JP2002287189A - Multi-wavelength short pulsed light generating device at short wavelength - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multi-wavelength short pulsed light generating device at short wavelengths in which a plurality of second harmonic waves with different wavelengths can be obtained in one optical fiber and pulsed light with temporally different wavelengths can be obtained from a single optical fiber. SOLUTION: The device is equipped with a short pulse light source (1), a controller (2) for the characteristics of light to control the characteristics of the light from the short pulse light source (1), an optical fiber (4) where the input pulses from the controller (2) enter, an optical branching device (5) to branch the output light from the optical fiber (4), and a nonlinear optical element (6) which couples the output light from the light branching device (5) and converts the wavelength of the output light. The device outputs short pulsed light (7A) with a plurality of different wavelengths.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a short wavelength multi-wavelength short pulse light generator.

[0002]

2. Description of the Related Art Conventionally, the present inventors have already disclosed in
No. 0-105394, a wavelength-variable short-pulse light generation device capable of changing the wavelength by simply changing the light intensity was developed.

In this wavelength-tunable short-pulse light generating apparatus, pulse light whose wavelength continuously shifts from the pumping light wavelength can be generated using an optical fiber.

[0004]

However, in the above-mentioned conventional wavelength-variable short-pulse light generator, a plurality of second harmonics having different wavelengths cannot be obtained with one optical fiber.

[0005] Pulsed light having different wavelengths in time cannot be obtained from a single optical fiber.

According to the present invention, a plurality of second harmonics having different wavelengths can be obtained with one optical fiber, and pulsed light having different wavelengths in time can be converted into a single light by a single optical fiber. It is an object of the present invention to provide a short-wavelength multi-wavelength short-pulse light generation device obtainable from a fiber.

[0007]

In order to achieve the above object, the present invention provides: [1] a short-wavelength multi-wavelength short-pulse light generating apparatus which includes a short-pulse light source and the characteristics of light from the short-pulse light source. An optical characteristic adjuster to be adjusted, an optical fiber into which an incident pulse from the optical characteristic adjuster is incident, an optical splitter for splitting output light from the optical fiber, and an output light from the optical splitter are coupled. And a non-linear optical element for converting the wavelength of the output light to output short pulse light of a plurality of different wavelengths.

[2] The apparatus for generating short-wavelength / multi-wavelength short-pulse light according to [1], wherein the optical characteristic adjuster is a light intensity modulator for electrically adjusting light intensity. I do.

[3] In the short-wavelength / multi-wavelength short-pulse light generating apparatus according to the above [2], the light intensity modulator is connected to an oscillator for generating a temporally periodic signal, It is characterized in that short pulse lights of different wavelengths are generated.

[4] The short-wavelength / multi-wavelength short-pulse light generating apparatus according to [1], wherein the nonlinear optical elements are adjusted to generate second harmonics at different wavelengths.

[5] In a short wavelength multi-wavelength short pulse light generating apparatus, a short pulse light source, an optical characteristic adjuster for adjusting characteristics of light from the short pulse light source, and an incident pulse from the optical characteristic adjuster are used. An incident optical fiber, an optical splitter for splitting output light from the optical fiber, a non-linear optical element for coupling the output light from the optical splitter and converting the wavelength of the output light, An optical coupler for coupling the output light of the element, wherein a plurality of short pulse lights of different wavelengths are output from a single optical path.

[0012]

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

FIG. 1 is a block diagram of a short wavelength multi-wavelength short pulse light generating apparatus according to a first embodiment of the present invention.

In this figure, 1 is an ultrashort pulse laser as a short pulse light source, 2 is its ultrashort pulse laser 1
A light intensity modulator as an optical characteristic adjuster for receiving the output light from the controller, 3 is a controller connected to the light intensity modulator 2, 4 is a negative dispersion optical fiber connected to the light intensity modulator 2, and 5 is a negative dispersion optical fiber. An optical splitter connected to the dispersion optical fiber 4, 6
Is a nonlinear crystal (nonlinear optical element) connected to the optical splitter 5, 7A is output light of the nonlinear crystal 6, and a second harmonic 8A is superimposed. The output light 7A may pass through a wavelength filter (not shown) to extract the second harmonic 8A as output light.

In FIG. 1, an output light 1 A from an ultrashort pulse laser 1 is electrically changed in intensity by a light intensity modulator 2. The output of the light intensity modulator 2 is input to the negative dispersion variable optical fiber 4, and a wavelength-tunable ultrashort pulse light (output of the negative dispersion optical fiber) 4 </ b> A is generated by the nonlinear optical effect of the negative dispersion optical fiber 4. The ultra-short-wavelength pulsed light 4A, which is the output light of the negative dispersion optical fiber 4, is
The light is split into a plurality of pulse lights, and is incident on the nonlinear crystal 6. Each nonlinear crystal 6 is adjusted so that the second harmonic is efficiently generated at different wavelengths. Therefore, when the wavelength of the wavelength-variable ultrashort pulsed light 4A of the negative dispersion optical fiber 4 is adjusted to change with time, the second harmonic, which is the output light 7A, is obtained only when the wavelength of each nonlinear crystal 6 matches the characteristics of the crystal. Wave pulse light is generated.

FIG. 2 shows a measurement result of an optical spectrum at the output of the optical fiber after light intensity modulation according to the first embodiment of the present invention.

Here, the wavelength of the wavelength-variable ultrashort pulsed light 4A output from the negative dispersion optical fiber 4 changes periodically with time. Further, the generated output light 7A has a sech2 type spectral waveform.

When the optical fiber length is 220 m, 1.5
A soliton pulse is generated over a wide band of 6 to 1.75 μm or more. So far, a wavelength shift of up to 2.03 μm has been observed.

FIG. 3 shows an autocorrelation waveform of a soliton pulse time waveform observed at the output of the optical fiber according to the first embodiment of the present invention.

Here, the autocorrelation waveform is the ideal sec
It corresponds to the h2 type. Optical fiber length is 2
At 20 m, a pulse light of about 300 fs is obtained.

FIG. 4 is a block diagram of a short-wavelength / multi-wavelength short-pulse light generating apparatus according to a second embodiment of the present invention.

In this figure, 11 is an ultrashort pulse laser as a short pulse light source, 12 is a light intensity modulator as an optical characteristic adjuster for receiving output light 11A from the ultrashort pulse laser 11, and 13 is its light intensity A controller connected to the modulator 12, a negative dispersion optical fiber 14 connected to the light intensity modulator 12, a wavelength-variable ultrashort pulse light (negative dispersion optical fiber output) 14A, an optical splitter 15 and a nonlinear 16 A crystal, 17 is an optical coupler, 18 is an optical fiber, 19 is a wavelength filter, and 20 is a single optical output fiber.

In this embodiment, in addition to the configuration of the short wavelength multi-wavelength short pulse light generating device of the first embodiment, each nonlinear crystal 16
The output light 16A is coupled by the optical coupler 17 so that all the output light 17A can be obtained from one optical fiber 18.
A wavelength filter 19 is provided on the output side of the optical fiber 18. At this time, by adjusting the light intensity modulator 12, pulse output light (second harmonic) 19A having a temporally different wavelength can be obtained from the output of the single optical output fiber 20.

FIG. 5 shows the result of observation of the optical spectrum of output light in the second embodiment of the present invention.

As is apparent from this figure, the nonlinear crystal has the second crystal at wavelengths of 812 nm, 833 nm and 863 nm.
It is designed to generate harmonics efficiently. Also, at the output of the optical fiber 18, ultrashort pulsed light 17A having three different wavelengths is generated.

It should be noted that the present invention is not limited to the above embodiment, and various modifications are possible based on the spirit of the present invention, and these are not excluded from the scope of the present invention.

[0027]

As described above, according to the present invention, the following effects can be obtained.

(A) After changing the intensity of transmitted light in a light intensity modulator, the pulsed light output from the excitation light source is put into a negative dispersion optical fiber, and then split into a plurality of pulsed lights by an optical splitter. Incident on the nonlinear crystal. Since the output of each nonlinear crystal is adjusted so that the second harmonic is efficiently generated at different wavelengths, the second harmonic pulse light should be generated only when the wavelength matches the characteristics of the crystal. Can be.

(B) After the configuration of (A), all outputs can be taken out from one optical fiber by inserting an optical coupler.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a short-wavelength, multi-wavelength short-pulse light generating apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a measurement result of an optical spectrum at an output of the optical fiber after optical intensity modulation of the optical fiber according to the first embodiment of the present invention.

FIG. 3 is a diagram showing an autocorrelation waveform of a time waveform of a soliton pulse observed at the output of the optical fiber according to the first embodiment of the present invention.

FIG. 4 is a configuration diagram of a short-wavelength / multi-wavelength short-pulse light generating apparatus according to a second embodiment of the present invention.

FIG. 5 is a diagram illustrating an observation result of an optical spectrum of output light in a second example of the present invention.

[Explanation of symbols]

1,11 Ultrashort pulse laser (short pulse light source) 1A, 11A Output light from ultrashort pulse laser 2,12 Light intensity modulator (optical characteristic adjuster) 3,13 Controller 4,14 Negative dispersion optical fiber 4A, 14A Negative dispersion optical fiber output (tunable ultrashort pulse light) 5,15 Optical splitter 6,16 Nonlinear crystal (nonlinear optical element) 7A, 16A Nonlinear crystal output light 8A, 19A Second harmonic (pulse output light) 17 Optical coupler 17A Output light from one optical fiber 18 Optical fiber 19 Wavelength filter 19A Pulse output light (second harmonic) 20 Single optical output fiber

Continued on the front page F term (reference) 2K002 AB12 AB32 BA02 DA10 GA10 HA13 HA20 HA25

Claims (5)

[Claims] (A) a short pulse light source; (b) an optical characteristic adjuster for adjusting characteristics of light from the short pulse light source;
Coupling an optical fiber into which an incident pulse from the optical property adjuster is incident, (d) an optical splitter for splitting output light from the optical fiber, and (e) output light from the optical splitter; A nonlinear optical element for converting the wavelength of the output light, and (f)
A short-wavelength, multi-wavelength short-pulse light generation device that outputs a plurality of short-pulse lights having different wavelengths. 2. The short-wavelength multi-wavelength short-pulse light generating apparatus according to claim 1, wherein said optical characteristic adjuster is a light intensity modulator adapted to electrically adjust light intensity. Multi-wavelength short pulse light generator. 3. The short-wavelength multi-wavelength short-pulse light generating apparatus according to claim 2, wherein the light intensity modulator is connected to an oscillator that generates a temporally periodic signal, and the wavelengths are different from each other periodically. A short-wavelength multi-wavelength short-pulse light generating device characterized in that the short-pulse light is generated. 4. The short-wavelength multi-wavelength short-pulse light generating apparatus according to claim 1, wherein the nonlinear optical elements are adjusted so as to generate second harmonics at different wavelengths. Pulse light generator. 5. A short-pulse light source, (b) an optical characteristic adjuster for adjusting characteristics of light from the short-pulse light source, and (c)
Coupling an optical fiber into which an incident pulse from the optical property adjuster is incident, (d) an optical splitter for splitting output light from the optical fiber, and (e) output light from the optical splitter; A nonlinear optical element for converting the wavelength of the output light, and (f) an optical coupler for coupling the output light of the nonlinear optical element,
(G) A short-wavelength, multi-wavelength short-pulse light generation device that outputs a plurality of short-pulse lights having different wavelengths from a single optical path.