CN111478173B - Passive Q-switched laser with 1.5 microns - Google Patents
Passive Q-switched laser with 1.5 microns Download PDFInfo
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- CN111478173B CN111478173B CN202010427059.4A CN202010427059A CN111478173B CN 111478173 B CN111478173 B CN 111478173B CN 202010427059 A CN202010427059 A CN 202010427059A CN 111478173 B CN111478173 B CN 111478173B
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- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/10—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
- H01S3/11—Mode locking; Q-switching; Other giant-pulse techniques, e.g. cavity dumping
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/09—Processes or apparatus for excitation, e.g. pumping
- H01S3/091—Processes or apparatus for excitation, e.g. pumping using optical pumping
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Abstract
The invention discloses a 1.5-micron passive Q-switched laser, which comprises N pumping sources with the same working period and working duty ratio, and a resonant cavity, a beam coupling device and a first optical fiber which are sequentially arranged at the light emitting sides of the N pumping sources; n pumping sources are used for sequentially emitting pumping light at fixed time intervals in a working period; the pulse width of the pumping source is equal to the fixed time interval; the resonant cavity is used for pumping the laser crystals in the resonant cavity by using N pump lights to obtain N beams of 1.5-micrometer lasers emitted from different positions of the laser crystals, and each beam of laser is emitted after being reflected for multiple times in the resonant cavity; the beam coupling device is used for coupling the N laser beams emitted from the resonant cavity into the first optical fiber to form single-path laser; and the first optical fiber is used for transmitting and emitting the single-path laser. The 1.5-micrometer passive Q-switched laser can output continuous pulse laser in a single path under the conditions of high peak power and chopping pumping, and effectively expands the application range of the 1.5-micrometer passive Q-switched laser.
Description
Technical Field
The application relates to a 1.5-micron passive Q-switched laser, and belongs to the technical field of lasers.
Background
With the continuous improvement of the automobile holding quantity in China and the continuous rising of the accident rate of automobile driving, the safety requirements of people on vehicle transportation are generally improved. The vehicle-mounted laser radar can effectively reduce the occurrence of automobile accidents by virtue of an excellent target detection technology, and is widely applied to an intelligent driving technology. The laser light source applied to the vehicle-mounted laser radar has the characteristics of high repetition frequency, narrow laser pulse, high peak power and the like. Passive Q-switching is a method commonly used to achieve high repetition rate, narrow pulse width, high peak power laser pulse output, and has the advantages of compact structure and small size, and therefore, is also commonly used as a laser light source for vehicle-mounted laser radars. The 1.5 micron laser radar is located in a human eye safe wave band, has good transmission performance on an atmospheric window, and has become a hot spot of research in the future as a vehicle-mounted laser radar light source.
In the prior art, a passive Q-switched laser pumps a laser crystal in a continuous pumping or chopping pumping mode, and a generated laser pulse sequence can be divided into a continuous pulse sequence and an intermittent pulse sequence distributed at a chopping frequency in a time domain. The laser pulse frequency output by the passively Q-switched laser is closely related to the peak power of the pump source, which typically needs to operate at high peak power in order to obtain high frequency pulse output. For a 1.5-micron laser crystal with poor laser thermal performance, in order to protect the laser crystal from being damaged, the pumping source can only pump the laser crystal in a chopping mode, so that the influence of the thermal effect of the laser crystal when the laser crystal is pumped by high power is reduced.
However, the laser pulse output by the chopped pump laser crystal is a series of discrete pulse sequences in the time domain, and the discontinuous pulse sequences increase the difficulty of using the laser as a light source and limit the application range of the laser.
Disclosure of Invention
The application aims to provide a 1.5-micrometer passive Q-switched laser to solve the technical problem that output laser pulses are discontinuous due to the fact that chopping pumping crystals exist in an existing 1.5-micrometer passive Q-switched laser.
The 1.5-micrometer passive Q-switched laser comprises N pumping sources with the same working period and working duty ratio, and a resonant cavity, a beam coupling device and a first optical fiber which are sequentially arranged on the light emitting sides of the N pumping sources;
the N pumping sources are used for sequentially emitting pumping light at fixed time intervals in one working cycle; the pulse width of the pumping source is equal to the fixed time interval;
the resonant cavity is used for pumping the laser crystal in the resonant cavity by using N pump lights to obtain N beams of 1.5-micrometer lasers emitted from different positions of the laser crystal, and each beam of laser is emitted after being reflected for multiple times in the resonant cavity;
the beam coupling device is used for coupling the N laser beams emitted from the resonant cavity into the first optical fiber to form single-path laser;
the first optical fiber is used for transmitting and emitting the single-path laser.
Preferably, the optical beam coupling apparatus comprises N coupling devices;
the N coupling devices are respectively arranged on light paths of N laser beams emitted from the resonant cavity and are used for respectively coupling the laser beams into the first optical fiber to form a single laser beam;
preferably, the coupling device is a micro-convex lens or a waveguide.
Preferably, the optical beam coupling apparatus includes N coupling devices, N second optical fibers, and one optical fiber coupler;
the N coupling devices and the N second optical fibers are respectively and sequentially arranged on the light path of the N laser beams emitted from the resonant cavity; the N coupling devices correspond to the N second optical fibers one by one;
the coupling device is used for coupling the corresponding laser into the corresponding second optical fiber;
the second optical fiber for transmitting the laser light coupled thereto;
the optical fiber coupler is used for coupling the laser in the N second optical fibers to the first optical fiber to form a single laser.
Preferably, the device further comprises a signal feedback system and a beam splitter arranged between the resonant cavity and the beam coupling device;
the beam splitting piece is used for reflecting one part of each laser beam emitted from the resonant cavity to the signal feedback system, and transmitting the other part of each laser beam to the beam coupling device;
and the signal feedback system is used for monitoring the distribution condition of each laser beam emitted from the resonant cavity in a time domain and adjusting the light emitting sequence of the N pumping sources according to the distribution condition.
Preferably, said N is determined according to a first formula; the first formula is:
N＝1/D
in the formula, N is the number of the pumping sources, and D is the working duty ratio of the pumping sources;
preferably, the fixed time interval is determined according to a second formula; the second formula is:
ΔT＝D×T
in the formula, Δ T is a fixed time interval, D is a duty cycle of the pump source, and T is a duty cycle of the pump source.
Preferably, the laser crystal is Er3+/Yb3+Double-doped borate crystal and Er3+/Yb3+Double doped vanadate crystals or Er3+/Yb3+One of double-doped yttrium aluminum garnet crystals.
Preferably, the pump light emitted by the N pump sources is incident to different positions of the laser crystal in a dispersed form;
preferably, N of the pump sources are arranged in an array.
Preferably, the optical fiber laser further comprises a coupling lens group arranged between the N pumping sources and the resonant cavity;
the coupling lens group is used for adjusting the radius of the pump light incident to the laser crystal;
preferably, the coupling lens group includes two convex lenses coaxially and arranged with convex surfaces facing each other.
Preferably, the optical fiber coupling device further comprises a light splitting route arranged between the N pumping sources and the coupling lens group;
and the light splitting route is used for separating the pumping light emitted by the N pumping sources.
Preferably, the resonant cavity comprises a pump mirror, a laser crystal and a coupling output mirror which are arranged in sequence;
the pump mirror is used for transmitting the pump light and reflecting the laser emitted from the laser crystal;
the laser crystal converts the pump light transmitted by the pump mirror into laser and enhances the intensity of the laser incident to the laser crystal;
and the coupling output mirror is used for reflecting and partially transmitting the laser emitted from the laser crystal, and the transmitted laser is pulse laser.
Compared with the prior art, the passive Q-switched laser with the diameter of 1.5 microns has the following beneficial effects:
the 1.5 micron passive Q-switched laser is provided with N pumping sources with the same working period and working duty ratio, so that output pulse lasers are mutually superposed, and a single-path output continuous pulse laser is obtained by combining the light beam coupling device and the first optical fiber, so that the defect that the laser pulse output by the traditional 1.5 micron passive Q-switched laser is discontinuous under the conditions of high peak power and chopping pumping is overcome, the output laser pulse is continuous in a time domain under the working condition of the chopping pumping, and the output continuous pulse laser is ensured to be output from the same conduction device at the same time.
In order to realize that the N laser beams emitted from the resonant cavity can be coupled to different positions of the first optical fiber, the light beam coupling device comprises N coupling devices, and the coupling devices are preferably micro convex lenses or waveguides.
In order to reduce the power loss in the laser transmission process, the light beam coupling device comprises N coupling devices, N second optical fibers and an optical fiber coupler, the second optical fibers respectively transmit the laser beams, and then the laser beams are coupled into the same first optical fiber at the port close to the laser emergent port.
Because of the influence of the irradiation of the pumping light, the internal part of the laser crystal can accumulate heat load to generate heat effect, and the serious heat effect can greatly influence the quality of the pulse laser. Through the setting, the heat effect condition inside the laser crystal can be effectively avoided.
In order to ensure that the light output by the pump light pumping laser crystal is 1.5 microns laser, the invention limits the laser crystal to Er3+/Yb3+Double-doped borate crystal and Er3+/Yb3+Double doped vanadate crystals or Er3+/Yb3+One of double-doped yttrium aluminum garnet crystals. The three types of laser crystals have small conversion loss, and the quality of laser output is ensured.
The invention also provides a coupling lens group which is used for focusing the pump light at different positions of the laser crystal in the resonant cavity and avoiding the influence of the thermal effect of the crystal on each path of pump source.
In order to avoid mutual influence among the pump lights generated by N pump sources, the invention is provided with a light splitting route which separates each pump light path through a mechanical structure.
Drawings
FIG. 1 is a schematic structural diagram of a 1.5 μm passively Q-switched laser according to the present invention;
FIG. 2 is a schematic structural diagram of a passive Q-switched laser of 1.5 μm according to an embodiment of the present invention;
FIG. 3 is a pulse sequence chart of the output laser of the passive Q-switched laser of 1.5 μm in the embodiment of the present invention;
fig. 4 is a sequence diagram of the output laser of a prior art 1.5 μm passive Q-switched laser under continuous pumping and chopping pumping conditions.
List of parts and reference numerals:
1. a first pump source; 2. a second pump source; 3. a third pump source; 4. a fourth pump source; 5. a fifth pump source; 6. a light splitting route; 7. a first convex lens; 8. a second convex lens; 9. a pump mirror; 10. a laser crystal; 11. a coupling output mirror; 12. a light splitting sheet; 13. a signal monitoring system; 14. a signal modulation system; 15. a multi-channel pumping system; 16. a signal feedback system; 17. a beam coupling system; 18. a beam coupling device; 19. a first optical fiber; 20. a second optical fiber; 21 a fiber coupler.
Detailed Description
In the prior art, a 1.5-micron passive Q-switched laser pumps a laser crystal in a continuous pumping or chopping pumping mode, and a generated laser pulse sequence can be divided into a continuous pulse sequence and an intermittent pulse sequence distributed at a chopping frequency in a time domain, as shown in fig. 4, wherein an abscissa is time, a unit is second, and an ordinate is normalized signal intensity. In fig. 4, (a) shows a continuous pump light, and the output pulse laser light is (c); in fig. 4, (b) shows chopped pump light, and the output pulse laser light is (d). It can be seen that the pump light generated by a single pump source can cause the output pulsed laser to be intermittent. In order to overcome the problems of chopping pumping, the application improves a 1.5-micrometer passive Q-switched laser.
The present invention will be described in detail with reference to examples, but the present invention is not limited to these examples.
As shown in fig. 1 and fig. 2, the 1.5 μm passive Q-switched laser according to the embodiment of the present invention includes a multi-pump system 15, where the multi-pump system 15 includes N pump sources having the same duty cycle and duty cycle. The laser also comprises a resonant cavity and a beam coupling system 17 which are sequentially arranged at the light-emitting sides of the N pumping sources, wherein the beam coupling system 17 comprises a beam coupling device 18 and a first optical fiber 19, and the beam coupling device 18 and the first optical fiber 19 are sequentially arranged at the light-emitting sides of the resonant cavity; n pumping sources for sequentially emitting pumping light at fixed time intervals in one working cycle; the pulse width of the pumping source is equal to the fixed time interval; the pump source in the embodiments of the present invention is preferably a semiconductor pump source and is a pump source that pumps a crystal in a chopped pump mode of operation.
According to the resonant cavity, N pump lights are utilized to pump different positions of the laser crystal in the resonant cavity to obtain a plurality of beams of 1.5-micrometer lasers emitted from different positions of the laser crystal, and each beam of laser is emitted after being reflected for a plurality of times in the resonant cavity.
The beam coupling device 18 of the present invention is used for coupling the N laser beams emitted from the resonant cavity into the first optical fiber 19 to form a single laser beam;
and a first optical fiber 19 for transmitting and emitting the single laser light.
The 1.5 micron passive Q-switched laser is provided with N pumping sources with the same working period and working duty ratio, so that output pulse lasers are mutually superposed, and a single-path output continuous pulse laser is obtained by combining the light beam coupling device and the first optical fiber, so that the defect that the laser pulse output by the traditional 1.5 micron passive Q-switched laser is discontinuous under the conditions of high peak power and chopping pumping is overcome, the output laser pulse is continuous in a time domain under the working condition of the chopping pumping, and the output continuous pulse laser is ensured to be output from the same conduction device at the same time.
In order to realize that the N laser beams emitted from the resonant cavity can be coupled to different positions of the first optical fiber 19, the beam coupling device 18 comprises N coupling devices, and the N coupling devices are respectively arranged on the light paths of the N laser beams emitted from the resonant cavity and are used for coupling the N laser beams into the first optical fiber 19 to form a single laser beam;
preferably, the coupling device is a micro-convex lens or a waveguide. The first optical fiber 19 in the present invention is a single mode optical fiber or a multimode optical fiber.
In order to reduce the power loss in the laser transmission process, the present application further improves the beam coupling apparatus 18, where the beam coupling apparatus 18 includes N coupling devices, N second optical fibers 20, and an optical fiber coupler 21; the N coupling devices and the N second optical fibers 20 are respectively and sequentially arranged on the light path of the N laser beams emitted from the resonant cavity; the N coupling devices correspond to the N second optical fibers 20 one to one; coupling means for coupling the respective laser light into the respective second optical fiber 20; a second optical fiber 20 for transmitting the laser light coupled thereto; and the optical fiber coupler 21 is used for coupling the laser light in the N second optical fibers 20 into the first optical fiber 19 to form single-path laser light. The second optical fiber 20 respectively conducts the laser beams, and then the laser beams are coupled into the same first optical fiber 19 near the port of the laser emergent port, so that the laser beams can be prevented from being exposed in the natural environment, the safety is improved, and the loss in the laser conduction process is reduced. The second optical fiber 20 is a single mode optical fiber or a multi-mode optical fiber.
Due to the influence of pump light irradiation, heat load can be accumulated in the laser crystal, so that a heat effect is generated, and the quality of the pulse laser is greatly influenced by a serious heat effect. When the crystal heat effect is serious, the frequency of the pulse laser will generate violent jitter, the frequency of the output pulse is not maintained at a certain fixed value any more, the superposition effect of each path of laser pulse is destroyed at the moment, and the pulse output of the laser will generate chaos and even enter a chaotic state. Therefore, the present invention also provides a signal feedback system 16 and a beam splitter 12 disposed between the resonant cavity and the beam coupling device 18;
the beam splitter 12 of the present invention is used for reflecting a part of each laser beam emitted from the resonant cavity to the signal feedback system 16, and transmitting the other part to the beam coupling device 18; and the signal feedback system 16 is used for monitoring the distribution condition of each laser beam emitted from the resonant cavity in a time domain and adjusting the light emitting sequence of the N pumping sources according to the distribution condition. The present invention utilizes the signal feedback system 16 to determine the distribution of the pulse laser outputted by each pump source in the time domain. When the frequency of a certain path of pulse laser is found to be jittered, the pumping sequence of each path of pumping source can be adjusted, and the light emitting sequence of the pumping source with the jittering pulse laser is delayed, so that the heat influence between adjacent pumped parts of the laser crystal is reduced to the minimum, and the pulse superposition effect is ensured.
In order to realize the optimal continuous work of the N pump sources in one working period, the number of the pump sources and the light-emitting time interval of the adjacent pump sources need to be limited. The invention limits the number of the pumping sources, and the number of the pumping sources is determined according to a first formula; the first formula is:
N＝1/D
in the formula, N is the number of the pumping sources, and D is the duty cycle of the pumping sources. The value of N should satisfy: 1/N is a rational number value, which can be beneficial to a signal feedback system to analyze and process signals.
The invention also defines a fixed time interval, which is determined according to a second formula: the second formula is:
ΔT＝D×T
in the formula, Δ T is a fixed time interval, D is a duty cycle of the pump source, and T is a duty cycle of the pump source.
In the invention, to obtain 1.5 micron laser, the laser crystal is set as Er3+/Yb3+Double-doped borate crystal and Er3+/Yb3+Double doped vanadate crystals or Er3+/Yb3+One of double-doped yttrium aluminum garnet crystals. Wherein, Er3+/Yb3+The double-doped borate crystal comprises Er, Yb, YAB, Er, Yb, GdAB and Er, Yb and LuAB; er3+/Yb3+The double-doped vanadate crystal comprises Er, Yb and YVO4；Er3+/Yb3+The double-doped yttrium aluminum garnet crystal comprises Er, Yb and YAG; the laser crystal has small conversion loss, and the quality of laser output is ensured.
Due to the influence of pump light irradiation, heat load can be accumulated in the laser crystal, so that a heat effect is generated, and the quality of the pulse laser is greatly influenced by a serious heat effect. Therefore, the invention limits the pump light emitted by the N pump sources to be incident to different positions of the laser crystal in a dispersed form, avoids the heat load accumulation of the same position and ensures the quality of the pulse laser.
Furthermore, N pumping sources are arranged in an array; the pumping light emitted by the N pumping sources is incident to different positions of the laser crystal in an array form, so that the heat influence between adjacent pumped parts of the laser crystal is ensured to be minimum, and the pulse laser superposition effect is ensured.
In order to shape the pump light and focus the pump light on the laser crystal, and avoid the loss of the pump light, the invention sets up the coupling lens group between N pumping sources and resonant cavity; and the coupling lens group is used for adjusting the radius of the pump light incident to the laser crystal. In this embodiment, the coupling lens group includes a first convex lens 7 and a second convex lens 8, which are coaxial and have convex surfaces facing each other. Wherein the first convex lens 7 and the second convex lens 8 are preferably plano-convex lenses, and the focusing effect of the plano-convex lenses is better.
In order to avoid mutual influence of the pump light emitted by the N pump sources, a light splitting route 6 is arranged between the N pump sources and the coupling lens group; the optical splitting path 6 separates the pump lights by mechanical parts, and does not affect each other.
In order to generate pulse laser, the resonant cavity provided by the invention comprises a pump mirror 9, a laser crystal 10 and a coupling output mirror 11 which are sequentially arranged;
the pump mirror 9 is used for transmitting pump light and reflecting laser light emitted from the laser crystal 10; a laser crystal 10 converting the pump light transmitted through the pump mirror into laser light and enhancing the intensity of the laser light incident to the laser crystal 10; and the coupling output mirror 11 is used for reflecting part of laser light emitted from the laser crystal 10 and transmitting the other part of the laser light, and the transmitted laser light is pulse laser light.
To illustrate the 1.5 micron passively Q-switched laser of the present invention in more detail, specific examples will be described below.
The structure of the 1.5-micron passive Q-switched laser in this example is schematically shown in FIG. 2, the operating frequency of the semiconductor pump source is 20Hz, the operating period is 0.05 seconds, and the operating duty cycle is 0.2. The required number of the pump sources is 5 (including the first pump source 1, the second pump source 2, the third pump source 3, the fourth pump source 4 and the fifth pump source 5) calculated according to the first formula and the second formula, and the 5 pump sources sequentially emit light to the resonant cavity at a time interval of 0.01 second. After passing through the light splitting route 6 and the first convex lens 7 and the second convex lens 8 in the coupling lens group, the pump light emitted by each pump source is focused and irradiated on different positions of the laser crystal 10 by the pump mirror 9. Wherein the laser crystal 10 is Er, Yb and YAB, or Er, Yb and GdAB, Er, Yb and LuAB, Er, Yb and YVO4Or Er, Yb and YAG. The 5 paths of pump sources respectively irradiate 5 different positions of the laser crystal 10, and laser output light paths generated by each path of pump source are mutually independent and do not interfere with each other; the pulsed lasers corresponding to the first pump source 1, the second pump source 2, the third pump source 3, the fourth pump source 4 and the fifth pump source 5 are A, B, C, D, E respectively.
Fig. 3 shows a pulse sequence of the pulse laser obtained by the 5-way pump source, where (1) to (5) in fig. 3 are pulse lasers corresponding to the first pump source 1 to the fifth pump source 5, respectively, and (6) in fig. 3 is a pulse sequence of the laser emitted through the first optical fiber, where the abscissa is time, the unit is seconds, and the ordinate is normalized signal intensity. In the embodiment, since the duty cycle of the pump source is 0.2, the pulse exists in 0.05 second (1/(20Hz)) of one period, and only in 0.01 second. At this time, the timing of the 5-channel pulse laser is monitored in real time by the signal feedback system 16. The signal feedback system in this embodiment includes: a signal monitoring unit 13 and a signal modulation unit 14. The signal monitoring unit 13 is used for monitoring the distribution of all the pulse lasers in a time domain; the signal modulation unit 14 is used for adjusting the light emitting sequence of the N pumping sources according to the distribution situation, so that the pulses are staggered from each other by 0.01 second, and the sequence of each path of laser pulse is obtained as follows:
when only the first pump source 1 is operated, the pump light irradiates to the position A of the laser crystal 10, and the pulse laser A is emitted from the position A. The pulse sequence is shown as (1) in fig. 3.
When only the second pump source 2 is operated, the pump light irradiates to the position B of the laser crystal 10, and the pulse laser B is emitted from the position B. The pulse sequence is shown in (2) of fig. 3, and the time interval between the pulse and the pulse at a is 0.01 second.
When only the third pump source 3 is operated, the pump light irradiates to the position C of the laser crystal 10, and the pulse laser C is emitted from the position C. The pulse sequence is shown as (3) in fig. 3. The time interval between the pulse and the pulse at B is 0.01 second.
When only the fourth pump source 4 is operated, the pump light is irradiated to the position D of the laser crystal 10, and the pulsed laser light D is emitted from the position D. The pulse sequence is shown as (4) in fig. 3. The time interval between the pulse and the pulse at C is 0.01 second.
When only the fifth pump source 5 is operated, the pump light is irradiated to the position E of the laser crystal 10, and the pulsed laser light E is emitted from the position E. The pulse sequence is shown as (5) in fig. 3. The time interval between the pulse and the pulse at D is 0.01 second.
After the 5 pumping sources are adjusted by the signal feedback system 16, 5 lasers are obtained at the output rear end of the beam splitter 12, and the 5 lasers are respectively emitted sequentially through the coupling device, the second optical fiber and the first optical fiber to obtain a passive Q-switched pulse sequence diagram of the present invention, as shown in (6) in fig. 3. The pulses are distributed continuously in the time domain, and the distribution of the pulse sequence is consistent with that of the continuous pumping. Therefore, the 1.5-micron passive Q-switched laser can still obtain continuous pulse laser even under the condition that the pump source is in chopping operation.
Although the present application has been described with reference to a few embodiments, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the application as defined by the appended claims.
Claims (14)
1. A1.5-micron passive Q-switched laser is characterized by comprising N pumping sources with the same working period and working duty ratio, and a resonant cavity, a beam coupling device and a first optical fiber which are sequentially arranged at the light emitting sides of the N pumping sources;
the N pumping sources are used for sequentially emitting pumping light at fixed time intervals in one working cycle; the pulse width of the pumping source is equal to the fixed time interval;
the resonant cavity is used for pumping the laser crystal in the resonant cavity by using N pump lights to obtain N beams of 1.5-micrometer lasers emitted from different positions of the laser crystal, and each beam of laser is emitted after being reflected for multiple times in the resonant cavity;
the beam coupling device is used for coupling the N laser beams emitted from the resonant cavity into the first optical fiber to form single-path laser;
the first optical fiber is used for transmitting and emitting the single-path laser.
2. The 1.5 μm passively Q-switched laser according to claim 1, wherein the beam coupling means comprises N coupling devices;
the N coupling devices are respectively arranged on light paths of the N laser beams emitted from the resonant cavity and used for coupling the N laser beams into the first optical fiber to form a single laser beam.
3. The 1.5 μm passive Q-switched laser according to claim 1, wherein the beam coupling means comprises N coupling devices, N second optical fibers and one fiber coupler;
the N coupling devices and the N second optical fibers are respectively and sequentially arranged on the light path of the N laser beams emitted from the resonant cavity; the N coupling devices correspond to the N second optical fibers one by one;
the coupling device is used for coupling the corresponding laser into the corresponding second optical fiber;
the second optical fiber for transmitting the laser light coupled thereto;
the optical fiber coupler is used for coupling the laser in the N second optical fibers to the first optical fiber to form a single laser.
4. The 1.5 μm passive Q-switched laser according to claim 1, further comprising a signal feedback system and a beam splitter disposed between the resonator and the beam coupling device;
the beam splitting piece is used for reflecting one part of each laser beam emitted from the resonant cavity to the signal feedback system, and transmitting the other part of each laser beam to the beam coupling device;
and the signal feedback system is used for monitoring the distribution condition of each laser beam emitted from the resonant cavity in a time domain and adjusting the light emitting sequence of the N pumping sources according to the distribution condition.
5. The 1.5 micron passively Q-switched laser of claim 1, wherein N is determined according to a first formula; the first formula is:
N＝1/D
in the formula, N is the number of the pumping sources, and D is the working duty ratio of the pumping sources.
6. The 1.5 μm passive Q-switched laser according to claim 1, wherein the laser crystal is Er3+/Yb3+Double-doped borate crystal and Er3+/Yb3+Double doped vanadate crystals or Er3+/Yb3+One of double-doped yttrium aluminum garnet crystals.
7. The 1.5 μm passive Q-switched laser according to claim 1, wherein the pump light emitted by the N pump sources is incident on different positions of the laser crystal in a dispersed manner.
8. The 1.5 μm passive Q-switched laser according to claim 1, further comprising a coupling lens group disposed between the N pump sources and the resonator;
and the coupling lens group is used for adjusting the radius of the pump light incident to the laser crystal.
9. The 1.5 μm passive Q-switched laser according to claim 8, further comprising a beam splitting route disposed between the N pump sources and the coupling lens group;
and the light splitting route is used for separating the pumping light emitted by the N pumping sources.
10. The 1.5-micrometer passive Q-switched laser according to any one of claims 1-9, wherein the resonant cavity comprises a pump mirror, a laser crystal and a coupling output mirror which are arranged in sequence;
the pump mirror is used for transmitting the pump light and reflecting the laser emitted from the laser crystal;
the laser crystal converts the pump light transmitted by the pump mirror into laser and enhances the intensity of the laser incident to the laser crystal;
and the coupling-out mirror is used for reflecting and partially transmitting the laser light emitted from the laser crystal.
11. A 1.5 μm passive Q-switched laser according to claim 2 or 3, wherein the coupling device is a micro-convex lens or a waveguide.
12. The 1.5 μm passively Q-switched laser according to claim 1, wherein the fixed time interval is determined according to a second formula; the second formula is:
ΔT＝D×T
in the formula, Δ T is a fixed time interval, D is a duty cycle of the pump source, and T is a duty cycle of the pump source.
13. The 1.5 μm passive Q-switched laser according to claim 1, wherein N pump sources are arranged in an array.
14. The 1.5 μm passive Q-switched laser according to claim 8, wherein the coupling lens group comprises two convex lenses coaxially arranged with their convex surfaces facing each other.
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| CN202010427059.4A Active CN111478173B (en) | 2020-05-19 | 2020-05-19 | Passive Q-switched laser with 1.5 microns |
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1714318A (en) * | 2001-03-12 | 2005-12-28 | 电子科学工业公司 | Quasi-CW diode-pumped, solid-state UV laser system and method employing same |
| CN110932069A (en) * | 2019-05-09 | 2020-03-27 | 长春理工大学 | Ultrahigh repetition frequency narrow pulse single-wavelength alternate Q-switched laser output method and laser |
| CN111029893A (en) * | 2019-05-09 | 2020-04-17 | 长春理工大学 | Dual-wavelength alternate Q-switching single longitudinal mode output group pulse laser and laser output method |
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| US20080273559A1 (en) * | 2007-05-04 | 2008-11-06 | Ekspla Ltd. | Multiple Output Repetitively Pulsed Laser |
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1714318A (en) * | 2001-03-12 | 2005-12-28 | 电子科学工业公司 | Quasi-CW diode-pumped, solid-state UV laser system and method employing same |
| CN110932069A (en) * | 2019-05-09 | 2020-03-27 | 长春理工大学 | Ultrahigh repetition frequency narrow pulse single-wavelength alternate Q-switched laser output method and laser |
| CN111029893A (en) * | 2019-05-09 | 2020-04-17 | 长春理工大学 | Dual-wavelength alternate Q-switching single longitudinal mode output group pulse laser and laser output method |
Non-Patent Citations (1)
| Title |
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| Yujin Chen等.Continuously diode-pumped passively -switched eye-safe 1537 nm Er:Yb:Lu2Si2O7 pulse laser.《OPTICS LETTERS》.2020,第45卷(第6期),第1575-1578页. * |
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