JP2013042173A - Optical pulse laser device and optical pulse laser generation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical pulse laser device which can irradiate an object simultaneously with high output ultrashort pulse light beams output from a plurality of laser light sources while adjusting the phase easily and accurately, and can make the whole device compact, and to provide an optical pulse laser generation method.SOLUTION: In the optical pulse laser device, optical gate control means 4, 14 generate pulse signals having a timing for thinning the optical pulses from semiconductor lasers 1, 11 at a regular interval, delay adjustment means 10 adjusts the amount of delay of the pulse signal, and optical gates 3, 13 perform thinning of optical pulses generated from the semiconductor lasers 1, 11 at a regular interval by a drive signal from a signal oscillator 2, and adjust the timing of optical pulses passed through the optical gates 3, 13 and entering optical amplification means 5, 15, and the timing of optical pulses being output from the optical amplification means 5, 15 and impinging on an object.

Description

  The present invention relates to an optical pulse laser device and an optical pulse laser generation method, and more particularly to an optical pulse laser device and an optical pulse laser generation method for generating high-power and ultrashort pulse laser light using a semiconductor laser.

  There is an increasing need in various fields for ultrashort pulse laser light having a pulse width on the order of ps (picoseconds). For example, when observing or measuring a phenomenon that changes in a short time (several hundred ps to several ns), such as a molecular decomposition reaction, or irradiating an observation object with an ultrashort pulse of a different wavelength, In the technical field such as so-called CARS (Coherent Anti-Stokes Raman Scattering) micro-spectroscopic light that observes fluorescence with resolution, there is a particularly high need.

  In addition, in order to generate high-power pulse light that is an ultrashort pulse, a solid-state laser device capable of generating high-power laser light is generally used, which increases the size of the entire device. There is a problem that it is expensive and lacks reliability.

  On the other hand, when irradiating the same object simultaneously with a plurality of pulse lights having different wavelengths or pulse lights having the same wavelength, it is indispensable to accurately adjust the phase timing of the irradiated pulse light. For this reason, when using the solid-state laser device as described above, each solid-state laser is pulse-driven, and each generated pulsed light is derived to the vicinity of the irradiation object using a waveguide means such as an optical fiber, It is possible to irradiate simultaneously.

  However, if the length of the optical fiber that guides the pulsed light is different, the timing at which each pulsed light is applied to the object is shifted, and when guiding pulsed light of a different wavelength through the optical fiber, the chromatic dispersion characteristics As a result, there arises a problem that the phase is shifted between the pulse lights. For this reason, in order to accurately adjust these timings, it is necessary to incorporate an optical delay device in a part of the optical fiber. In particular, in order to adjust the phase shift as described above, a large delay device is required. I must.

  Patent Document 1 discloses a technique for generating high-power and ultrashort pulse laser light using a semiconductor laser instead of using a solid-state laser device.

  In Patent Document 1, a semiconductor laser, an electric pulse generator that generates pulsed light in the semiconductor laser, and a signal from the electric pulse generator, the pulsed light from the semiconductor laser is converted into the pulsed light. An optical pulse laser device including a low-noise optical amplifier that amplifies in synchronization with a laser is shown. In particular, the low noise optical amplifier includes a pulse generator that receives a signal from the electric pulse generator and generates a synchronized pulse, an optical amplifier that amplifies the pulsed light from the semiconductor laser, and the pulse generator. And a gate that allows the amplified pulsed light from the optical amplifier to pass therethrough.

  In the method of Patent Document 1, it is possible to reduce the size of the optical pulse laser device itself. However, however, a plurality of optical pulse laser devices as in Patent Document 1 are provided, and each pulsed light is irradiated onto the object simultaneously. Therefore, as described above, it is necessary to provide a plurality of waveguide means such as optical fibers corresponding to each optical pulse laser device, and it is indispensable to adjust the phase of the pulsed light propagating through each optical fiber or the like. . For this reason, it is still necessary to use a large delay device.

JP 2005-128229 A

  The problem to be solved by the present invention is to solve the above-mentioned problems, and it is possible to reduce the size of the entire apparatus and to easily produce ultra-short pulse high-power pulse light output from a plurality of laser light sources. It is another object of the present invention to provide an optical pulse laser apparatus and an optical pulse laser generation method capable of accurately adjusting a phase and simultaneously irradiating an object.

  In order to solve the above-mentioned problem, the invention according to claim 1 includes a plurality of mode-locked semiconductor lasers that generate pulsed light, a single signal oscillator that inputs a drive signal to each of the semiconductor lasers, An optical gate provided corresponding to the semiconductor laser, which thins out the pulsed light from each semiconductor laser at regular intervals, an optical gate control means for controlling the operation of the optical gate based on a drive signal from the signal oscillator, An optical amplifying means provided corresponding to the optical gate for amplifying and outputting the pulsed light that has passed through each optical gate, and the drive signal is input from the signal oscillator to the specific semiconductor laser and the specific optical gate control means A delay adjusting means is provided in the middle of the signal line, and the optical gate control means generates a pulse signal at a timing for thinning out the optical pulses from the semiconductor laser at regular intervals. The means adjusts the delay amount of the pulse signal, the optical gate thins out the optical pulse generated from the semiconductor laser at a constant interval by the drive signal from the signal oscillator, and the optical pulse that has passed through the optical gate The optical pulse laser device is characterized in that the timing at which the pulsed light input to the means and output from the optical amplifying means is emitted to the object is adjusted.

  The invention according to claim 2 is the optical pulse laser device according to claim 1, wherein the wavelength of the pulsed light generated by each semiconductor laser is different.

  The invention according to claim 3 is the optical pulse laser device according to claim 1 or 2, wherein the pulse width of the pulsed light generated by each semiconductor laser is 1 ns or less.

  The invention according to claim 4 is the optical pulse laser device according to any one of claims 1 to 3, wherein the optical amplifying means is an optical fiber amplifier.

  According to a fifth aspect of the present invention, there are provided a plurality of mode-locked semiconductor lasers for generating pulsed light, a single signal oscillator for inputting a driving signal to each of the semiconductor lasers, and a corresponding one of the semiconductor lasers. An optical gate that thins out the pulsed light from each semiconductor laser at regular intervals, an optical gate control means for controlling the operation of the optical gate based on a drive signal from the signal oscillator, and a corresponding optical gate. The optical amplifying means for amplifying and outputting the pulsed light that has passed through each optical gate, and a delay in the middle of the signal line for inputting the drive signal from the signal oscillator to the specific semiconductor laser and the specific optical gate control means A step of generating a pulse signal at a timing for thinning out light pulses from the semiconductor laser at a constant interval by the optical gate control unit; A step of adjusting a delay amount of the pulse signal, a step of thinning out light pulses generated from the semiconductor laser based on a drive signal from the signal oscillator by the optical gate at a predetermined interval, and an optical pulse passing through the optical gate. Is input to the optical amplifying means, and the timing at which the pulsed light output from the optical amplifying means is emitted to the object is adjusted.

  According to the first aspect of the present invention, a plurality of mode-locked semiconductor lasers for generating pulsed light, a single signal oscillator for inputting a drive signal to each semiconductor laser, and a corresponding one for each semiconductor laser are provided. An optical gate that thins out the pulsed light from each semiconductor laser at regular intervals, an optical gate control means for controlling the operation of the optical gate based on a drive signal from the signal oscillator, and a corresponding optical gate. Because it is an optical pulse laser device that uses optical amplification means that amplifies and outputs pulsed light that has passed through each optical gate, the optical pulse laser device that generates ultra-short pulse and high-output pulsed light is compact. Can be realized.

  Furthermore, since the semiconductor laser is a mode-locked laser, it becomes possible to stably output pulsed light having a specific wavelength. In addition, by using a mode-locked laser, it is possible to output pulsed light of different wavelengths even with drive signals from the same oscillator when the materials composing the semiconductor are different. In order to drive this semiconductor laser, it becomes possible to control it very easily and accurately.

  Further, a delay adjusting means is provided in the middle of a signal line for inputting a drive signal from the signal oscillator to the specific semiconductor laser and the specific optical gate control means, and the optical gate control means distributes the light pulses from the semiconductor laser at regular intervals. The delay adjusting means adjusts the delay amount of the pulse signal, and the optical gate thins out the optical pulse generated from the semiconductor laser at a constant interval by the drive signal from the signal oscillator. In order to adjust the timing at which the optical pulse that has passed through the optical gate is input to the optical amplifying means and the pulsed light output from the optical amplifying means is emitted to the object, a simple circuit configuration relating to an electrical signal is used. Therefore, the generation timing of the pulsed light can be adjusted more accurately, and as a result, the timing at which the target object is irradiated with the pulsed light can also be adjusted accurately. That.

  According to the second aspect of the present invention, the wavelength of the pulsed light generated by each semiconductor laser is different. Therefore, even if a phase shift occurs between the pulsed light due to the wavelength dispersion characteristics, the present invention makes it easy to adjust the phase. Yes, it becomes possible to simultaneously irradiate the object with pulsed light of different wavelengths.

  According to the invention of claim 3, since the pulse width of the pulsed light generated by each semiconductor laser is 1 ns or less, the optical pulse laser device of the present invention is more preferably applied to the generation of ultrashort pulses. Is possible.

  According to the invention of claim 4, since the optical amplifying means is an optical fiber amplifier, it becomes possible to efficiently amplify ultrashort pulse light.

  According to the invention of claim 5, a plurality of mode-locked semiconductor lasers for generating pulsed light, a single signal oscillator for inputting a drive signal to each semiconductor laser, and a corresponding one for each semiconductor laser are provided. An optical gate that thins out the pulsed light from each semiconductor laser at regular intervals, an optical gate control means for controlling the operation of the optical gate based on a drive signal from the signal oscillator, and a corresponding optical gate. The optical pulse laser generation method using the optical amplification means that amplifies and outputs the pulsed light that has passed through each optical gate, and therefore, an optical pulse laser device that generates ultrashort pulse and high output pulsed light. It becomes possible to reduce the size.

  Furthermore, since the semiconductor laser is a mode-locked laser, it becomes possible to stably output pulsed light having a specific wavelength. In addition, by using a mode-locked laser, it is possible to output pulsed light of different wavelengths even with drive signals from the same oscillator when the materials composing the semiconductor are different. In order to drive this semiconductor laser, it becomes possible to control it very easily and accurately.

  Further, a delay adjusting means is provided in the middle of the signal line for inputting the drive signal from the signal oscillator to the specific semiconductor laser and the specific optical gate control means, and the optical pulse from the semiconductor laser is fixed by the optical gate control means. A step of generating a pulse signal at a timing to be thinned out at intervals, a step of adjusting a delay amount of the pulse signal by the delay adjusting means, and a light generated from the semiconductor laser based on a drive signal from the signal oscillator by the optical gate A step of thinning out the pulses at regular intervals; and a step of inputting the optical pulse that has passed through the optical gate to the optical amplifying unit; and a timing at which the pulsed light output from the optical amplifying unit is emitted to the object. As a result of adjustment, the pulse light generation timing can be adjusted more accurately with a simple circuit configuration related to electrical signals. To the timing of the pulsed light on the object is irradiated may also be adjusted accurately.

It is the schematic of the optical pulse laser apparatus of this invention.

The optical pulse laser apparatus and optical pulse laser generation method of the present invention will be described below.
FIG. 1 shows a schematic diagram of an optical pulse laser device.
The optical pulse laser device is provided corresponding to each semiconductor laser, a plurality of semiconductor lasers 1 and 11 that generate pulsed light, a single signal oscillator 2 that inputs a drive signal to each semiconductor laser, and each semiconductor laser. Optical gates 3 and 13 for thinning out pulsed light from a semiconductor laser at regular intervals, optical gate control means 4 and 14 for controlling the operation of the optical gate based on a drive signal from the signal oscillator 2, and each optical gate 3 , 13 for amplifying and outputting the pulsed light that has passed through each optical gate, and from the signal oscillator 2 to the specific semiconductor laser 11 and the specific optical gate control means 14. The delay adjusting means 10 is provided in the middle of the signal line for inputting the drive signal. Then, the high-power ultrashort pulse light output from each of the optical amplifying means 5 and 15 propagates through the waveguide means 6 and 16 such as an optical fiber, and is irradiated to the object 20 or the like disposed outside.

  The semiconductor lasers 1 and 11 use mode-locked lasers. Mode-locked lasers can stably generate pulsed light with a specific wavelength. Especially when outputting pulsed light with different wavelengths, mode-locked lasers with different base semiconductor materials are used. By using, it becomes possible to generate pulsed light having different wavelengths despite the application of pulses having the same frequency.

The optical gates 3 and 13 include a semiconductor optical amplifier (Semiconductor Optical Amplifier).
(Amplifier) can be preferably used, but any optical gate capable of high-speed passage control for pulsed light having a pulse width of the order of ps can be applied to the present invention without being limited to SOA.

  The optical gates 3 and 13 are driven by optical gate control means 4 and 14, respectively. The optical gate is driven and controlled at a timing required to thin out light pulses from the semiconductor laser at regular intervals. For example, the same signal as the drive signal applied to the semiconductor lasers 1 and 11 is input to the optical gate control means 4 and 14, the pulse signal constituting the drive signal is divided, and the pulse signal at the timing of thinning out the pulsed light Convert to. In order to roughly adjust the timing of driving the optical gates 3 and 13 and the passage timing of the pulsed light passing through the optical gate, the timing of the thinned pulses can be adjusted.

  The pulsed light that has passed through the optical gates 3 and 13 is input to the optical amplifying means 5 and 15 and converted into high-powered pulsed light. An optical fiber amplifier is used for the optical amplification means 5 and 15. Optical fiber amplifiers have a sufficiently long lifetime at the upper level of laser transitions. By slowing the repetition of incident light pulses, the energy stored in the amplifier can be efficiently transferred to the light pulses. Even with a light pulse from a semiconductor laser, a high peak power exceeding kilowatts can be obtained.

  In the optical pulse generating means composed of a semiconductor laser, an optical gate, an optical amplifier, etc. used in the optical pulse laser apparatus of the present invention, a high output pulse with respect to an ultrashort pulse whose pulse width is 1 ns or less It has been confirmed that light can be generated, and can be said to be an extremely useful light pulse generating means.

  Further, in order to remove as much as possible noise of the pulsed light entering the optical amplifying means 5 and 15, for example, a wavelength filter is provided between the optical gate 3 and the optical amplifying means 5 or in the middle of the waveguide means 6 to reduce the noise. It is also possible to remove the wavelength light that becomes.

  The features of the optical pulse laser apparatus and optical pulse laser generation method of the present invention are as follows: when a drive signal from a single signal oscillator 2 is applied to a specific semiconductor laser 11 or a specific optical gate control means 14 In order to adjust the timing of irradiating a plurality of pulse lights to 20, a delay adjusting means 10 such as a delay circuit is provided in the middle of a signal line for transmitting a drive signal, and the gate timing of the optical gate means 4, 14 is adjusted. It is characterized by doing. Of course, it is preferable that the delay amount of the delay adjusting means be adjustable.

  In the embodiment of FIG. 1, two examples of the semiconductor laser driven from the single signal oscillator 2 are shown. However, the present invention is not limited to this, and two or more semiconductor lasers can be used. Accordingly, a plurality of signal oscillators can share and drive several semiconductor lasers. In this case, the synchronization control means is used to synchronize the pulses between the signal oscillators. Intervene between signal oscillators.

  Further, in FIG. 1, the drive signal emitted from the signal oscillator 2 is branched and used for the semiconductor laser 1 (11) and the optical gate control means 4 (14) in the same optical pulse generation means. It is also possible to provide the signal oscillator 2 with a plurality of terminals for outputting drive signals having the same frequency, and to connect the terminals individually to the semiconductor laser 1 (11) and the optical gate control means 4 (14).

  Further, the delay adjusting means 10 can be provided with a delay control circuit individually on the signal line after branching from the signal oscillator 2 to the semiconductor laser 11 and the optical gate control means 14 instead of the one shown in FIG. is there.

  According to the present invention, it is possible to reduce the size of the entire apparatus, and to easily and accurately adjust the phase of an ultrashort pulsed and high-power pulsed light output from a plurality of laser light sources to be an object. An optical pulse laser device and an optical pulse laser generation method capable of simultaneous irradiation can be provided.

DESCRIPTION OF SYMBOLS 1,11 Semiconductor laser 2 Signal oscillator 3,13 Optical gate 4,14 Optical gate control means 5,15 Optical amplification means 6,16 Waveguide means 10 Delay control means 20 Object

Claims (5)

A plurality of mode-locked semiconductor lasers that generate pulsed light; and
A single signal oscillator for inputting a drive signal to each semiconductor laser;
An optical gate provided corresponding to each semiconductor laser, which thins out pulsed light from each semiconductor laser at regular intervals;
Optical gate control means for controlling the operation of the optical gate based on a drive signal from the signal oscillator;
An optical amplifying means provided corresponding to each optical gate and amplifying and outputting the pulsed light that has passed through each optical gate;
In the middle of a signal line for inputting the drive signal from the signal oscillator to a specific semiconductor laser and a specific optical gate control unit, a delay adjusting unit is provided,
The optical gate control means generates a pulse signal at a timing for thinning out the optical pulses from the semiconductor laser at regular intervals,
The delay adjusting means adjusts the delay amount of the pulse signal,
The optical gate thins out light pulses generated from the semiconductor laser at regular intervals by a drive signal from the signal oscillator,
An optical pulse that has passed through the optical gate is input to the optical amplification means,
An optical pulse laser device characterized by adjusting a timing at which pulsed light output from the optical amplification means is emitted to an object.   2. The optical pulse laser device according to claim 1, wherein the wavelength of the pulsed light generated by each semiconductor laser is different.   3. The optical pulse laser device according to claim 1, wherein the pulse width of the pulsed light generated by each semiconductor laser is 1 ns or less.   4. The optical pulse laser apparatus according to claim 1, wherein the optical amplification means is an optical fiber amplifier. A plurality of mode-locked semiconductor lasers that generate pulsed light; and
A single signal oscillator for inputting a drive signal to each semiconductor laser;
An optical gate provided corresponding to each semiconductor laser, which thins out pulsed light from each semiconductor laser at regular intervals;
Optical gate control means for controlling the operation of the optical gate based on a drive signal from the signal oscillator;
An optical amplifying means provided corresponding to each optical gate and amplifying and outputting the pulsed light that has passed through each optical gate;
In the middle of a signal line for inputting the drive signal from the signal oscillator to a specific semiconductor laser and a specific optical gate control unit, a delay adjusting unit is provided,
Generating a pulse signal at a timing for thinning out light pulses from the semiconductor laser at regular intervals by the optical gate control means;
Adjusting the delay amount of the pulse signal by the delay adjusting means;
Thinning out light pulses generated from the semiconductor laser at regular intervals based on a drive signal from the signal oscillator by the optical gate;
The optical pulse that has passed through the optical gate is input to the optical amplification means,
A method of generating an optical pulse laser, comprising adjusting a timing at which pulsed light output from the optical amplifying means is emitted to an object.

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