectional view of the reel 20 taken along line AA. Reel 2
0 has a substantially rectangular shape along the outer periphery of the rectangular substrate 18, and its four corners have an appropriate curvature such that the bending loss of the wound rare earth doped fiber does not increase. The curvature is given.

In the cross section of the reel 20, reference numeral 22 denotes a groove around which the rare-earth-doped fiber 6 is wound. By forming such a groove, the operation of winding the rare-earth-doped fiber 6 around the reel 20 is easy. And the wound rare earth doped fiber is less likely to fall off.

By arranging the rare earth-doped fiber along the outer periphery of the substrate using such a reel, components such as the excitation light source 2 can be arranged inside the rare earth-doped fiber, and the size of the optical fiber amplifier can be reduced. Will be possible.

By the way, when mounted on a rectangular substrate, the shape of the reel is preferably a substantially rectangular shape as described above. However, in order to wind the rare earth doped fiber around the reel, the reel is formed of a ring. A shape is desirable.

Therefore, in another preferred embodiment of the present invention, a reel as shown in FIG. 4 is used. That is,
As shown in FIG. 4A, a reel 26 is used in which a plurality of notches 24 are formed at equal intervals in the circumferential direction on the outer periphery of a ring member made of plastically deformable resin or the like. After winding the rare earth doped fiber to
As shown in FIG. 4B, the reel 26 and the wound rare earth doped fiber are deformed into a substantially rectangular shape.

According to this embodiment, it is possible to achieve both the mountability of the reel on the substrate and the workability of winding the rare-earth doped fiber on the reel.

[0022]

As described above, according to the present invention,
There is an effect that an optical fiber amplifier suitable for miniaturization and a method for manufacturing the same can be provided.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an optical fiber amplifier showing a preferred embodiment of the present invention.

FIG. 2 is a plan view of the reel shown in FIG. 1;

FIG. 3 is a cross-sectional view of the reel shown in FIG. 2, taken along line AA.

FIG. 4 is an explanatory view of a reel according to another preferred embodiment of the present invention.

FIG. 5 is an explanatory diagram of a conventional technique.

[Explanation of symbols]

 2 Excitation light source 4 Optical multiplexer 6 Rare earth doped fiber 20, 26 Reel

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Osamu Oyama 1015 Ueodanaka Nakahara-ku, Kawasaki City, Kanagawa Prefecture Inside Fujitsu Co., Ltd. 56) References JP-A-3-121426 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01S 3/06 H01S 3/02 H01S 3/10 H04B 10/16 H04B 10 / 17

Claims (2)

(57) [Claims] A pumping light source; an optical multiplexer for multiplexing the input signal light with the pumping light from the pumping light source; and a rare-earth doped fiber to which the signal light and the pumping light from the optical multiplexer are input. In the optical fiber amplifier, a plurality of V-shaped cuts are formed around the circumference at predetermined intervals.
-Earth doped fiber wound on a circular reel
Is a V-shaped cut based on the V-shaped cut.
Square shape that becomes straight when adjacent
An optical fiber amplifier housed in a reel having a rectangular shape, wherein the rectangular reel is arranged on the outer periphery of another component. 2. An excitation light source, comprising :
An optical multiplexer for multiplexing with the excitation light from the light source;
Rare-earth doped fiber into which signal light and pump light are input
And a plurality of V-shaped cuts are formed around the periphery at predetermined intervals.
A rare-earth doped fiber is wound around a circular reel, and the reel is changed into a square shape by the V-shaped cut.
And place the square reel around the outer periphery of other components.
And a method for manufacturing an optical fiber amplifier.