JPH06275922A - Multiwavelength light source - Google Patents

Abstract

PURPOSE:To obtain a multiwavelength light source generating a multifrequency light of which a frequency interval is fixed, without preparing a large number of laser light sources and without using a control means of high degree. CONSTITUTION:This multiwavelength light source is equipped with a single- frequency laser light source 3, an optical fiber 4 generatin Brillouin light, a first light input means (first photocoupler) 1 inputting an output light from the laser light source 3 to the optical fiber 4, a reversely propagated light takeout means (the first photocoupler) 1 taking out a reversely propagated light from the optical fiber, a light amplifying means 5 for amplifying the reversely propagated light, and a second light input means (second photocoupler) 2 inputting the amplified light to the optical fiber 4 from the same direction as the output light from the laser light source 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-wavelength light source which emits light of different frequencies with uniform frequency intervals.

[0002]

2. Description of the Related Art As a means for generating light of different frequencies, a construction is generally used in which a large number of single-frequency lasers oscillating at different frequencies are prepared and the oscillation light from each laser is combined. . However, in this configuration, a large number of laser light sources must be prepared, and moreover, if an attempt is made to make the intervals of each frequency constant, a sophisticated control means is required.

[0003]

However, the above-mentioned prior art has a problem that it requires a plurality of laser light sources that oscillate at different frequencies and a sophisticated control means that keeps the intervals of the combined multiple frequencies constant. there were.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a frequency interval without preparing a large number of laser light sources and without using sophisticated control means. It is to provide a multi-wavelength light source that generates constant multi-frequency light.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[0006]

In order to achieve the above object, a multi-wavelength light source according to the present invention comprises a single frequency laser light source and an output light from the single frequency laser light source input to an optical fiber. 1 optical input means, counter-propagating light extracting means for extracting counter-propagating light from the optical fiber, amplifying means for amplifying the counter-propagating light, and the single-frequency laser light source for the amplified light in the optical fiber The main feature is that it has a second light input means for inputting the output light from the same direction.

[0007]

According to the above-mentioned means, since the phenomenon called stimulated Brilliant scattering is utilized, one laser light source
A multi-wavelength light source with a constant frequency interval can be realized.

[0008]

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

First, the principle of the present invention will be described. The present invention utilizes the stimulated Brilliant scattering phenomenon of an optical fiber. When a certain level of light is input to the optical fiber, a phenomenon called stimulated Brilliant scattering is induced.

This is because "the interaction between the input light and the acoustic phonons in the fiber medium causes light of a new frequency shifted from the input light frequency to be generated in the opposite direction to the input light."
Is a phenomenon. The amount of frequency shift is peculiar to the fiber medium, and is about 10 GHz for light with a wavelength of 1.5 μm.
Is. The input level at which stimulated brilliant light begins to occur is called the brilliant threshold. The brilliant threshold is
Depending on the fiber length, the spectral line width of the input light, etc., for example, an experimental example has been reported in which the fiber length is 13.6 km and the input light beam width is 1.6 MHz and the Brillian threshold is 10 mW. The present invention has realized a multi-wavelength light source using the Brillian scattering.

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

In the multi-wavelength light source of this embodiment, as shown in FIG. 1, the output light from the laser light source 3 is input to the optical fiber 4 through the first optical coupler 1. Here, it is assumed that the laser light source 3 oscillates at a single frequency, and its output power is larger than the above-mentioned Brilliant threshold value at the time of input to the optical fiber 4. In order to satisfy this output condition, the optical amplifier 5 may be inserted after the laser light source 3 as required.

In the optical fiber 4, light whose frequency is shifted by Δf from the input light frequency is generated in the opposite direction to the input light due to the Brilliant scattering phenomenon. A part of this Brilliant light is extracted by the first optical coupler 1. The extracted Brillian light is input to the second optical coupler 2.
A loop 6 is formed on the output side of the second optical coupler 2, and the light input from the first optical coupler 1 is the loop 6
It is configured to return to the first optical coupler 1 again through the. The light returned to the first optical coupler 1 is input to the optical fiber 4 from the same direction as the original laser light.

An optical amplifier 5 is inserted in the loop 6. A directional amplifier is used as the optical amplifier 5. This optical amplifier 5 allows only one direction in the loop 6,
For example, only counterclockwise light is propagated. Further, the output level of the optical amplifier 5 is set so that the input level when the light output from the loop 6 is input to the optical fiber 4 via the first optical coupler 1 is equal to or higher than the Brilliant threshold. Keep it.

With the above structure, the Brilliant light from the optical fiber 4 is input to the optical fiber 4 again after its optical power is amplified. Due to the input first brilliant light, the frequency is shifted by Δf from the second light.
Brilliant light is emitted.

Further, the second Brilliant light is again input to the optical fiber 4, whereby the frequency is further increased by Δf.
The third shifted Brilliant light is generated. When this process is sequentially repeated, the output end 7 of the optical fiber 4 outputs multi-wavelength light with a frequency interval Δf.

It is conceivable that amplified noise light is generated in the optical amplifier 5, which adversely affects the multi-wavelength light generation operation. In order to prevent this, an optical filter for removing amplified noise light may be inserted immediately after the optical amplifier 5, if necessary. However, in this case, the wavelength range of the generated multi-wavelength light is limited within the optical filter band.

Further, in the Brillian scattering process, it is considered that the spectral line width of the brilliant light generated becomes wider than the line width of the original light. Therefore, the higher the brilliant light generated, the wider the line width may be. In order to prevent this, an optical filter for narrowing the line width may be inserted in any place other than between the laser light source 1 and the first optical coupler 1 if necessary. This is possible, for example, by using a Fabry-Perot filter or a ring resonator filter whose transmission spectrum interval (FSR) is Δf.

Although the present invention has been specifically described based on the embodiments, it goes without saying that various modifications can be made without departing from the scope of the invention.

[0020]

As described above, according to the present invention, since a phenomenon called stimulated Brillian scattering is utilized, it is possible to realize a multi-wavelength light source having a constant frequency interval with one laser light source.

[Brief description of drawings]

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

[Explanation of symbols]

1 ... 1st optical coupler, 2 ... 2nd optical coupler, 3 ... laser light source, 4 ... optical fiber, 5 ... optical amplifier, 6 ... loop, 7
… Output end.

Claims (1)

[Claims] 1. A single-frequency laser light source, a first optical input means for inputting output light from the single-frequency laser light source into an optical fiber, and a counter-propagating light extracting means for extracting counter-propagating light from the optical fiber. And an amplification means for amplifying the counter-propagating light,
A multi-wavelength light source, comprising: a second light input means for inputting the amplified light into the optical fiber in the same direction as the output light from the single-frequency laser light source.