JPH1187815A - Multi-wavelength light source - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multi-wavelength light source for simultaneously outputting the light of many wavelengths in a simple structure. SOLUTION: One end of a light amplification fiber 10 to which Er is added is connected to the multiplex port of a wavelength demultiplexing element 12, and the other end of the light amplification fiber 10 is connected to a reflection element 16 for reflecting the light of 1.5 μm band but transmitting the excitation light (0.98 μm band or 1.48 μm band) of an excitation light source 14. The wavelength demultiplexing element 12 is an element, an array waveguide diffraction grating, for instance, for individually demultiplexing light inputted to the multiplex port to respective wavelengths λ1-λn, outputting it from individual wavelength ports corresponding to the respective wavelengths, synthesizing the light of the respective wavelengths λ1-λn inputted to the respective individual wavelength ports, and outputting it from the multiplex port. To the respective individual wavelength ports of the wavelength demultiplexing element 12, the reflection elements 18-1-18-n for selectively reflecting the corresponding wavelengths λ1-λn are connected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a multi-wavelength light source, and more particularly, to a multi-wavelength light source that can be used in a wavelength division multiplexing optical transmission system.

[0002]

2. Description of the Related Art A conventional multi-wavelength light source, which outputs a plurality of wavelengths at narrow wavelength intervals and is suitable for a wavelength division multiplexing system, is basically a juxtaposition of semiconductor lasers whose oscillation wavelength is precisely controlled by temperature control. Configuration. That is, it is necessary to prepare as many semiconductor lasers as the number of wavelengths to be wavelength division multiplexed.

[0003] With the improvement in semiconductor manufacturing technology, it is possible to integrally manufacture semiconductor lasers that oscillate at different wavelengths from each other, and to arrange a plurality of semiconductor lasers on one semiconductor substrate in close proximity or closely. However, there is no change in that semiconductor lasers for the number of wavelengths to be wavelength division multiplexed must be prepared.

[0004]

In the prior art, there is a problem that the size of the device increases in proportion to the number of wavelengths and the cost increases.

Further, in order to obtain a required wavelength, a complicated operation of selecting a semiconductor laser having an oscillation wavelength close to a desired wavelength from a plurality of semiconductor lasers and matching the oscillation wavelength to the desired wavelength by temperature control is further performed. And it was extremely difficult to reduce the cost. Since a large number of active elements are used, there is also a problem in reliability.

An object of the present invention is to solve such a problem and to provide a multi-wavelength light source which simultaneously outputs a large number of wavelengths with a simple structure.

Another object of the present invention is to provide a more reliable multi-wavelength light source.

Another object of the present invention is to provide a multi-wavelength light source that does not increase in size even when the number of wavelengths increases.

Another object of the present invention is to provide a multi-wavelength light source that can be manufactured at lower cost.

Another object of the present invention is to provide a multi-wavelength light source that outputs light of a desired wavelength stably for a long period of time.

[0011]

According to the present invention, there is provided a multi-wavelength light source, comprising: an excitation light source for generating excitation light; an optical amplification means which is excited by the excitation light to amplify light in a predetermined output wavelength band; A first reflection member that is connected between one end of the optical amplification unit and the excitation light source, transmits the excitation light from the excitation light source to the optical amplification unit, but reflects the predetermined output wavelength band; Connected to the other end of the optical amplifying means, separates the light from the optical amplifying means into a plurality of lights, outputs the light from the individual wavelength port, multiplexes the light input to the individual wavelength port, and outputs the combined light to the optical amplifying means A second multiplexer / demultiplexer connected to the individual wavelength port of the multiplexer / demultiplexer and reflecting light from the individual wavelength port to return to the individual wavelength port.
And at least one of the multiplexing / demultiplexing means and the second reflecting member has a wavelength characteristic corresponding to a desired output wavelength.

The output wavelength is determined by the multiplexing / demultiplexing means and the second reflecting member, and the optical amplifying means only needs to amplify light in the output wavelength band. Wavelength light can be obtained simultaneously.

An increase in the number of wavelengths can be handled by the multiplexing / demultiplexing means and the second reflecting member, so that an increase in the number of wavelengths does not increase the size of the apparatus.

Since it can be realized with a simple structure and an inexpensive element, the manufacturing cost can be greatly reduced. Since the structure is simple, stable operation can be expected for a long time, and high reliability is achieved.

The light amplifying means is composed of, for example, a light emitting medium having light emitting means which emits light of the predetermined output wavelength band when excited by the excitation light. A multi-wavelength light source in the 1.5 μm band can be realized by using Er as the light emitting means and using one of the laser light sources in the 1.48 μm band and the 0.98 μm band as the excitation light source. Further, by using a fluoride fiber doped with Pr as the light emitting medium and a laser light source in the 1.02 μm band as the excitation light source, a multi-wavelength light source in the 1.3 μm band can be realized.

The optical amplification means is excited by the excitation light,
A light emitting medium comprising: a first light emitting unit that emits light at a wavelength different from the excitation light; and a second light emitting unit that emits light in a predetermined output wavelength band when excited by light generated by the first light emitting unit. And a third reflecting member disposed on both sides of the light emitting medium and reflecting light generated by the first light emitting means, but transmitting light in a predetermined output wavelength band. Thereby, the first
The output light of the light emitting means is confined in the light emitting medium, whereby the second light emitting means can be strongly excited. As a result,
Very high intensity light can be generated in the second light emitting means, and a high intensity multi-wavelength light source can be realized.

The light emitting medium is a fluoride fiber doped with Er and Tm, the third reflecting member is a reflecting member that reflects the 1.48 μm band and transmits the 1.5 μm band, and the excitation light source is a 1.06 μm laser. By using the light source, a high intensity multi-wavelength light source in the 1.5 μm band can be realized.

Further, the light emitting medium is a fluoride fiber doped with Pr and Yb, the third reflecting member is a reflecting member that reflects the band of 1.02 μm and transmits the band of 1.3 μm, and the excitation light source is 0.98 μm. 1.3 band laser light source
A high intensity multi-wavelength light source in the μm band can be realized.

The multiplexing / demultiplexing means separates the light from the light emitting means into a plurality of the output wavelengths and outputs the light from the individual wavelength port, and multiplexes the light input to the individual wavelength port to provide the light to the light emitting means. By using the wavelength division multiplexing / demultiplexing means for outputting, a plurality of wavelengths at a predetermined wavelength interval suitable for the wavelength division multiplexing optical communication system can be easily obtained.

By using fiber gratings for the first and second reflection means, the coupling efficiency of input / output light is improved and the manufacture is facilitated. Furthermore, there is an advantage that the output wavelength can be easily determined and output light in a narrow band can be easily obtained.

[0021]

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

FIG. 1 is a schematic block diagram of a first embodiment of the present invention. In the embodiment shown in FIG. 1, laser beams of a plurality of wavelengths λ1 to λn in a 1.5 μm band suitable for a wavelength division multiplexing optical communication system in a 1.5 μm band are simultaneously output.

10 is 1.5 including wavelengths λ1 to λn.
An optical amplification fiber (e.g., an Er-doped optical fiber) doped with a light emitting element that emits light in the μm band, 12 separates the light input to the multiplexing port into individual wave lengths λ1 to λn,
Output from individual wavelength ports corresponding to each wavelength,
It is a wavelength division multiplexing / demultiplexing element (for example, an arrayed waveguide diffraction grating or a blazed diffraction grating) that multiplexes light of each wavelength λ1 to λn input to each individual wavelength port and outputs the multiplexed port.

Reference numeral 14 denotes an excitation light source for generating excitation light (wavelength λp) for exciting the light emitting element added to the optical amplification fiber 10. The excitation light source 14 is, for example, a semiconductor laser that oscillates in a 0.98 μm band or a 1.48 μm band.

Reference numeral 16 denotes a reflection element which reflects 100% of the wavelengths λ1 to λn but transmits the excitation light.
Are reflecting elements that reflect almost 100% of the wavelengths λ1 to λn, respectively.

One end of the optical amplification fiber 10 is connected to a multiplexing port of the wavelength multiplexing / demultiplexing element 12, and the other end of the optical amplification fiber 10 is connected to a reflection element 16. Reflective element 16
From the opposite side, the excitation light from the excitation light source 14
The optical fiber 6 is supplied to the optical amplification fiber 10 via the optical fiber 6. Reflecting elements 18-1 to 18-n that selectively reflect the corresponding wavelengths λ1 to λn are connected to the individual wavelength ports of the wavelength multiplexing / demultiplexing element 12, respectively.

The operation of this embodiment will be described. Excitation light source 14
The excitation light output from the optical amplifier 10 passes through the reflection element 16 and enters the optical amplification fiber 10. The reflection element 16 is 0.98 μm
Since the band or the 1.48 μm band is set to transmit almost 100%, the pumping light output from the pumping light source 14 enters the optical amplification fiber 10 with almost no loss.

Excitation light entering the optical amplification fiber 10 excites a light emitting element in the optical amplification fiber 10 to 1.5 μm
The band emits light. The light in the 1.5 μm band generated by the light emitting element added to the optical amplification fiber 10 propagates toward the reflection element 16 and the wavelength multiplexing / demultiplexing element 12. Reflective element 1
The light in the 1.5 μm band directed to 6 is reflected almost 100% by the reflection element 16 and reenters the optical amplification fiber 10.

On the other hand, the 1.5 μm band light incident on the wavelength division multiplexing / demultiplexing element 12 is separated into wavelengths λ1 to λn by the wavelength division multiplexing / demultiplexing element 12 and output from the individual wavelength ports. The lights of the respective wavelengths λ1 to λn output from the individual wavelength ports of the wavelength multiplexing / demultiplexing element 12 are reflected by the reflection elements 18-1 to 18-n, respectively, input to the same individual wavelength port, and multiplexed again. Is done. The light multiplexed again by the wavelength multiplexing / demultiplexing element 12 is
0, where the light is amplified, reaches the reflection element 16, and is reflected by the reflection element 16.

As described above, of the 1.5 μm band light generated by the light emitting element added to the optical amplification fiber 10, the wavelength multiplexing / demultiplexing element 12 and the reflection elements 18-1 to 18-n
The light components of wavelengths λ1 to λn, which are separated and reflected by the laser, make a round trip between the reflection element 16 and the reflection elements 18-1 to 18-n, and finally the laser oscillation due to the stimulated emission in the optical amplification fiber 10. Leads to. Of course, when the laser oscillation output is not required, it is not necessary to cause the laser oscillation. Many wavelengths λ1 to λ are generated by one optical amplification fiber 10.
Since n can be amplified collectively and temperature control for strictly controlling the wavelength is not required, the configuration can be simplified and the device can be manufactured at low cost.

The reflectance of the reflection elements 18-1 to 18-n is set to 1
By setting it to be less than 00%, laser oscillation light of each wavelength λ1 to λn is transmitted through the reflective elements 18-1 to 18-n and output to the outside. That is, laser oscillation light of each wavelength λ1 to λn can be obtained individually.

The same structure as that of the embodiment shown in FIG.
An m-band multi-wavelength light source can be realized. For this purpose, the optical amplification fiber 10 is a Pr-doped fluoride fiber, and the excitation light source 14 is a 1.02 μm band semiconductor laser. Of course,
The reflective element 16 transmits the 1.02 μm band, but has a 1.3 band.
The wavelength multiplexing / demultiplexing element 12 is an element that wavelength-separates and multiplexes the desired wavelengths λ1 to λn of the 1.3 μm band, and the reflecting elements 18-1 to 18-n.
Is an element that reflects desired wavelengths λ1 to λn in the 1.3 μm band.

Next, a description will be given of a second embodiment of the present invention in which the output is increased. FIG. 2 shows a schematic block diagram of the configuration. 20
Is an optical amplification fiber doped with Er and Tm as light emitting elements, and 22a and 22b are emission wavelength bands of Tm,
, Specifically, 1.47 μm band and / or 1.48 μm band light (hereinafter simply referred to as 1.48 μm band).
Expressed as μm band light. ), But reflects the 1.5 μm band light.
Wavelength division multiplexing / demultiplexing element having the same function as that of
An excitation light source 28 that oscillates laser light in the band, a reflection element 28 that transmits 1.06 μm band light but reflects 100% of 1.5 μm band light, and 30-1 to 30-n have wavelengths λ1 to λn, respectively.
Is a reflecting element that reflects almost 100% of the light.

The output of the excitation light source 26 is connected to one end of the optical amplification fiber 20 via the reflection element 28 and the reflection element 22a. The other end of the optical amplification fiber 20 is
To the multiplexing port of the wavelength division multiplexing / demultiplexing element 24. The individual wavelength ports of the wavelength multiplexing / demultiplexing element 24 include:
Reflecting elements 30-1 to 30 that reflect corresponding wavelengths λ1 to λn
30-n are connected.

The operation of the embodiment shown in FIG. 2 will be described. The 1.06 μm-band excitation light output from the excitation light source 26 passes through the reflection element 28 and the reflection element 22a and
Incident at 0. The reflection elements 28 and 22a are 1.06 μm
Since the band light is set to transmit substantially 100%, the pump light output from the pump light source 26 enters the optical amplification fiber 20 with almost no loss.

The excitation light entering the optical amplification fiber 20 excites the light emitting element Tm in the optical amplification fiber 20 to 1.4.
Light is emitted in the 7 μm band and the 1.48 μm band. The 1.47 μm band light or 1.48 μm band light generated here is reflected by the reflection elements 22a and 22b, and is reflected by the reflection elements 22a and 22b.
During 22b, ie, mainly confined within the optical amplification fiber 20, it leads to having a very high light intensity. The high-intensity 1.48 μm band light excites another light emitting element Er of the optical amplification fiber 20 to emit light in the 1.5 μm band. The generated 1.5 μm band light is reflected by the reflection elements 22 a and 22.
b is transmitted with almost no loss, and propagates toward the reflection element 28 and the wavelength division multiplexing / demultiplexing element 24. The 1.5 μm band light directed to the reflection element 28 is almost 100% by the reflection element 28.
The light is reflected and enters the optical amplification fiber 20 again.

On the other hand, the 1.5 μm band light incident on the wavelength multiplexing / demultiplexing element 24 is wavelength-separated by the wavelength multiplexing / demultiplexing element 24 into each of the wavelengths λ1 to λn and output from the individual wavelength port. The lights of the respective wavelengths λ1 to λn output from the individual wavelength ports of the wavelength multiplexing / demultiplexing element 24 are reflected by the reflection elements 30-1 to 30-n, respectively, input to the same individual wavelength port, and multiplexed again. Is done. The light multiplexed again by the wavelength multiplexing / demultiplexing element 24 passes through the reflection element 22b with almost no loss and enters the optical amplification fiber 20, where it is amplified and transmitted through the reflection element 22a with almost no loss. Then, the light reaches the reflection element 28 and is reflected by the reflection element 28.

As described above, of the 1.5 μm band light in which Er added to the optical amplification fiber 10 is generated, wavelength separation and reflection are performed by the wavelength multiplexing / demultiplexing element 24 and the reflecting elements 30-1 to 30-n. The light components of the wavelengths λ1 to λn
A round trip is performed between the reflection element 28 and the reflection elements 30-1 to 30-n, and finally laser oscillation is caused by stimulated emission in the optical amplification fiber 20. Of course, as in the embodiment shown in FIG. 1, when laser oscillation output is not required,
There is no need for laser oscillation. One optical amplification fiber 2
0, a large number of wavelengths λ1 to λn can be amplified collectively, and temperature control for strictly controlling wavelengths is not required.
The structure is simple and can be manufactured at low cost.

The reflectance of the reflection elements 30-1 to 30-n is set to 1
By setting the ratio to less than 00%, laser oscillation light of each wavelength λ1 to λn is transmitted through the reflective elements 30-1 to 30-n and output to the outside. That is, laser oscillation light of each wavelength λ1 to λn can be obtained individually.

In the embodiment shown in FIG. 2, the excitation light for directly exciting the light-emitting element Er that emits light in the main wavelength band is confined in the optical amplification fiber 20 by the reflection elements 22a and 22b, and the intensity is high. , A very high excitation efficiency can be achieved and a very high intensity output can be obtained.

In the embodiment shown in FIG. 2, Er and Tm were added together to the same fluoride fiber. However, the luminous medium to which Er was added and the luminous medium to which Tm were added were separately manufactured and connected serially. Is also good.

The same structure as that of the embodiment shown in FIG.
A high intensity multi-wavelength light source in a band can be realized. To this end, the optical amplification fiber 20 is a fluoride fiber doped with Pr and Yb, and the excitation light source 26 is a 0.98 μm band semiconductor laser. Of course, the reflection elements 22a and 22b are 1.02 μm.
The reflection element selectively reflects 100% of the m band but transmits the 1.3 μm band, and the reflection element 28 transmits the 0.98 μm band but reflects 100% of the 1.3 μm band. The wavelength multiplexing / demultiplexing element 24 is an element that wavelength-demultiplexes and multiplexes the desired wavelengths λ1 to λn in the 1.3 μm band, and the reflection elements 30-1 to 30-n are the desired wavelength λ in the 1.3 μm band.
1 to λn.

In this case, the excitation light generated by the excitation light source 26 excites the light emitting element Yb in the optical amplification fiber 20 to generate 1.02 μm band light. The 1.02 μm band light is confined in the optical amplification fiber 20 by the reflection elements 22a and 22b, and another light-emitting element Pr in the optical amplification fiber 20.
To generate 1.3 μm band light. The light of wavelengths λ1 to λn included in the 1.3 μm band light round-trips between the reflection element 28 and the reflection elements 30-1 to 30-n, and finally oscillates.

In each of the above embodiments, the wavelength λ1 to λ of the output light
n and its quality are determined by the wavelength demultiplexing (multiplexing) characteristics of the wavelength demultiplexing / demultiplexing elements 12 and 24 and the reflection elements 18-1 to 18-.
n, 30-1 to 30-n. Therefore, each of the reflection elements 18-1 to 18-n, 30
Obviously, instead of -1 to 30-n, a reflective element having no or low wavelength selectivity, or a reflective element having the same characteristic that reflects all of λ1 to λn may be used. If the wavelength demultiplexing performance of the wavelength division multiplexing / demultiplexing elements 12 and 24 is high, each of the reflecting elements 18-1 to 18-n and 30-1 to 30-
The reflection wavelength characteristic of n may be broader with respect to the center wavelengths λ1 to λn, and adjacent reflection elements 18-1 to 18-n,
The reflection wavelength characteristics of 30-1 to 30-n may overlap.

When a sufficient gain can be obtained with the optical amplification fibers 10 and 20, instead of the wavelength division multiplexing / demultiplexing elements 12 and 24, the input light is simply divided into a plurality of parts and a plurality of inputs are divided by one.
Alternatively, a multiplexing / demultiplexing element that multiplexes the signals may be used. In that case, each of the reflection elements 18-1 to 18-n, 30-1 to 30-
The wavelength of the output light can be selected according to the reflection wavelength characteristic of n.
However, this configuration is not suitable for obtaining many output wavelengths because the loss in the multiplexing / demultiplexing element increases as the number of wavelengths increases.

In the embodiment shown in FIG.
0, and in the embodiment shown in FIG. 2, between the reflecting element 22b and the wavelength multiplexing / demultiplexing element 24,
It reflects the wavelength λp of the pumping light output from the pumping light sources 14 and 26, but emits the light emitting element Er added to the optical amplification fibers 10 and 20 in a 1.5 μm band, more specifically, the output wavelengths λ1 to λn. A reflective element that transmits light may be provided.
Then, the pump light propagating through the optical amplification fibers 10 and 20 is reflected by the reflection element, and is again returned to the optical amplification fiber 1.
Since the values are input to 0 and 20, the excitation efficiency is improved.

As the wavelength division multiplexing / demultiplexing elements 12 and 24,
As described above, an arrayed waveguide type diffraction grating or a blazed type diffraction grating can be applied. However, from the viewpoint of simplicity of the device configuration and compatibility with the wavelength division multiplexing optical communication system, the arrayed waveguide type diffraction grating is preferred. Is suitable. For example, if a dumbbell waveguide type diffraction grating having 1 × 8 channels is used, the channel spacing is 1.6 nm, and λ1 is 1549.5 nm, λ1
1551.1 nm as 2 and 1552.7 n as λ3
m, 1554.3 nm as λ4 and 155 as λ5
5.9 nm, 1557.5 nm as λ6, 1559.1 nm as λ7, and 1560.7 nm as λ8, so that an eight-wavelength wavelength multiplexed light source can be realized.

Reflecting elements 16, 18-1 to 18-n, 22
a, 22b, 28, 30-1 to 30-n are made of, for example, an optical fiber grating or a multilayer mirror. Considering the coupling efficiency of input and output light and ease of manufacturing,
An optical fiber grating is more suitable than a multilayer mirror. The optical fiber grating has an advantage that it is easy to adjust its reflection center wavelength to each of the designed output wavelengths λ1 to λn, and it is easy to obtain a narrow band, so that it is easy to manufacture a design specification.

In each of the above embodiments, the output wavelengths λ1 to λn
Are wavelength division multiplexing / demultiplexing elements 12, which are basically passive elements,
24 and reflection elements 18-1 to 18-n, 30-1 to 30
−n, so compared to a semiconductor laser,
The change in output wavelength with temperature is much smaller,
Even without performing high-precision temperature control, a multi-wavelength light source with a stable output wavelength can be obtained, and the reliability can be improved. Further, when the number of wavelengths increases, the wavelength multiplexing / demultiplexing element 1
As the elements 2 and 24, those having a large number of wavelengths are used.
Since it is only necessary to add 2-1 to 18-n and 30-1 to 30-n, even if the number of wavelengths is increased, the apparatus is not so large.

In the above embodiment, the reflecting elements 16 and 28 do not have wavelength characteristics for determining the output wavelengths λ1 to λn, but it is needless to say that the reflecting elements 16 and 28 also have wavelength characteristics. You may give it. In that case, the reflection element 1
The output wavelengths [lambda] 1 to [lambda] n and the quality thereof are determined by the product of the wavelength characteristics of the wavelength multiplexing / demultiplexing elements 12, 24 and the reflecting elements 18-1 to 18-n, 30-1 to 30-n.

[0051]

As can be easily understood from the above description, according to the present invention, a multi-wavelength light source which is inexpensive, highly reliable, highly efficient and outputs multiple wavelengths simultaneously can be realized with a very simple configuration. Since the output wavelength is determined by the passive element, the wavelength stability is good and high-level temperature control is not required. as a result,
Reliability also increases.

Since the second excitation light emitted by the excitation light from the excitation light source is confined by the reflecting member to excite the light emitting element that generates the output wavelength band light, a high excitation light rate can be easily realized, and as a result, , Very high intensity output can be obtained.

[Brief description of the drawings]

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

FIG. 2 is a schematic configuration block diagram of a second embodiment of the present invention.

[Explanation of symbols]

 10: Optical amplifying fiber 12: Wavelength multiplexing / separating element 14: Pump light source 16: Reflecting element 18-1 to 18-n: Reflecting element 20: Optical amplifying fiber 22a, 22b: Reflecting element 24: Wavelength multiplexing / separating element 26: Excitation light source 28: reflective element 30-1 to 30-n: reflective element

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Toshio Tani 2-3-2 Nishi-Shinjuku, Shinjuku-ku, Tokyo International Telephone & Telephone Corporation

Claims (9)

[Claims] 1. An excitation light source for generating excitation light, an optical amplification unit excited by the excitation light to amplify light in a predetermined output wavelength band, and a light source between one end of the optical amplification unit and the excitation light source. connection,
A first reflection member that transmits the excitation light from the excitation light source to the optical amplification unit, but reflects the predetermined output wavelength band, and is connected to the other end of the optical amplification unit; Multiplexing / demultiplexing means for separating the light into a plurality of lights and outputting the light from the individual wavelength port, multiplexing the light input to the individual wavelength port, and outputting the multiplexed light to the optical amplifying means; A second reflection member connected to the wavelength port and reflecting light from the individual wavelength port to return to the individual wavelength port, wherein at least one of the multiplexing / demultiplexing unit and the second reflection member is desired. A multi-wavelength light source having wavelength characteristics corresponding to the output wavelength of the light. 2. The multi-wavelength light source according to claim 1, wherein said light amplifying means comprises a light-emitting medium having a light-emitting means that emits light in said predetermined output wavelength band when excited by said excitation light. 3. The multi-wavelength light source according to claim 2, wherein said light emitting means is made of Er, and said excitation light source is made of any one of a laser light source in a 1.48 μm band and a 0.98 μm band. 4. The light-emitting medium is Pr as the light-emitting means.
3. The multi-wavelength light source according to claim 2, wherein the excitation light source comprises a 1.02 μm-band laser light source. 5. The first light emitting means, wherein the light amplifying means is excited by the excitation light and emits light at a wavelength different from the excitation light, and is excited by the light generated by the first light emitting means. A light-emitting medium including a second light-emitting means for emitting light in the predetermined output wavelength band, and disposed on both sides of the light-emitting medium to reflect light generated by the first light-emitting means,
2. The multi-wavelength light source according to claim 1, comprising a third reflecting member that transmits the light of the predetermined output wavelength band. 6. The light-emitting medium is made of a fluoride fiber doped with Er and Tm, and the third reflection member is made of 1.4.
6. The multi-wavelength light source according to claim 5, comprising a reflecting member that reflects an 8 μm band and transmits a 1.5 μm band, and the excitation light source is a 1.06 μm band laser light source. 7. The light-emitting medium is made of a fluoride fiber doped with Pr and Yb, and the third reflection member is made of
6. The multi-wavelength light source according to claim 5, comprising a reflecting member that reflects the 2 μm band and transmits the 1.3 μm band, and the excitation light source is a 0.98 μm band laser light source. 8. The multiplexing / demultiplexing means separates light from the light emitting means into a plurality of the output wavelengths and outputs the light from an individual wavelength port, and multiplexes the light input to the individual wavelength port to multiplex the light. 2. The multi-wavelength light source according to claim 1, wherein the multi-wavelength light source is a wavelength multiplexing / demultiplexing unit that outputs the light to the light emitting unit. 9. The multi-wavelength light source according to claim 1, wherein said first reflection means and said second reflection means comprise a fiber grating.