JP2018032824A - Optical pulse signal generating device, laser processing device and bio imaging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve an optical pulse with a time width equal to or more than sub-nanosecond.SOLUTION: An optical pulse signal generating device 1 includes: a laser source 11; a semiconductor laser optical amplifier 12 which receives laser beam from the laser source 11 as an input signal and receives, as a control signal, an electric pulse signal with a time width equal to or more than sub-nanosecond at the timing that laser beam is input to generate an optical pulse signal with a time width equal to or more than sub-nanosecond.SELECTED DRAWING: Figure 1

Description

  The technology described in this specification relates to an optical pulse signal generation device, a laser processing device, and a bio-imaging device.

  In recent years, applications of bioimaging and laser processing have demanded flexible optical pulse control not only in the femtosecond and picosecond time regions, but also in the sub-nanosecond and higher time regions. It is assumed that such an optical pulse is used after being amplified and having a high peak power. Therefore, in order to prevent the optical pulse from being buried in the noise in the amplification process, it is desirable that the optical pulse having the largest possible pulse energy is generated first.

  Conventionally, the following techniques are disclosed for pulse generation. For example, there is a method of generating an ultrashort pulse on the order of picoseconds by removing a laser pulse generated by a gain switching operation with a filter (see, for example, Patent Document 1 below). In addition, there is a method of generating an ultrashort pulse and a high output optical pulse by thinning out pulsed light from a semiconductor laser at a constant interval by an optical gate (see, for example, Patent Document 2 below).

JP2013-157551A JP 2008-242306 A

  However, for example, it may be possible to use the gain switching operation of the semiconductor laser described above. However, in principle, it is not easy to obtain an optical pulse having a time width of sub-nanoseconds or more with a semiconductor laser using such a gain switching operation. Further, for example, it is conceivable to obtain a light pulse having a time width of at least sub-nanoseconds using the Q switching method. However, even with such a method, it is not easy to control the time width of at least sub-nanoseconds.

  In order to solve the problems of the conventional technology, in one aspect, the technology described in this specification aims to obtain a light pulse having a time width of sub-nanoseconds or more.

  In one aspect, the optical pulse signal generation device receives a laser light source and laser light from the laser light source as an input signal, and has a time width of at least sub-nanoseconds at the timing when the laser light is input. A semiconductor laser optical amplifier that generates an optical pulse signal having a time width of at least sub-nanosecond by receiving an electric pulse signal as a control signal is configured.

  By adopting such a configuration, the problems of the prior art are solved, and in the present invention, as one aspect, an optical pulse having a time width of sub-nanoseconds or more can be obtained.

It is a block diagram which shows the structural example of the optical pulse signal generation apparatus of 1st Embodiment. 2 is a graph illustrating an outline of a signal waveform obtained by the optical pulse signal generation device illustrated in FIG. 1. It is a block diagram which shows the structural example of the optical pulse signal generation apparatus of the modification of 1st Embodiment. It is a block diagram which shows the structural example of the optical pulse signal generation apparatus of 2nd Embodiment. It is a graph explaining the signal generation operation | movement in the optical pulse signal generation apparatus shown in FIG.

  Hereinafter, embodiments will be described with reference to the drawings. However, the embodiment described below is merely an example, and there is no intention to exclude application of various modifications and techniques not explicitly described in the embodiment. That is, the present embodiment can be implemented with various modifications without departing from the spirit of the present embodiment.

  Each drawing is not intended to include only the components shown in the drawings, and may include other components. Hereinafter, in the drawings, the same reference numerals denote the same or similar parts unless otherwise specified.

[A] First Embodiment [A-1] System Configuration Example FIG. 1 is a block diagram illustrating a configuration example of an optical pulse signal generation device according to a first embodiment.

  An optical pulse signal generation device (may be referred to as a “signal generation device”) 1 includes a CWLD 11, an SOA 12, a pulse generator 13, and a YDFA 14. “CWLD” is an abbreviation for “Continued Wave Laser Diode”. “SOA” is an abbreviation for Semiconductor Optical Amplifier. “YDFA” is an abbreviation for Ytterbium Doped Fiber Amplifier.

  The signal generation device 1 shown in FIG. 1 may be provided in, for example, a laser processing device such as a high-definition laser processing machine or a bioimaging device that can be applied in the biomedical field.

  The CWLD 11 is an example of a laser light source and outputs laser light. The CWLD 11 is a single oscillation mode semiconductor laser (LD) that outputs continuous light (CW), and may output single oscillation mode continuous light in a 1.06 μm band, for example. The CWLD 11 may be, for example, a DFB-LD (Distributed FeedBack-Laser Diode).

  Note that the laser beam output from the CWLD 11 is not limited to the single oscillation mode, and may be a multimode.

  The pulse generator 13 outputs an electrical pulse signal having a time width of at least sub-nanoseconds as a control signal at a predetermined period (for example, a period of 10 kHz to 10 MHz). The pulse generator 13 may output the electric pulse signal in a single shot, or may output the electric pulse signal in a quasi-periodic manner including a burst mode or the like. The pulse generator 13 may be referred to as a high speed electric pulse generator.

  The SOA 12 is configured as a semiconductor laser optical amplifier that generates optical pulses having a time width of at least sub-nanoseconds. That is, the SOA 12 receives the laser light from the CWLD 11 as an input signal, and generates a light pulse by receiving a control signal from the pulse generator 13 at the timing when the laser light is input (in other words, “Express”)). In this case, the electrical pulse signal from the pulse generator 13 is applied to the anode or cathode of the SOA 12. The output wavelength of the SOA 12 is the same as the output wavelength of the CWLD 11 and is, for example, 1.06 μm.

  In other words, the SOA 12 is applied with an electric pulse having a time width of at least sub-nanoseconds at an appropriate voltage value in a state where the laser beam from the CWLD 11 is input. As a result, the SOA 12 outputs an optical pulse having a time width of at least sub-nanoseconds. At this time, the peak value, pulse width, and pulse energy of the output light pulse are determined by the time change of carrier excitation in the SOA 12 and the stimulated emission action by the internal laser light.

  Thereby, it is possible to easily obtain an optical pulse having a time width of sub-nanoseconds or more with a simple configuration. Further, since the SOA 12 has not only a function for pulse excitation but also a function for optical amplification, the optical pulse signal can be efficiently amplified.

  The YDFA 14 is an example of an optical fiber amplifier, and is an optical amplifier that uses an ytterbium-doped fiber as a gain medium. The YDFA 14 receives the optical pulse input from the SOA 12 and amplifies and outputs the input optical pulse.

  The signal generation device 1 may include an optical fiber amplifier other than the YDFA 14 according to the characteristics of the CWLD 11. For example, when the output wavelength of the CWLD 11 is not in the 1.06 μm band, the signal generation device 1 may include an optical fiber amplifier other than the YDFA 14.

  FIG. 2 is a graph illustrating an outline of a signal waveform obtained by the optical pulse signal generation device 1 shown in FIG. In FIG. 2, the horizontal axis indicates time [picoseconds (ps)], and the vertical axis indicates intensity [a. u. ] Is shown.

  FIG. 2 shows an example of a time waveform of an optical pulse obtained when an electric pulse having a width of 600 ps is applied to the SOA 12. In the example shown in FIG. 2, approximately 2 mW of laser light is incident on the SOA 12, and the average transmitted light power is 0.1 μW in the absence of an electric pulse. On the other hand, the average optical output power when an electric pulse is input from the pulse generator 13 at a repetition period of 1 MHz is about 6 μW, and the obtained pulse energy is estimated to be about 6 pJ.

  Therefore, the peak power of the optical pulse is about 12 mW and is amplified by 8 dB with respect to the input optical power. The time width of the optical pulse output from the SOA 12 is about 440 ps (see reference signs A1 and A2 in FIG. 2).

  The optical pulse output from the SOA 12 may have a time width of at least sub-nanoseconds depending on the time width of the electric signal from the pulse generator 13 other than that shown in FIG.

  The electrical signal from the pulse generator 13 in the above embodiment is preferably an electrical signal having a sub-nanosecond to several nanosecond width, and the optical pulse signal output from the SOA 12 is preferably sub-nanosecond to It becomes an optical pulse signal with a width of several nanoseconds.

[A-2] Modification FIG. 3 is a block diagram illustrating a configuration example of an optical pulse signal generation device according to a modification of the first embodiment.

  The optical pulse signal generation device 1 according to the first embodiment illustrated in FIG. 1 includes one SOA 12, but an optical pulse signal generation device (which may be referred to as a “signal generation device”) 1a according to a modified example. Three SOAs 12 are provided.

  The signal generation device 1 shown in FIG. 3 may be provided in, for example, a laser processing device such as a high-definition laser processing machine or a bioimaging device that can be applied in the biomedical field.

  In the example shown in FIG. 1, each of the three SOAs 12 amplifies input laser light. A pulse generator 13 similar to that shown in FIG. 1 is connected to the SOA 12 at the last stage among the three SOAs 12, and as described above in the first embodiment, the SOA 12 transmits optical pulses having a time width of at least sub-nanoseconds. Generate.

  In the example shown in FIG. 3, the signal generation device 1a includes the three SOAs 12. However, the present invention is not limited to this, and the number of SOAs 12 included in the signal generation device 1a can be variously changed. . In addition, the electrical signal from the pulse generator 13 may be input as a control signal not to the last stage SOA 12 but to any one of the SOAs 12 before the last stage SOA 12, and further, from the pulse generator 13. Can be applied to each of the plurality of SOAs 12 as a control signal.

  By providing a plurality of SOAs 12, the laser light can be amplified more efficiently, and an optical pulse having a time width of at least a sub-nanosecond greater than a predetermined power (preferably, a sub-nanosecond to several nanosecond width) can be generated. it can.

[B] Second Embodiment FIG. 4 is a block diagram illustrating a configuration example of an optical pulse signal generation device according to a second embodiment.

  The optical pulse signal generation device (also referred to as “signal generation device”) 2 of the second embodiment is in addition to the SOA 12, the pulse generator 13, and the YDFA 14 of the first embodiment shown using FIG. A pulse generator 21 is provided, and a pulse LD 22 is provided instead of the CWLD 11 of the first embodiment shown in FIG.

  The signal generation device 1 shown in FIG. 4 may also be provided in, for example, a laser processing device such as a high-definition laser processing machine or a bioimaging device that can be applied in the biomedical field.

  The pulse generator 21 is connected to the pulse LD 22 and outputs an electric pulse signal having a predetermined period (for example, a period of 10 kHz to 10 MHz) and a time width longer than the sub-nanosecond width as a control signal. Applied to the pulse LD22. The pulse generator 13 may output the electric pulse signal in a single shot, or may output the electric pulse signal in a quasi-periodic manner including a burst mode or the like. Again, this electrical pulse signal is applied to the anode or cathode of the pulse LD22. The pulse generator 13 may be referred to as a high speed electric pulse generator.

  The pulse LD 22 is an example of a laser light source and outputs laser light. The pulse LD 22 is a single oscillation mode semiconductor laser (LD) that outputs pulsed light, and may output, for example, 1.06 μm band single oscillation mode pulsed light. The pulse LD22 may be a DFB-LD, for example.

  The laser beam output from the pulse LD 22 is not limited to the single oscillation mode, and may be a multimode.

  FIG. 5 is a graph for explaining a signal generation operation in the signal generation device 2 shown in FIG. In FIG. 5, the horizontal axis represents time, and the vertical axis represents intensity in arbitrary units [a. u. ] Is shown.

  Reference numeral B1 in FIG. 5 indicates an optical pulse signal output by the pulse LD22. The pulse LD 22 receives the input of the first electric pulse signal from the pulse generator 21, thereby causing the first pulse component (see reference B 11 in FIG. 5) and the subsequent component of the first pulse component B 11 (pulse subsequent component: FIG. 5). The optical pulse signal B1 is output. Here, the time width of the first electric pulse signal is about the time width of the time width TB11 of the first pulse component B11 and the time width TB12 of the pulse subsequent component B12, and depends on this time width (TB11 + TB12). It has become a thing.

  The laser beam output from the pulse LD 22 is not limited to the single oscillation mode, and may be a multimode.

  The pulse generator 13 is electrically synchronized with the pulse generator 21 and generates a second electric pulse signal having a sub-nanosecond width shorter than the time of the pulse subsequent component B12 in a predetermined cycle (for example, a cycle of 10 kHz to 10 MHz). A control signal is input to the SOA 12. The pulse generator 13 may output the electric pulse signal in a single shot, or may output the electric pulse signal in a quasi-periodic manner including a burst mode or the like.

  Reference sign B <b> 2 in FIG. 5 indicates a second electric pulse signal output by the pulse generator 13. The second electric pulse signal output from the pulse generator 13 is generated at the timing when the pulse subsequent component B12 is input from the pulse LD22 (see reference numeral TB12 in FIG. 5), as indicated by reference numeral B2.

  The SOA 12 receives the optical pulse signal B1 from the pulse LD22 as an input signal. Further, the SOA 12 has the pulse subsequent component B12 at the timing when the pulse subsequent component (see reference numeral B12 in FIG. 5) in the pulse signal is input in synchronization with the first electric pulse signal generated by the pulse generator 21. A second electric pulse signal having a time shorter than the sub-nanosecond width is received as a control signal. Then, the SOA 12 generates an optical pulse signal having a time longer than the sub-nanosecond width shorter than the time that the pulse subsequent component B12 has. The output wavelength of the SOA 12 is the same as the output wavelength of the pulse LD 22 and is, for example, 1.06 μm.

  The optical pulse signal generated by the SOA 12 has the same characteristics as the optical pulse signal generated in the first embodiment shown in FIG.

  In the second embodiment, the same effects as those of the first embodiment described above can be obtained, and the following effects can be obtained.

  That is, an optical pulse having a sub-nanosecond width or more is generated by the pulse LD 22 and incident on the SOA 12, and the SOA 12 is electrically pulsed in time with the temporally flat portion (pulse subsequent component B 12) of the incident optical pulse. In most cases, the laser beam does not enter the SOA 12, thereby suppressing light leakage when the SOA 12 is not excited. Further, the ON / OFF optical power ratio of the SOA 12 can be greatly improved.

  In the above embodiment, the electrical signal from the pulse generator 21 is preferably an electrical signal having a width of several nanoseconds or more, and the optical pulse signal from the pulse LD 22 is preferably several nanoseconds or more in accordance with this. It becomes an optical pulse signal. The electrical signal from the pulse generator 13 is preferably an electrical signal having a sub-nanosecond to several nanosecond width, and the optical pulse signal output from the SOA 12 is preferably an optical pulse having a sub-nanosecond to several nanosecond width. Signal.

[C] Others The disclosed technology is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of each embodiment. Each configuration and each process of each embodiment can be selected as necessary, or may be appropriately combined.

  For example, the signal generation device 2 of the second embodiment shown in FIG. 4 may include a plurality of SOAs 12 as in the signal generation device 1a of the modification of the first embodiment shown in FIG. In this case, the number of SOAs 12 included in the signal generation device 2 can be variously changed. In addition, the electrical signal from the pulse generator 13 (time width is preferably sub-nanosecond to several nanoseconds) is input as a control signal not to the last stage SOA 12 but to any one of the SOAs 12 before the last stage SOA 12. In addition, the electric signal from the pulse generator 13 (the time width is preferably sub-nanosecond to several nanoseconds) can be applied to the plurality of SOAs 12 as a control signal.

  The signal generation device 2 may also be included in a laser processing machine such as a high-definition laser processing machine or a bioimaging apparatus that can be applied in the biomedical field.

1, 1a, 2 Optical pulse signal generator 11 CWLD
12 SOA
13,21 Pulse generator 14 YDFA
22 pulse LD

The technology described in this specification includes an optical pulse signal generation device, a laser processing device, and a bioimage.
On di packaging equipment.

Claims (8)

A laser light source;
By receiving laser light from the laser light source as an input signal and receiving an electric pulse signal having a time width of sub-nanoseconds or more as a control signal at the timing when the laser light is input, light having a time width of sub-nanoseconds or more An optical pulse signal generation device comprising a semiconductor laser optical amplifier for generating a pulse signal. A laser light source composed of a single oscillation mode semiconductor laser that outputs continuous light;
A semiconductor laser optical amplifier that receives the continuous light from the laser light source as an input signal and generates an optical pulse signal having a time width of sub-nanoseconds or more by receiving an electric pulse signal having a time width of sub-nanoseconds or more as a control signal An optical pulse signal generation device characterized by comprising: By receiving the first electric pulse signal having a time width longer than sub-nanoseconds as a control signal, an optical pulse signal having a time width longer than sub-nanoseconds and including a first pulse component and a component subsequent to the first pulse component is output. A laser light source,
The optical pulse signal from the laser light source is received as an input signal, and the subsequent pulse of the first pulse component is synchronized with the first electric pulse signal at the timing when the subsequent component of the first pulse component is input. By receiving, as a control signal, a second electric pulse signal having a duration of sub-nanoseconds shorter than the time of the component, an optical pulse signal having a duration of sub-nanoseconds shorter than the time of the subsequent component of the first pulse component. An optical pulse signal generating device comprising a semiconductor laser optical amplifier for generating   4. The optical pulse signal generation device according to claim 1, wherein the laser light source is configured as a laser light source composed of a single oscillation mode semiconductor laser.   5. The optical pulse signal generation device according to claim 1, wherein another semiconductor laser optical amplifier is interposed between the laser light source and the semiconductor laser optical amplifier.   6. The optical pulse signal generator according to claim 1, wherein an optical fiber amplifier is connected to an output side of the semiconductor laser optical amplifier.   A laser processing apparatus comprising the optical pulse signal generation apparatus according to claim 1.   A bioimaging device comprising the optical pulse signal generation device according to claim 1.

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