CN206236952U - Dual-wavelength synchronous pulsed fiber laser based on rare earth ion co-doped fiber - Google Patents

Abstract

The utility model is applied to laser technology field, there is provided a kind of dual wavelength lock-out pulse optical fiber laser based on rare earth ion co-doped fiber, including continuous light LD pumping sources, rare earth ion co-doped fiber resonant cavity, the continuous light LD pumping sources connect the resonator, and the rare earth ion co-doped fiber is located in resonator；Sensitized ions absorptive pumping light in the rare earth ion co-doped fiber, and a laser for wavelength is produced by sensitized ions radiation, meanwhile, by the laser that ionizing radiation produces another wavelength that is sensitized in the rare earth ion co-doped fiber；The saturable absorber being inserted into using the laser cavity radiated in sensitized ions, laser to sensitized ions radiation carries out adjusting Q or locked mode to be allowed to produce pulse laser, this Period Process has modulated the gain that is sensitized ionizing radiation laser and has produced synchronous pulse laser, so as to realize dual wavelength lock-out pulse optical fiber laser.The utility model provide device can integrated level it is high, it is possible to achieve all-fiber structure.

Description

Dual-wavelength synchronous pulsed fiber laser based on rare earth ion co-doped fiber

technical field

The utility model belongs to the field of laser technology, in particular to a dual-wavelength synchronous pulse fiber laser based on rare earth ion co-doped fiber.

Background technique

Dual-wavelength lasers have a wide range of applications in the generation of sum frequency/difference frequency, remote sensing, laser ranging, medical purposes, etc., especially dual-wavelength synchronous pulse laser has the advantages of large pulse energy and high peak power synchronous dual-wavelength pulse output , so that it has a better practical application effect. Compared with traditional solid-state lasers, fiber lasers have attracted much attention due to their outstanding advantages such as good heat dissipation, high conversion efficiency, low threshold, good beam quality, and easy integration. At present, there are three main methods of using fiber lasers to realize dual-wavelength synchronous pulse laser output:

1. Realize dual-wavelength synchronous Q-switching or mode-locking based on an ion-doped gain fiber. Due to the limitation of the gain bandwidth, the two wavelengths generated by this method are usually very close, thus limiting its application.

2. Realize dual-wavelength synchronous Q-switching or mode-locking based on two kinds of gain fibers with different doped ions. These two kinds of gain fibers are respectively in two different cavities, and the two cavities respectively realize dual-wavelength synchronous Q-switching or mode-locking by sharing a Q modulator or a broadband saturable absorber. The two wavelengths generated by this method are relatively far apart, but its structure is relatively complex, and it requires higher fabrication of Q modulators or saturable absorbers.

3. A cascaded dual-wavelength synchronous pulsed laser based on an ion-doped gain fiber. Cascading is to generate another wavelength of laser light by transitioning from the lower energy level of the laser to a lower energy level. This method uses Q-switching or mode-locking technology to realize the transition between two energy levels of the ion to generate pulsed laser light. During this process, the number of upper-level inversion particles of the other two energy levels of the ion is periodically modulated. , resulting in a dual-wavelength synchronous pulsed laser. However, this is related to factors such as ion doping concentration, doped matrix, and cavity parameters. At present, the cascading of holmium-doped or erbium-doped fluoride fibers is mainly used to generate dual-wavelength lasers. However, it is difficult to fuse fluoride fibers with silica fibers, which limits the full-fiberization of lasers, and this method currently only achieves wider pulse widths. Dual-wavelength synchronous Q-gain switch pulse output.

Utility model content

The technical problem to be solved by the utility model is to provide a dual-wavelength synchronous pulsed fiber laser based on a rare earth ion co-doped fiber, aiming to realize full-fiber double-wavelength synchronization by using a rare earth ion co-doped fiber with energy transfer between ions Pulsed Fiber Lasers.

The utility model provides a dual-wavelength synchronous pulse fiber laser based on a rare earth ion co-doped optical fiber. The LD pump source is connected to the resonant cavity, and the rare earth ion co-doped optical fiber is located in the resonant cavity for absorbing the pump light emitted by the continuous light LD pump source and radiating to generate laser light. The resonant cavity is a linear Cavity structure or ring cavity structure.

Further, the linear cavity structure includes devices: broadband reflector, saturable absorber, pump coupling device, rare earth ion co-doped optical fiber, optical fiber wavelength division multiplexer WDM ₁ , optical delay line DL ₁ , fiber Bragg grating FBG ₁ and Fiber Bragg Grating FBG ₂ ;

The linear cavity structure includes a first linear cavity and a second linear cavity, wherein the first linear cavity includes sequentially connected broadband mirrors, saturable absorbers, pump coupling devices, rare earth ion co-doped optical fibers, Optical fiber wavelength division multiplexer WDM ₁ and fiber Bragg grating FBG ₁ , the second linear cavity includes sequentially connected broadband mirrors, saturable absorbers, pump coupling devices, rare earth ion co-doped optical fibers, optical fiber wavelength division multiplexing WDM ₁ , optical delay line DL ₁ and fiber Bragg grating FBG ₂ ; the continuous optical LD pump source is connected to the linear cavity structure through the pump coupling device;

The first linear cavity constitutes a sensitized ion radiation laser guiding resonant cavity, and the second linear cavity constitutes a sensitized ion radiation laser guided resonant cavity; the first linear cavity and the second linear cavity The cavities are connected through the optical fiber wavelength division multiplexer WDM ₁ .

Further, the broadband reflector is one of a dielectric mirror, a metal mirror or a fiber optic reflector.

Further, the reflection central wavelength of the fiber Bragg grating FBG ₁ corresponds to the wavelength of the sensitized ion radiation laser, and the transmittance to this wavelength is 5% to 20%; the reflection central wavelength of the fiber Bragg grating FBG ₂ corresponds to the wavelength of the sensitized ion radiation laser The ions are sensitized to the wavelength of the laser light and have a transmittance of 5% to 20% for the wavelength.

Further, the ring cavity structure includes devices: optical fiber wavelength division multiplexer WDM ₁ , pump coupling device, rare earth ion co-doped optical fiber, optical fiber wavelength division multiplexer WDM ₂ , optical fiber coupler OC ₁ , fiber polarization independent Isolator ISO ₁ and saturable absorber or equivalent saturable absorber, fiber coupler OC ₂ , fiber polarization independent isolator ISO ₂ and optical delay line DL ₁ ;

The ring cavity structure includes a first ring cavity and a second ring cavity, wherein the first ring cavity includes a fiber wavelength division multiplexer WDM ₁ , a pump coupling device, a rare earth ion co-doped fiber, a fiber wave division multiplexer WDM ₂ , optical fiber coupler OC ₁ , optical fiber polarization-independent isolator ISO ₁ and a saturable absorber or an equivalent saturable absorber, the second annular cavity includes a fiber optic wavelength division multiplexer WDM connected in sequence _1. Pump coupling device, rare earth ion co-doped optical fiber, optical fiber wavelength division multiplexer WDM ₂ , optical fiber coupler OC ₂ , optical fiber polarization-independent isolator ISO ₂ and optical delay line DL ₁ , the continuous optical LD pumping source connected to the annular cavity structure through the pump coupling device;

The first ring cavity constitutes a sensitized ion radiation laser guiding resonator, and the second ring cavity constitutes a sensitized ion radiation laser guided resonator; the first ring cavity and the second ring cavity pass through The optical fiber wavelength division multiplexer WDM ₁ and the optical fiber wavelength division multiplexer WDM ₂ are connected.

Further, the equivalent saturable absorber is a nonlinear polarization rotation structure composed of a fiber polarization controller PC ₁ , a fiber polarizer and a fiber polarization controller PC ₂ connected in sequence.

Further, when the rare earth ion co-doped fiber is single-clad, the pump coupling device is a three-wavelength optical fiber wavelength division multiplexer, and its signal fiber can simultaneously transmit the sensitized ion and the laser irradiated by the sensitized ion , the continuous optical LD pump source is a single-mode pigtail output;

When the rare earth ion co-doped fiber is double-clad, the pump coupling device is a fiber combiner, and the continuous light LD pump source is a multimode pigtail output.

Further, the resonant cavity of the dual-wavelength synchronous pulsed fiber laser further includes an optical delay line DL ₂ , a fiber wavelength division multiplexer WDM and an output terminal connected in sequence.

Further, the rare earth ion co-doped fiber is a single-clad erbium-ytterbium co-doped fiber or a double-clad erbium-ytterbium co-doped fiber.

Compared with the prior art, the utility model has the beneficial effect that: the utility model provides a dual-wavelength synchronous pulse fiber laser based on rare earth ion co-doped optical fiber. On the one hand, a new pulse generation mechanism is used to use a rare earth ion Co-doped fiber as a gain fiber realizes dual-wavelength synchronous pulse output with long wavelengths, simplifies the structure of dual-wavelength synchronous pulse fiber lasers, and avoids the shortcoming of traditional saturable absorbers with narrow operating wavelength range; on the other hand, The device has a high degree of integration and can realize an all-fiber structure, which is beneficial to practical applications; on the other hand, it can output dual-wavelength synchronous pulse lasers with narrower pulse width, higher peak power, and better pulse overlap, and the application efficiency will be greatly improved. improve.

Description of drawings

Fig. 1 is a schematic structural view of a linear cavity dual-wavelength synchronous pulse fiber laser based on a rare earth ion co-doped fiber provided by the first embodiment of the utility model;

Fig. 2 is a schematic structural diagram of a ring-cavity dual-wavelength synchronous pulse fiber laser based on a rare earth ion co-doped fiber provided by the second embodiment of the utility model;

Fig. 3 is a schematic diagram of the process of generating laser light in the Erbium-Ytterbium co-doped optical fiber in the first and second embodiments of the present invention.

detailed description

In order to make the purpose, technical solution and advantages of the utility model clearer, the utility model will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the utility model, and are not intended to limit the utility model.

The main realization idea of the utility model is: after the pump light is absorbed by the sensitizing ions in the rare earth ion co-doped optical fiber and transitions from the ground state to the excited state, there are some interactions between the sensitizing ions in the excited state and the sensitized ions, through energy transfer The sensitized ions are pumped from the ground state to the excited state, and the sensitized ions in the excited state return to the ground state through energy level transitions and radiate to generate a laser with a wavelength; at the same time, some sensitized ions in the excited state pass through energy level transitions Return to the ground state and radiate to produce another wavelength of laser light. Two resonant cavities are constructed based on the above principles, one of which is used to transmit the laser of sensitized ion radiation, and the other is used to transmit the laser of sensitized ion radiation, and each resonant cavity can be a linear cavity or a ring cavity (this practical Novel embodiment provides two are linear cavities or both are ring cavities), the cavity length of these two resonant cavities is approximately equal, can pass in the laser cavity that is irradiated by sensitized ions (or sensitized ions) The insertion of the optical delay line DL ₁ is used to precisely adjust the cavity lengths of the two cavities to be strictly equal (in the embodiments of the present invention, the optical delay line DL ₁ is inserted in the laser cavity irradiated by sensitized ions). By inserting a saturable absorber or an equivalent saturable absorber with appropriate parameters in the laser cavity of the sensitized ion radiation, Q-switching or mode-locking the laser sensitized ion radiation to generate pulsed laser light, this process is periodic The gain of the sensitized ion radiation laser is modulated and a synchronous pulse laser is generated, thereby realizing a dual-wavelength synchronous pulse fiber laser. Regardless of whether the output of the two resonators is a synchronous Q-switching-gain switching pulse or a synchronous mode-locking pulse, due to energy transfer, the energy level life of the two lasers is different, and there is a certain delay in the time of the two synchronous pulse sequences, through the optical The delay line DL ₂ precisely controls the optical path difference of the two beams, so that the two sync pulses can be better overlapped together and output together from the output terminal through a WDM.

The following specific examples are given to introduce this dual-wavelength synchronous pulsed fiber laser:

Embodiment 1 introduces a linear cavity dual-wavelength synchronous pulsed fiber laser based on a rare earth ion co-doped fiber, as shown in Figure 1:

Including broadband reflector 101, saturable absorber 102, CW LD pump source 103 with pigtail output, pump coupling device 104, rare earth ion co-doped fiber 105, fiber wavelength division multiplexer WDM ₁ 106, optical delay line DL ₁ 107, fiber Bragg grating FBG ₁ 108, fiber Bragg grating FBG ₂ 109, and also includes an optical delay line DL ₂ 110, a fiber wavelength division multiplexer WDM ₂ 111 and an output port.

Among them, the devices 101-109 constitute the linear cavity dual-wavelength synchronous pulse fiber laser 10, and the devices 110-111 are used to better overlap the two synchronous pulses and output them simultaneously.

Specifically, the broadband mirror 101, the fiber Bragg grating FBG ₁ 108 and the devices between them constitute a sensitized ion radiation laser guiding resonator, and the broadband mirror 101, the fiber Bragg grating FBG ₂ 109 and the devices in between The device constitutes the guided resonant cavity of the sensitized ion radiation laser; the guided resonant cavity of the sensitized ion radiation laser and the guided resonant cavity of the sensitized ion radiation laser pass through the optical fiber wavelength division multiplexer WDM ₁ 106 are connected.

Specifically, the rare earth ion co-doped optical fiber 105 is a single-clad erbium-ytterbium co-doped optical fiber, wherein the sensitized ions are ytterbium ions irradiated to generate 1 μm laser light, and the sensitized ions are erbium ions irradiated to generate 1.5 μm laser light. The continuous optical LD pump source 103 is a 975nm LD output by a single-mode pigtail, and the pump coupling device 104 is a three-wavelength wavelength division multiplexer of 975/1064&1550nm, and its signal fiber can simultaneously transmit 1064nm and 1550nm lasers, The pump light is coupled into the erbium-ytterbium co-doped fiber. The broadband reflector 101 is a broadband reflective gold film with high reflection to the laser in the two bands of 1 μm and 1.5 μm, and the saturable absorber 102 is a carbon nanotube film that is only Q-switched or mode-locked for the 1 μm laser, and the carbon nanotube film and broadband The reflective gold film is sequentially coated on the end face of the signal fiber of the 975/1064&1550nm wavelength division multiplexer. Optical fiber wavelength division multiplexer WDM ₁ 106 and optical fiber wavelength division multiplexer WDM ₂ 111 are 1064/1550nm WDM, optical delay line DL ₁ 107 and optical delay line DL ₂ 110 work in the 1.5μm band, fiber Bragg grating FBG ₁ 108 and fiber Bragg grating FBG ₂ 109 have reflection center wavelengths corresponding to 1 μm and 1.5 μm, respectively, and are partially transmissive to laser light of 1 μm and 1.5 μm (transmittance ranges from 5% to 20%, can be 10%). The broadband reflective gold film, the fiber Bragg grating FBG ₁ 108 and the devices in between form a 1 μm laser guiding resonant cavity, and the generated 1 μm pulse laser is output through the fiber Bragg grating FBG ₁ 108 . The broadband reflective gold film, the fiber Bragg grating FBG ₂ 109 and the devices in between form a resonant cavity where the 1.5 μm laser is guided, and the generated 1.5 μm pulsed laser is output through the fiber Bragg grating FBG ₂ 109 .

Q-switching for 1μm laser:

The saturable absorber 102 only has an effect on the laser sensitized ion radiation, the saturable absorber 102 performs Q-switching on the laser sensitized ion radiation, performs gain modulation on the laser irradiated by sensitized ions, and generates sensitized ions 1 μm modulated The Q pulse laser is output from the fiber Bragg grating FBG ₁ 108 to generate synchronous sensitized ion 1.5 μm gain switch pulse laser and output from the fiber Bragg grating FBG ₂ 109 . There is a certain delay in the time of the two synchronous pulse lasers radiated by sensitizing ions and sensitized ions. The optical path difference between the two beams of light is precisely controlled through the optical delay line DL ₂ 110, so that the two synchronous pulses can be better overlapped. together and output simultaneously from the output.

For 1μm laser mode locking:

The saturable absorber 102 performs mode-locking on the laser irradiated by the sensitized ion, and performs gain modulation on the laser irradiated by the sensitized ion, thereby generating 1 μm mode-locked pulsed laser light of the sensitized ion and outputting it from the fiber Bragg grating FBG ₁ 108, Through the precise adjustment of the optical delay line DL ₁ 107, the cavity lengths of the two laser resonators of 1 μm and 1.5 μm are equal. At this time, the synchronous 1.5 μm pumped mode-locked pulse laser of sensitized ions is generated and transmitted from the fiber Bragg grating FBG ₂ 109 output. There is a certain delay in the time of the two synchronous pulse lasers radiated by sensitizing ions and sensitized ions. The optical path difference between the two beams of light is precisely controlled through the optical delay line DL ₂ 110, so that the two synchronous pulses can be better overlapped. together and output simultaneously from the output.

Embodiment 2 introduces a ring-cavity dual-wavelength synchronous pulse fiber laser based on a rare earth ion co-doped fiber, as shown in Figure 2:

Including optical fiber wavelength division multiplexer WDM ₁ 200, continuous optical LD pump source 201 with pigtail output, pump coupling device 202, rare earth ion co-doped optical fiber 203, optical fiber wavelength division multiplexer WDM ₂ 204, optical fiber coupler OC ₁ 205, fiber optic polarization controller PC ₁ 206, fiber optic polarization independent isolator ISO ₁ 207, fiber optic polarizer 208, fiber optic polarization controller PC ₂ 209, fiber optic coupler OC ₂ 210, fiber optic polarization independent isolator ISO ₂ 211 , an optical delay line DL ₁ 212, which also includes an optical delay line DL ₂ 213, an optical fiber wavelength division multiplexer WDM ₃ 214 and an output port.

Among them, the devices 200-209 constitute the sensitized ion radiation laser guiding resonant cavity 20, and the devices 200-204, 210-212 constitute the sensitized ion radiation laser guided resonant cavity 21; the two ring cavities are multiplexed by optical fiber WDM ₁ 200 and fiber wavelength division multiplexer WDM ₂ 204 are connected to form a ring cavity dual-wavelength synchronous pulse fiber laser 2. Devices 213-214 are used to better overlap two synchronous pulses and output them simultaneously.

Specifically, the rare earth ion co-doped fiber 203 is a double-clad erbium-ytterbium co-doped fiber, in which the sensitized ions are ytterbium ions irradiated to generate 1 μm laser light, and the sensitized ions are erbium ions irradiated to generate 1.5 μm laser light. The CW LD pump source 201 is a 975nm LD output from a multimode pigtail, and the pump coupling device 202 is a (2+1)x1 fiber combiner, which couples the pump light into the erbium-ytterbium co-doped fiber. Optical fiber wavelength division multiplexer WDM ₁ 200 and optical fiber wavelength division multiplexer WDM ₂ 204 are 1064/1550nm WDM, which connect two ring cavities; optical fiber coupler OC ₁ 205 and optical fiber coupler OC ₂ 210 respectively work in 1μm and 1.5μm bands, and output lasers in the 1μm and 1.5μm bands respectively; the fiber polarization independent isolator ISO ₁ 207 and the fiber polarization independent isolator ISO ₂ 211 work in the 1μm and 1.5μm bands respectively, which make their rings The cavity conducts in one direction, effectively avoiding the hole-burning effect in space; the device 208 is a fiber polarizer in the 1μm band, and it forms an NPR (Nonlinear polarization rotation, nonlinear polarization rotation) with the fiber polarization controller PC ₁ 206 and the fiber polarization controller PC ₂ 209 Rotation) structure (that is, equivalent saturable absorber), used for Q-switching or mode-locking of 1 μm laser; optical delay line DL ₁ 212 and optical delay line DL ₂ 213 work in the 1.5 μm wavelength band. The 1μm laser guiding resonant cavity is formed by the devices 200-209, and the 1μm pulsed laser generated is output through the fiber coupler OC ₁ 205, and the 1.5μm laser is guided by the components 200-204, 210-212, and the generated 1.5μm pulsed laser is The pulsed laser is output through the fiber coupler OC ₂ 210 .

Q-switching for 1μm laser:

The NPR performs Q-switching on the sensitized ion radiation laser, and performs gain modulation on the sensitized ion-radiated laser to generate a 1 μm Q-switched pulse laser of the sensitized ion and output it from the fiber coupler OC ₁ 205 to generate synchronous sensitized The 1.5μm gain switch pulse laser for sensitizing ions is output from the fiber coupler OC ₂ 210; the two synchronous pulse lasers irradiated by the sensitized ions and the sensitized ions have a certain delay in time, and are precisely passed through the optical delay line DL ₂ 213 The optical path difference of the two beams of light is controlled, so that the two synchronous pulses can be better overlapped and output simultaneously from the output terminal.

For 1μm laser mode locking:

The NPR performs mode-locking on the laser irradiated by sensitized ions, and performs gain modulation on the irradiated laser by sensitized ions, thereby generating 1 μm mode-locked pulsed laser light of sensitized ions and outputting it from the fiber coupler OC ₁ , by precisely adjusting the optical delay The line DL ₁ 212 makes the cavity lengths of the 1 μm and 1.5 μm laser resonators equal. At this time, a synchronous 1.5 μm pumped mode-locked pulse laser of sensitized ions is generated and output from the fiber coupler OC ₂ 210 . There is a certain delay in the time of the two synchronous pulse lasers radiated by the sensitizing ion and the sensitized ion, and the optical path difference between the two beams of light is precisely controlled through the optical delay line DL ₂ 213, so that the two synchronous pulses can be better overlapped together and output simultaneously from the output.

In the embodiment of the present invention, the device 208 is an optical fiber polarizer that can form a nonlinear polarization rotation (NPR) structure with two optical fiber polarization controllers PC ₁ and PC ₂ . In fact, the device 208 can also be a saturable absorber , no matter whether the device 208 is a saturable absorber or a fiber polarizer that can form a nonlinear polarization rotation (NPR) structure with two fiber polarization controllers PC ₁ , PC ₂ , they all act on lasers that sensitize ion radiation.

Below in conjunction with accompanying drawing 3, the operating principle of embodiment 1 and embodiment 2 is described further:

After the 975nm continuous pump light is coupled into the erbium-ytterbium co-doped fiber, the Yb ³⁺ ion as a sensitizer absorbs the pump light and transitions from the ground state ² F _7/2 energy level to the ² F _5/2 energy level, Partially excited Yb ³⁺ ions interact with Er ³⁺ ions, and Er ³⁺ ions are pumped from the ground state ⁴ F _15/2 energy level to ⁴ I _11/2 energy level through energy transfer. In addition, some Yb ³⁺ ions in the excited state form a population inversion distribution between the ² F _5/2 - ² F _7/2 energy levels, and this part of the Yb ³⁺ ions in the excited state passes through ² F _5/2 → ² The F _7/2 energy level transitions back to the ground state ² F _7/2 energy level, radiates in the 1 μm laser-guided resonator cavity and generates 1 μm continuous laser light. At the same time, the Er ³⁺ ions pumped to the ⁴ I _11/2 energy level are relaxed through the non-radiative transition process to the ⁴ I _13/2 energy level, and at the ⁴ I _13/2 - ⁴ F _15/2 energy level The population inversion distribution is formed between them, and then the Er ³⁺ ions in these excited states transition back to the ground state ⁴ F _15/2 energy level through the ⁴ I _13/2 → ⁴ F _15/2 energy level, and are guided by the 1.5 μm laser The resonant cavity radiates and produces a 1.5μm continuous laser.

Q-switching for 1μm laser:

Through the saturable absorption of NPR or carbon nanotube film, the 1 μm continuous laser is passively modulated, so that a 1 μm Q-switched pulsed laser is generated in the guided resonant cavity. Due to energy transfer and non-radiative transition, the process generated by 1μm Q-switched pulsed laser periodically modulates the number of inversion particles from ⁴ I _13/2 → ⁴ F _15/2 , that is, ⁴ I _13/2 → ⁴ F ₁₅ The 1.5μm laser corresponding to the _/2 level transition is periodically gain-modulated. Due to the long time of this process, the number of inversion particles accumulated in the ⁴ I _13/2 energy level is large enough (the gain is large enough), which is enough to generate a gain-switched pulsed laser of 1.5 μm. Since the accumulation of reversed particle numbers in the two processes of ² F _5/2 → ² F _7/2 and ⁴ I _13/2 → ⁴ F _15/2 is synchronous, the generated Q-switching pulse of 1 μm and 1.5 μm The gain switching pulses of the laser are synchronous, which has nothing to do with whether the 1.5μm laser guided resonant cavity has the same length as the 1μm laser guided resonant cavity, but because the lifetime of the ^{2 F} _{5/2 energy} level and the energy ¹ _{μm and 1.5} ^{_ _} _{_} ^_ There is a certain delay in the synchronous Q-gain switching pulse of μm.

For 1μm laser mode locking:

Similarly, through the saturable absorption of NPR or carbon nanotube film, the 1 μm continuous laser is passively modulated, so that a 1 μm mode-locked pulsed laser is generated in the guided resonator. Due to energy transfer and non-radiative transitions, the process of 1 μm mode-locked pulsed laser generation performs periodic gain modulation on the 1.5 μm laser corresponding to the ⁴ I _13/2 → ⁴ F _15/2 energy level transition. However, since the period of the mode-locked pulse is usually much shorter than the period of the Q-switched pulse, the period of this gain modulation is greatly shortened, and it is not enough to produce 1.5 μm when the number of inversion particles accumulated at the ⁴ I _13/2 level is not enough Gain-switched pulsed laser. However, at this time, if the 1.5 μm laser guided resonator is controlled to have the same length as the 1 μm laser guiding resonator, the period of gain modulation is equal to the time for the 1.5 μm photons to go back and forth in the guided resonator, so the guided The initial pulse in the resonant cavity can be amplified only when Er ³⁺ ions are pumped (energy transfer) by excited Yb ³⁺ ions when they reach the gain medium and are in the population inversion state. In this way, a stable 1.5 μm synchronous pump mode-locked pulse is finally obtained. Similarly, since the energy level lifetime of ² F _5/2 is different from that of ⁴ I _13/2 , the inverse particles of ² F _5/2 → ² F _7/2 and ⁴ I _13/2 → ⁴ F _15/2 Due to the different numbers and the time required for energy transfer and non-radiative transition, there is a certain delay in the synchronous mode-locked pulses of 1 μm and 1.5 μm. The synchronous mode-locking pulse has a narrower pulse width and higher peak power than the aforementioned synchronous Q-gain switching pulse.

Furthermore, the rare earth ion co-doped optical fibers in the two embodiments of the present invention are all erbium and ytterbium co-doped optical fibers. In fact, the present invention is also applicable to other rare earth ion co-doped optical fibers such as thulium and ytterbium co-doped fibers. In addition, if the polarization-maintaining rare earth ion co-doped fiber and polarization-maintaining device are used, the system can realize linearly polarized dual-wavelength synchronous laser pulse output.

The utility model realizes a full-fiber double-wavelength synchronous pulse fiber laser by using a rare-earth ion co-doped optical fiber with energy transfer between ions. The device has high integration and can realize a full-fiber structure, which is beneficial to practical application.

The above descriptions are only preferred embodiments of the present utility model, and are not intended to limit the present utility model. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present utility model shall be included in this utility model. within the scope of protection of utility models.

Claims (9)

1. a kind of dual wavelength lock-out pulse optical fiber laser based on rare earth ion co-doped fiber, it is characterised in that the double wave Lock-out pulse optical fiber laser long includes continuous light LD pumping sources, rare earth ion co-doped fiber resonant cavity, the continuous light LD Pumping source connects the resonator, and the rare earth ion co-doped fiber is used to absorb the continuous light LD pumps in being located at the resonator Pump light that Pu source sends simultaneously radiates generation laser, and the resonator is linear cavity configuration or ring cavity structure.

2. dual wavelength lock-out pulse optical fiber laser as claimed in claim 1, it is characterised in that wrapped in the linear cavity configuration Include device：Broadband mirrors, saturable absorber, pump coupling device, rare earth ion co-doped fiber, optical fibre wavelength division multiplexer WDM₁, optical delay line DL₁, optical fiber bragg grating FBG₁And optical fiber bragg grating FBG₂；

The linear cavity configuration includes the first linear cavity and the second linear cavity, wherein, first linear cavity includes being sequentially connected Broadband mirrors, saturable absorber, pump coupling device, rare earth ion co-doped fiber, optical fibre wavelength division multiplexer WDM₁With Optical fiber bragg grating FBG₁, second linear cavity includes the broadband mirrors, saturable absorber, the pumping coupling that are sequentially connected Clutch part, rare earth ion co-doped fiber, optical fibre wavelength division multiplexer WDM₁, optical delay line DL₁And optical fiber bragg grating FBG₂； The continuous light LD pumping sources are connected by the pump coupling device with the linear cavity configuration；

First linear cavity constitutes sensitized ions radiation laser guiding resonator, and second linear cavity is constituted and is sensitized ion Radiation laser is directed to resonator；First linear cavity and second linear cavity pass through the optical fibre wavelength division multiplexer WDM₁ Couple together.

3. dual wavelength lock-out pulse optical fiber laser as claimed in claim 2, it is characterised in that the broadband mirrors are to be situated between One kind in matter mirror, speculum or fiber reflector.

4. dual wavelength lock-out pulse optical fiber laser as claimed in claim 2, it is characterised in that the Fiber Bragg Grating FBG FBG₁Reflection kernel wavelength correspond to the wavelength of sensitized ions radiation laser, and be 5% to 20% to the transmissivity of the wavelength； Optical fiber bragg grating FBG₂Reflection kernel wavelength correspond to and be sensitized the wavelength of ionizing radiation laser, and to the saturating of the wavelength It is 5% to 20% to penetrate rate.

5. dual wavelength lock-out pulse optical fiber laser as claimed in claim 1, it is characterised in that wrapped in the ring cavity structure Include device：Optical fibre wavelength division multiplexer WDM₁, pump coupling device, rare earth ion co-doped fiber, optical fibre wavelength division multiplexer WDM₂, light Fine coupler OC₁, the unrelated isolator ISO of optical fiber polarisation₁With saturable absorber or equivalent saturable absorber, fiber coupler OC₂, the unrelated isolator ISO of optical fiber polarisation₂With optical delay line DL₁；

The ring cavity structure includes first annular chamber and the second annular chamber, wherein, the first annular chamber includes being sequentially connected Optical fibre wavelength division multiplexer WDM₁, pump coupling device, rare earth ion co-doped fiber, optical fibre wavelength division multiplexer WDM₂, fiber coupling Device OC₁, the unrelated isolator ISO of optical fiber polarisation₁With saturable absorber or equivalent saturable absorber, the second annular chamber bag Include the optical fibre wavelength division multiplexer WDM being sequentially connected₁, pump coupling device, rare earth ion co-doped fiber, optical fibre wavelength division multiplexer WDM₂, fiber coupler OC₂, the unrelated isolator ISO of optical fiber polarisation₂With optical delay line DL₁, the continuous light LD pumping sources lead to The pump coupling device is crossed to be connected with the ring cavity structure；

The first annular chamber constitutes sensitized ions radiation laser guiding resonator, and second annular chamber is constituted and is sensitized ion Radiation laser is directed to resonator；The first annular chamber and second annular chamber pass through the optical fibre wavelength division multiplexer WDM₁ With optical fibre wavelength division multiplexer WDM₂Couple together.

6. dual wavelength lock-out pulse optical fiber laser as claimed in claim 5, it is characterised in that the equivalent saturable absorption Body is the optical fiber polarization controller PC being sequentially connected₁, optical fiber polarizer and optical fiber polarization controller PC₂What is constituted is non-linear inclined Shake rotational structure.

7. the dual wavelength lock-out pulse optical fiber laser as described in any one of claim 2 or 5, it is characterised in that when described dilute When native ion co-doped fiber is single covering, the pump coupling device is three long wavelength fiber wavelength division multiplexers, and its signal fibre can be same When transmission sensitized ions and be sensitized the laser of ionizing radiation, the continuous light LD pumping sources are single-mode tail fiber output；

When the rare earth ion co-doped fiber is double clad, the pump coupling device is optical-fiber bundling device, the continuous light LD pumping sources are multimode pigtail output.

8. dual wavelength lock-out pulse optical fiber laser as claimed in claim 7, it is characterised in that the dual wavelength lock-out pulse Also include the optical delay line DL being sequentially connected after the resonator of optical fiber laser₂, optical fibre wavelength division multiplexer WDM and output End.

9. dual wavelength lock-out pulse optical fiber laser as claimed in claim 8, it is characterised in that the rare earth ion is co-doped with light Fibre is single covering erbium-ytterbium co-doped fiber or double clad erbium-ytterbium co-doped fiber.