CN218472525U

CN218472525U - Raman fiber laser with continuously adjustable pulse width range

Info

Publication number: CN218472525U
Application number: CN202222577719.4U
Authority: CN
Inventors: 王禹凝; 郑权; 宋国龙; 张智威; 张秀齐; 赵岭
Original assignee: Changchun New Industries Optoelectronics Tech Co ltd
Current assignee: Changchun New Industries Optoelectronics Tech Co ltd
Priority date: 2022-09-28
Filing date: 2022-09-28
Publication date: 2023-02-10
Anticipated expiration: 2032-09-28

Abstract

The utility model relates to a pulse wide range continuously adjustable's raman fiber laser, its characterized in that: the Raman laser seed source outputs nanosecond pulses, a relay of three-out-of-one starts a trigger signal to provide a duty ratio frequency signal to a logic gate circuit and a time delay device, and then the duty ratio frequency signal is input into an analog switch high-frequency large-current laser driver, the high-frequency large-current laser driver is provided with 6 channels, six channels are connected in parallel to drive a Raman laser seed source laser, and the Raman laser seed source laser is amplified by a Raman laser amplifier; the Raman laser seed source is a 1178nm semiconductor LD with high beam quality or a wavelength LD within the range of 1-2 μm; the corresponding pulse width parameters can be set according to different processing materials, so that one laser can meet the processing requirements of most of materials with different materials.

Description

Raman fiber laser with continuously adjustable pulse width range

Technical Field

The utility model relates to a pulse wide range continuously adjustable's raman fiber laser belongs to laser technical field.

Background

A laser is a device capable of emitting laser light. The first microwave quantum amplifier was made in 1954, and a highly coherent microwave beam was obtained. The first ruby laser was made by t.h. meiman et al in 1960, a.l. xiaoloo and c.h. tiss, which popularized the microwave quantum amplifier principle to the optical frequency range in 1958. He-ne lasers were made by a. Jiawen et al in 1961. In 1962, a gallium arsenide semiconductor laser was created by r.n. hall et al. Later, the variety of lasers has been increasing. According to the working medium, the laser can be classified into a gas laser, a solid laser, a semiconductor laser and a dye laser 4. Free electron lasers have also been developed recently, with high power lasers typically being pulsed outputs.

The existing pulse Raman fiber laser structure can be divided into a Q-switched Raman fiber laser and a MOPA Raman fiber laser, wherein a MOPA (Master Oscillator Power-Amplifier) main oscillation Power Amplifier is coupled into a gain fiber by seed signal light and pump light with high beam quality, so that the high-Power output of a seed source is realized, and the frequency pulse width of the output light of the seed source is consistent with that of the seed signal light.

A single nanosecond-adjustable MOPA structure Raman fiber laser in the current market is limited in processing materials, some materials need nanosecond Raman lasers for high energy and heat, some materials need picosecond Raman lasers for heat-sensitive materials and materials needing high peak power, and the conventional MOPA Raman fiber laser cannot well meet market demands.

Disclosure of Invention

An object of the utility model is to provide a pulse wide region continuously adjustable's raman fiber laser, it is that trigger signal derives to realize by picosecond to microsecond pulse width adjustable MOPA structure raman fiber laser, can set up corresponding pulse width parameter according to different processing materials, makes a laser can satisfy the processing demand of most different material materials.

The technical scheme of the utility model is realized like this: a Raman fiber laser with continuously adjustable pulse width is characterized in that: the pulse width range includes 1) 100ps to 5ns ultrashort fast pulse picosecond laser drive; 2) 5ns-1 mu s TTL signal high-frequency large-current laser drive; 3) The laser is driven by a constant current driven 100ns-1 mus arbitrary waveform laser; when the Raman laser seed source outputs nanosecond pulses, a relay selected from three relays starts a trigger signal to provide a certain duty ratio frequency signal, the rising edge of the frequency signal is identified for a logic gate circuit and a time delayer, nanosecond pulses with the frequency consistent with that of the trigger signal are generated and then input into an analog switch high-frequency large-current laser driver, the high-frequency large-current laser driver is provided with 6 channels, each channel can work at direct current up to 500 mA, six channels are connected in parallel to achieve the driving capability of the Raman laser seed source laser of 3A, and then the Raman laser seed source laser is amplified through a Raman laser amplifier; the Raman laser seed source generates nanosecond pulse light with the same frequency as the trigger signal, and is a 1178nm semiconductor LD with high beam quality or a wavelength LD within the range of 1-2 μm;

when the Raman laser seed source outputs picosecond pulses, a relay is selected to start a trigger signal to provide a frequency signal with a certain period, the signal rising edge is identified by an ultrashort fast pulse laser driver, picosecond pulses with the frequency consistent with that of the trigger signal are generated and output, the ultrashort fast pulse laser driver has the driving function of the Raman laser seed source laser, the laser driver is connected with external equipment through an SPI bus, parameters such as current, pulse width and the like are written into the driver, and the Raman laser seed source generates picosecond pulse light with the frequency identical with that of the trigger signal;

when the Raman laser seed source outputs any waveform pulse, a relay starting trigger signal is selected from three to add a differential amplification circuit after passing through a high-speed digital-to-analog converter, and a high-speed operational amplifier is matched with the differential amplification circuit, so that the amplification times of the circuit are adjusted, and any waveforms with different amplitudes are output and used as set points of a constant current circuit, so that the constant current circuit can rapidly modulate the peak power output by the laser, and the output of any waveform of the Raman laser seed source laser is realized.

The high-speed digital-to-analog converter is an 8-bit resolution product of a CMOS digital-to-analog converter (DAC), pins of the high-speed digital-to-analog converter are compatible with 10, 12 and 14-bit resolution products, the update rate of 125 MSPS is supported, differential current output is provided, a 1.2V on-chip reference voltage source and a reference voltage control amplifier are arranged in the high-speed digital-to-analog converter, data are written in the high-speed digital-to-analog converter in parallel through an FPGA or an MCU, the high-speed digital-to-analog converter outputs any desired voltage value, and output waveforms comprise sine waves, triangular waves or other waveforms.

The Raman laser seed source has low pulse output power and needs to be amplified in multiple stages by a Raman laser amplifier 11, an isolator is needed to be added between each stage of amplification to prevent return light from damaging a laser, and the TEC is matched for temperature control to enable the laser to output more stably at different temperatures, wherein the Raman laser amplifier comprises an isolator which is used for generating return light to damage a Raman laser seed source in the amplification process of the Raman laser seed source, a beam combiner adopts a structure of (2) × 1) and couples the light of the Raman laser seed source and pumping light into a gain fiber to amplify the power of the Raman laser seed source, the Raman gain fiber absorbs the pumping light and amplifies signal light generated by the Raman laser seed source, the amplified laser state is consistent with that of the Raman laser seed source, a filter contains the pumping light after amplification of the gain fiber, the filter can pump light by adding the filter at the output end to ensure the purity of the output laser, the Raman laser pumping source provides energy for the gain fiber to play an amplification effect on the seed source, the laser output selects different output modes according to different applications, and comprises jumper output, collimation and output of the isolation.

The utility model has the advantages that the range of the pulse modulation range ns of the common fiber laser is adjustable, and the laser realizes that the pulse width range is adjustable in 100ps-1us, the overall performance parameter of the Raman fiber laser is improved, a wider and more precise pulse width regulation mechanism can be adopted, corresponding pulse width parameters can be set according to different processing materials, one laser can meet the processing requirements of most of different materials, and the working modes of three lasers are provided, namely (a) the driving of 100ps to 5ns ultrashort fast pulse picosecond laser, (b) the driving of 5ns to 1 mus TTL signal high-frequency heavy current laser, (c) the driving of 100ns to 1 mus arbitrary waveform laser is realized by adopting a constant current driving mode; the working state of the seed source is changed, and finally, a seed source driving mode with randomly adjustable pulse width in the range from ps to us and randomly waved is realized.

Drawings

Fig. 1 is a schematic structural diagram of the present invention.

The device comprises a trigger signal 1, a logic gate circuit 2, a time delayer 3, a high-frequency large-current laser driver 4, an ultrashort fast pulse laser driver 5, a high-speed digital-to-analog converter 6, a differential amplification circuit 7, a constant current driving circuit 8, a one-out-of-three relay 9, a Raman laser seed source 10 and a Raman laser amplifier 11.

Fig. 2 is an optical structure of an enlarged portion of a raman laser.

Isolator 11-1, beam combiner 11-2, raman gain fiber 11-3, filter 11-4, raman pump source 11-5, and laser output 11-6.

Detailed Description

The invention is further described below with reference to the accompanying drawings: as shown in fig. 1: a Raman fiber laser with continuously adjustable pulse width range is characterized in that: the pulse width range includes 1) 100ps to 5ns ultrashort fast pulse picosecond laser drive; 2) 5ns-1 mus TTL signal high frequency large current laser drive; 3) The laser is driven by a constant current driven 100ns-1 mus arbitrary waveform laser;

when a system needs to output nanosecond pulses, a three-out-one relay 9 can select nanosecond pulses to be output structurally, a trigger signal 1 provides periodic signals (namely fixed frequency signals) with fixed duty ratios, the signals act on a logic gate circuit 2, the logic gate circuit integrates the incoming signals, the trigger signals in different modes can be converted into trigger signals needed by a time delayer 3 through the logic gate circuit, the trigger signal 1 output by the logic gate circuit 2 passes through the time delayer 3, the time delayer 3 delays the trigger signals to a certain extent and outputs the delayed signals in a reverse mode, the generated delay time is the pulse width of a Raman laser seed source, the delay time can be adjusted within 5ns-1us, the nanosecond pulse width of the Raman laser seed source is adjustable within 5ns-1us, the output capacity of the Raman laser seed source driven by the signals is slightly low, the Raman laser seed source needs to be driven by a high-frequency large-current laser driver 4, the high-frequency laser large-current driver 4 is a six-channel laser driver, and can realize non-switching spikes of a laser diode in a range of which the switching frequency is less than 200 MHz, six-channel fast switches can be independently controlled by TTL signals, and three-channel trigger signals can be input in an LVDS mode. Each channel can work under the direct current of 500 mA, six channels are connected in parallel to realize the driving capability of the 3A seed source laser, and the tunable pulse laser within the range of 5ns-1 mus can be output under the control of large current, thereby being convenient for Raman amplification.

When the system needs to output picosecond pulse width, the three-out-of-one relay 9 can select the structure output of the nano-picosecond pulse, similarly, the trigger signal 1 is provided to provide a periodic signal (namely a fixed frequency signal) with a fixed duty ratio, the signal acts on the ultrashort fast pulse laser driver 5 to generate a picosecond pulse width with a fixed frequency, the driver can control the pulse width to be adjustable within the range of 100ps to 5ns, the precision adjustment can be selected to be a wide-range coarse adjustment mode or a narrow-range fine adjustment mode, the coarse adjustment mode allows the pulse width to be configured by the step size of usually 250 ps, and each wide-range adjustment step size allows the adjustment by a finer small step size, so that the output of the picosecond pulse is ensured.

When the system wants to output any waveform, the one-out-of-three relay 9 can select the structural output of any pulse, similarly, the trigger signal 1 provides a periodic signal (namely a fixed frequency signal) with a fixed duty ratio, the signal directly acts on a 6 high-speed digital-to-analog converter, the high-speed digital-to-analog converter belongs to an 8-bit resolution product of a high-performance and low-power consumption CMOS digital-to-analog converter (DAC), pins are also compatible with 10, 12 and 14-bit resolution products, the updating rate of 125 MSPS is supported, differential current output is provided, and a 1.2V on-chip reference voltage source and a reference voltage control amplifier are arranged in the high-speed digital-to-analog converter. And data is written into the voltage regulator in parallel through the FPGA or the MCU, so that the voltage regulator outputs any desired voltage value. The change output voltage value of the high refresh rate is ensured, which can be regarded as a continuous signal quantization process, so that the output of any waveform can be obtained; a pin-compatible higher resolution DAC may also be selected to increase the smoothness of the output waveform. The high-speed digital-to-analog converter realizes that the pulse width is continuously adjustable in any shape from 100ns to 1 mu s through the control of an external trigger signal, the output of the waveform is sine wave, triangular wave or other waveforms, the differential amplifier circuit 7DAC is differential output, the differential amplifier circuit is added in a later stage, high-speed operational amplifier is adopted to match the differential amplifier circuit, the amplification factor of the circuit is adjusted, any waveform with different amplitudes is output, and the set point of the constant current drive circuit 8 is adjusted, so that the constant current circuit can rapidly modulate the peak power output by the laser, the output of any waveform of the seed source laser is realized, the high-speed digital-to-analog converter can drive the seed source of the laser to generate any wave pulse with high peak value to output by matching with the differential circuit, and the power of the laser is conveniently amplified.

The raman laser seed source 10 selects a high beam quality LD of 1178nm, or a wavelength LD in the range of 1-2 μm.

The power of the seed signal light is low so as to meet the requirement that the laser can be used for material processing, raman laser amplification needs to be carried out on a Raman laser seed source, and the performance that high power is needed needs to be amplified step by step so as to meet the requirement, namely, the MOPA Raman fiber pulse laser, the structure of a Raman laser amplifier 11 is shown in figure 2, the Raman laser seed source 10 ensures that return light generated in the amplification process of the seed source damages the seed source through an isolator 11-1, the beam combiner 11-2 generally adopts a structure of (2 + 1) < 1 >, the signal light of the seed source and the Raman pump light 11-3 are coupled into a gain fiber for power amplification of the seed source, the Raman gain fiber 11-4 absorbs the Raman pump light to amplify the signal light generated by the seed source, the amplified laser state is consistent with that of the seed source, the laser amplified laser state is amplified by the gain fiber, the laser is pure pump light amplified by the gain fiber, a filter 11-5 is added at the output end so as to strip redundant Raman pump light, the output of the output laser is ensured, the laser output 11-6 can be output in different collimation conditions, and the output modes can be selected according to different collimation conditions.

Different pulse width modes can be selected according to different materials, when materials such as plastics, glass, circuit boards and the like are subjected to micro-processing, the requirements on high peak value and low heat quantity of laser are met, the picosecond pulse mode can provide a deeper etching effect and a lower heat affected zone, and firstly, the picosecond laser mode is adopted; when materials such as stainless steel, aluminum alloy and the like are marked or derusted, the laser often has high heat and high average power requirements, and the nanosecond pulse width mode can provide high average power and ensure output of higher peak power, namely the nanosecond laser mode is firstly adopted; when the pulse of the laser seed source is a square wave, the leading edge of the pulse is preferentially amplified when the laser seed source is amplified, so that a spiked pulse is generated, the spiked pulse is not beneficial to generating high average power, and a nonlinear effect is easy to generate.

Claims

1. A Raman fiber laser with continuously adjustable pulse width range is characterized in that: the pulse width range includes 1) 100ps to 5ns ultrashort fast pulse picosecond laser drive; 2) 5ns-1 mus TTL signal high frequency large current laser drive; 3) The laser is driven by a constant current driven 100ns-1 mu s arbitrary waveform laser; the Raman laser seed source outputs nanosecond pulses, one of three relays starts a trigger signal to provide a frequency signal with a certain duty ratio, the rising edge of the frequency signal is identified through a logic gate circuit and a time delayer, nanosecond pulses with the frequency consistent with that of the trigger signal are generated and then input into a high-frequency large-current laser driver of an analog switch, the high-frequency large-current laser driver is provided with 6 channels, each channel can work at the direct current of up to 500 mA, and the six channels are connected in parallel to realize the driving capability of the Raman laser seed source laser of 3A and then are amplified through a Raman laser amplifier; the Raman laser seed source generates nanosecond pulse light with the same frequency as the trigger signal, and is a 1178nm semiconductor LD with high beam quality or a wavelength LD within the range of 1-2 μm;

the Raman laser seed source outputs picosecond pulses, a relay is selected to start a trigger signal to provide a frequency signal with a certain period, the signal rising edge is identified by an ultrashort fast pulse laser driver, picosecond pulses with the frequency consistent with that of the trigger signal are generated and output, the ultrashort fast pulse laser driver has the driving function of the Raman laser seed source laser, the laser seed source is connected with external equipment through an SPI bus, current and pulse width parameters are written into the driver, and the Raman laser seed source generates picosecond pulse light with the frequency identical with that of the trigger signal;

the Raman laser seed source outputs any waveform pulse, a relay starting trigger signal is selected from three, a differential amplifying circuit is added after passing through a high-speed digital-to-analog converter, high-speed operational amplification is matched with the differential amplifying circuit, the amplification times of the circuit are adjusted, and any waveforms with different amplitudes are output and used as set points of a constant current circuit, so that the constant current circuit can rapidly modulate the peak power output by the laser and output any waveforms of the Raman laser seed source laser.

2. The raman fiber laser of claim 1, wherein the high speed dac is an 8-bit resolution product of a CMOS dac, and the pins are also compatible with 10, 12, and 14-bit resolution products, and support the update rate of 125 MSPS, and a 1.2V on-chip reference voltage source and a reference voltage control amplifier are built in, and data is written in parallel to the high speed dac through the FPGA or the MCU, so that the high speed dac outputs any desired voltage value, and the output waveform includes sine wave, triangular wave, or other waveforms.

3. The raman fiber laser of claim 1, wherein the raman laser amplifier comprises an isolator, the beam combiner adopts a structure of (2 + 1) × 1, and couples the light of the raman laser seed source and the pump light into the gain fiber, the raman gain fiber absorbs the pump light and amplifies the signal light generated by the raman laser seed source, and the amplified laser state is consistent with the raman laser seed source.

4. The raman fiber laser of claim 1, wherein the time delay unit processes a pulsed laser that outputs a positive bandwidth of 5ns to 1 us; the high-frequency large-current laser driver is used for driving a laser seed source by an analog switch; the ultra-short fast pulse laser driver controls the pulse width to be adjustable within the range of 100ps to 5ns, the precision adjustment can be selected to be a wide-range coarse adjustment mode or a narrow-range fine mode, the coarse adjustment mode allows the pulse width to be configured with the step length of 250 ps generally, each wide-range adjustment step length allows the adjustment with finer small step length, and the output of picosecond pulses is ensured; the DAC is used for differential output; the constant current driving circuit rapidly modulates the peak power output by the laser, and the high-speed digital-to-analog converter drives the laser seed source to generate high-peak arbitrary wave pulse output by matching with the differential circuit; the raman laser seed source selects a high beam quality LD of 1178nm, or a wavelength LD in the range of 1-2 μm.