CN116742471A

CN116742471A - Method and apparatus for single wavelength laser generation

Info

Publication number: CN116742471A
Application number: CN202210193612.1A
Authority: CN
Inventors: 刘沛; 张楷; 吴波
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2022-03-01
Filing date: 2022-03-01
Publication date: 2023-09-12
Also published as: WO2023165511A1

Abstract

The embodiment of the application provides a single-wavelength laser generator and a method for generating single-wavelength laser. The laser resonance unit processes at least one beam of multimode pump laser and outputs a first beam and a first laser respectively, wherein the first beam comprises a first radiation beam, a second radiation beam and residual multimode pump laser, the first radiation beam is generated after the at least one beam of multimode pump laser is pumped in the laser resonance unit, and the second radiation beam comprises a beam generated by oscillation of the first laser in the laser resonance unit and a beam generated after the at least one beam of multimode pump laser is pumped in the laser resonance unit. The pump recovery unit blocks the first radiation beam and the second radiation beam included in the first beam and re-inputs the residual multimode pump laser light to the laser resonance unit. The embodiment of the application can improve the utilization efficiency of the pump laser and avoid the influence of self-oscillation on the first laser signal.

Description

Method and apparatus for single wavelength laser generation

Technical Field

Embodiments of the present application relate to the field of optical communications, and more particularly, to a single wavelength laser generator and a method of generating a single wavelength laser in the field of optical communications.

Background

The fiber semiconductor laser can realize the output of high-power and high-brightness laser, wherein the cladding pumping fiber laser of the multimode semiconductor laser has extremely high reliability and extremely low cost. The existing mature cladding pumping technology outputs 1 mu m laser, however, high-power and high-efficiency laser output in 980nm wave band faces serious challenges.

When the ytterbium-doped fiber is pumped by using multimode pump laser around 900nm, the ytterbium-doped fiber can generate stronger gain in 980nm wave band, but meanwhile, some problems exist: (1) The 980nm wave band also has a very high absorption section, when the length of the ytterbium-doped optical fiber exceeds a critical value, the 980nm wave band laser signal can be rapidly absorbed by the ytterbium-doped optical fiber, so that the efficiency is drastically reduced; (2) The radiation of ytterbium ions in the ytterbium-doped fiber in 980nm wave band belongs to a typical three-level system, and the stimulated radiation can be generated by realizing the population inversion only when the upper-level population exceeds 50% of the total population, so that very strong pumping power is also required for generating 980nm wave band laser.

Since the 980nm band laser needs to meet both a shorter fiber length and a higher pump power, this results in a very high residual pump power, limiting the output power and conversion efficiency of the 980nm band laser.

The use efficiency of the pump can be improved by adopting cladding light recycling. However, the laser forms multiple ring light paths due to the connection of the optical fibers at both ends. Even in the cladding, the amplified spontaneous emission (amplified spontaneous emission, ASE) with the wavelength of 1 μm can cause self-oscillation, so that the upper level particle number in the ytterbium-doped optical fiber is rapidly consumed, and the laser with the wavelength of 980nm can be absorbed more strongly, so that the conversion efficiency of 980nm is not increased and reduced. Therefore, a solution against 1 μm band interference is needed.

Disclosure of Invention

The application provides a single-wavelength laser generator and a method for generating single-wavelength laser, which can avoid the interference of a 1 mu m wave band and improve the output power and conversion efficiency of 980nm wave band laser.

In a first aspect, there is provided a single wavelength laser generator comprising: the laser resonance unit and the pump recovery unit. The laser resonance unit includes a first input port for inputting at least one multimode pump laser beam, a first output port for processing the at least one multimode pump laser beam to output a first beam from the first output port and a first laser beam from the second output port, the first beam including a first radiation beam generated after the at least one multimode pump laser beam is pumped in the laser resonance unit, a second radiation beam including a beam generated after the first laser beam is oscillated in the laser resonance unit, and a residual multimode pump laser beam, the second radiation beam including a beam generated after the at least one multimode pump laser beam is pumped in the laser resonance unit, the first radiation beam being different from the second radiation beam in a wavelength range of the first radiation beam, the first laser beam being generated by oscillation of the first radiation beam in the laser resonance unit. The pump recovery unit comprises a second input port, a third output port and a blocking subunit, wherein the second input port is used for inputting the first beam, the blocking subunit is used for blocking the first radiation beam and the second radiation beam which are included by the first beam, the third output port is used for outputting residual multimode pump laser, the residual multimode pump laser is input into the first input port of the laser resonance unit, and the second input port of the pump recovery unit is optically connected with the first output port of the laser resonance unit.

According to the single-wavelength laser generator provided by the application, the residual pump laser is recovered, and the first radiation beam and the second radiation beam are blocked, so that the utilization efficiency of multimode pump laser is improved, the influence of self-oscillation on a first laser signal is avoided, the stable operation of a system is ensured, and the integral conversion efficiency is improved.

With reference to the first aspect, in an implementation manner of the first aspect, the at least one multimode pump laser includes: the residual multimode pump laser light and externally input multimode pump laser light.

It will be appreciated that the residual multimode pump laser may be multimode pump laser input into the laser resonator unit but underutilized, and that the externally input multimode pump laser may be provided by a multimode pump connected to a single wavelength laser generator provided by the present application.

According to the single-wavelength laser generator provided by the application, the service efficiency of the pump laser is improved by recycling the residual pump laser.

With reference to the first aspect, in an implementation manner of the first aspect, a wavelength range of the multimode pump laser is 900nm to 970nm, a wavelength range of the first laser and the first radiation beam is 970nm to 990nm, and a wavelength range of the second radiation beam is 1000nm to 1100nm.

With reference to the first aspect, in an implementation manner of the first aspect, the pump recovery unit includes: the beam splitter is used for inputting the first light beam of the first light path to a second light path, the first light path is a light path comprising double-cladding ytterbium-doped fibers, and the second light path is a light path comprising M multimode recovery fibers with the same specification. The input end of the beam splitter is connected with 1 double-clad optical fiber, and the output end of the beam splitter is connected with 1 double-clad optical fiber and N multimode recovery optical fibers with the same specification, wherein M, N is a positive integer;

specifically, the types of ytterbium ions of the double-cladding ytterbium-doped fiber correspond to the wavelength output by the single-wavelength laser generator provided by the application. For example, when the wavelength output by the single-wavelength laser generator is 980nm, the rare earth element ion of the double-clad rare earth element-doped optical fiber may be ytterbium ion.

The correspondence relationship listed above is merely an exemplary illustration, and the present application is not limited thereto, as long as it satisfies that the rare earth element ion can have a power amplifying effect on the light beam of the corresponding wavelength band.

Specifically, when the residual multimode pump laser is re-input into the laser resonance unit in a unidirectional circulation manner, the second optical path includes M multimode recovery fibers with the same specification corresponding to N multimode recovery fibers with the same specification at the output end of the beam splitter, that is, M is equal to N;

When the residual multimode pump laser is re-input into the laser resonance unit in a bidirectional circulation mode, the second optical path includes half of the M multimode recovery fibers with the same specification, i.e., half of the M multimode recovery fibers with the same specification, at the output end of the beam splitter.

With reference to the first aspect, in an implementation manner of the first aspect, the blocking subunit of the pump recovery unit is further configured to block the first radiation beam and the second radiation beam of the first optical path and/or the second optical path.

Specifically, the blocking subunit may be disposed only on the first optical path, may be disposed only on the second optical path, or may be disposed on the first optical path and the second optical path, which is not limited in the present application, and may be disposed according to actual requirements of the system.

Optionally, the blocking subunit comprises a narrow band filter or a dichroic mirror or a tilted bragg fiber grating for simultaneously blocking the first radiation beam and the second radiation beam in the fiber core and the fiber cladding of the first optical path and/or the second optical path.

Specifically, the input end and the output end of the blocking subunit can be respectively connected with a double-clad optical fiber, a coreless optical fiber, a multimode recovery optical fiber or a multimode optical fiber array, and the specifications of the optical fibers connected with the input end of the blocking subunit and the output end of the blocking subunit are the same.

For example, if the blocking subunit is disposed on the first optical path, the input end and the output end of the blocking subunit may be connected to the double-clad optical fiber or the coreless optical fiber, respectively; if the blocking subunit is disposed on the second optical path, the input end and the output end of the blocking subunit may be connected to the multimode recovery optical fiber or the multimode optical fiber array, respectively.

With reference to the first aspect, in an implementation manner of the first aspect, the single wavelength laser generator further includes: and the beam combiner is used for combining the at least one beam of multimode pump laser and inputting the at least one beam of multimode pump laser into the laser resonance unit.

The input end of the beam combiner is connected with 1 multimode pumping fiber and N multimode recovery fibers with the same specification, and the output end of the beam combiner is connected with 1 double-clad fiber or coreless fiber, wherein N is a positive integer;

specifically, when the residual multimode pump laser is re-input into the laser resonance unit in a unidirectional circulation manner, the second optical path includes M multimode recovery fibers with the same specification corresponding to N multimode recovery fibers with the same specification at the input end of the beam combiner, that is, M is equal to N;

When the residual multimode pump laser is re-input into the laser resonance unit in a bidirectional circulation mode, the second optical path includes half of the M multimode recovery fibers with the same specification, i.e., half of the N multimode recovery fibers with the same specification, at the input end of the beam splitter.

It will be appreciated that the residual multimode pump laser is derived from the blocking subunit blocking the first and second radiation beams of the first beam.

It should be understood that N in the N multimode recovery fibers with the same specification adopted by the output end of the beam splitter and the input end of the beam combiner are the same positive integer, and just correspond to each other one by one.

With reference to the first aspect, in an implementation manner of the first aspect, the laser resonance unit includes: at least one pair of fiber gratings comprising a high reflection grating fiber and a low reflection grating.

The reflectivity of the high reflection fiber grating to the first laser is larger than a first threshold value, and the reflectivity to the first radiation beam and the second radiation beam is smaller than a second threshold value;

the reflectivity of the low reflection fiber grating to the first laser is smaller than a third threshold value, and the reflectivity to the first radiation beam and the second radiation beam is smaller than a fourth threshold value. The present application is not limited to the values of the first threshold value, the second threshold value, the third threshold value, and the fourth threshold value, and the values may be set by themselves according to the requirements for the output power of the first laser beam, and the like.

The first laser, the first radiation beam and the second radiation beam generated in the laser resonance unit are subjected to different reflectivities through the pair of high-low reflective fiber gratings, so that the first laser and the first radiation beam capable of oscillating to generate the first laser oscillate in the laser resonance unit, and meanwhile, the second radiation beam and the first radiation beam incapable of generating the first laser are lost as much as possible.

With reference to the first aspect, in an implementation manner of the first aspect, the laser resonance unit further includes: and the long-period fiber grating is used for converting the first radiation beam and the second radiation beam in the fiber core into the fiber cladding, so that the beam splitter is beneficial to extracting the first radiation beam and the second radiation beam.

With reference to the first aspect, in an implementation manner of the first aspect, the laser resonance unit further includes: and the double-cladding ytterbium-doped optical fiber is used for amplifying the first laser.

Wherein, the double-cladding ytterbium-doped fiber comprises any one of the following:

large mode field optical fibers, photonic crystal fibers, photonic bandgap fibers, and multi-core fibers.

With reference to the first aspect, in an implementation manner of the first aspect, the laser output unit includes: an isolator or a beam splitter.

The first laser is repeatedly oscillated and power-amplified in a laser resonance unit composed of the at least one pair of fiber gratings and the double-clad rare-earth element doped fiber.

In a second aspect, there is provided a method of generating a single wavelength laser, the method comprising: processing at least one multimode pump laser to obtain a first beam and a first laser, wherein the first beam comprises a first radiation beam, a second radiation beam and residual multimode pump laser, the first radiation beam is generated by pumping the at least one multimode pump laser in a laser resonance unit, the second radiation beam comprises a beam generated by oscillating the first laser in the laser resonance unit, and the second radiation beam comprises a beam generated by pumping the at least one multimode pump laser in the laser resonance unit, the first radiation beam and the second radiation beam are different in wavelength range, and the first laser is generated by oscillating the first radiation beam in the laser resonance unit. The first and second radiation beams comprised by the first beam are blocked and the residual multimode pump laser light is input to the laser resonator unit. Outputting the first laser.

According to the method for generating the single-wavelength laser, provided by the application, the residual pump laser is recovered, and the first radiation beam and the second radiation beam are blocked, so that the utilization efficiency of the multimode pump laser is improved, the influence of self-oscillation on a first laser signal is avoided, and the integral conversion efficiency is improved while the stable operation of the system is ensured.

It will be appreciated that the residual multimode pump laser may be multimode pump laser light that is input into the laser resonator unit but is underutilized, and that the externally input multimode pump laser light may be provided by an external multimode pump.

According to the method for single-wavelength laser provided by the application, the service efficiency of the pump laser is improved by recycling the residual pump laser.

With reference to the first aspect, in an implementation manner of the first aspect, the method further includes: inputting the first light beam in a first light path to a second light path, wherein the first light path is a light path comprising double-cladding ytterbium-doped optical fibers, and the second light path is a light path comprising M multimode recovery optical fibers with the same specification.

Specifically, the types of ytterbium ions of the double-cladding ytterbium-doped fiber correspond to the wavelength of the single-wavelength laser provided by the application. For example, when the wavelength of the single-wavelength laser light outputted is 980nm, the rare earth element ion of the double-clad rare earth element-doped optical fiber may be ytterbium ion.

With reference to the first aspect, in an implementation manner of the first aspect, blocking the first radiation beam and the second radiation beam included in the first beam includes: the first radiation beam and the second radiation beam of the first optical path and/or the second optical path are blocked.

Specifically, the first optical path, the second optical path, the first radiation beam of the first optical path, and the second radiation beam of the second optical path may be blocked, which is not limited in the present application, and may be set according to actual requirements of the system.

With reference to the first aspect, in an implementation manner of the first aspect, blocking the first radiation beam and the second radiation beam included in the first beam further includes: the first radiation beam and the second radiation beam of the first optical path and/or the second optical path in the fiber core and the fiber cladding are blocked simultaneously.

With reference to the first aspect, in an implementation manner of the first aspect, the method further includes: and combining the at least one beam of multimode pump light and inputting the at least one beam of multimode pump light into the laser resonance unit.

It will be appreciated that the residual multimode pump laser is a multimode pump light resulting from blocking the first and second radiation beams of the first beam.

With reference to the first aspect, in an implementation manner of the first aspect, the first laser is generated by oscillating the first radiation beam in a laser resonance unit, including:

With reference to the first aspect, in an implementation manner of the first aspect, the method further includes: the first radiation beam and the second radiation beam in the fiber core are converted into the fiber cladding, thereby facilitating extraction of the first radiation beam and the second radiation beam.

With reference to the first aspect, in an implementation manner of the first aspect, the laser resonance unit further includes: and the double-cladding ytterbium-doped optical fiber is used for amplifying the first wavelength laser.

In a third aspect, an optical transmitting device is provided, including the single wavelength laser generator of the first aspect and its possible implementation manner, an adjustable optical splitter, and an optical amplifier, where the adjustable optical splitter is configured to split a single wavelength laser generated by the single wavelength laser generator into multiple optical waves, and inject the multiple optical waves as pump lasers into the optical amplifier respectively, and the optical amplifier uses the pump lasers to pump and amplify optical waves in a specific wavelength band.

Drawings

Fig. 1 shows a schematic block diagram of a single wavelength laser generator 100 of the present application.

Fig. 2 shows a schematic structural diagram of a double-clad rare-earth element doped optical fiber.

Fig. 3 (a) shows a schematic structural diagram of an example of the single-wavelength laser generator 100 of the present application.

Fig. 3 (b) shows another exemplary configuration of the single wavelength laser generator 100 of the present application.

Fig. 3 (c) shows a schematic structural diagram of an example of the blocking subunit of the present application.

Fig. 4 (a) shows another exemplary configuration of the single wavelength laser generator 100 of the present application.

Fig. 4 (b) shows another exemplary configuration of the single wavelength laser generator 100 of the present application.

Fig. 4 (c) shows another exemplary block diagram of the blocking subunit of the present application.

Fig. 5 (a) shows another exemplary configuration of the single wavelength laser generator 100 of the present application.

Fig. 5 (b) shows another exemplary configuration of the single wavelength laser generator 100 of the present application.

Fig. 5 (c) shows another exemplary block diagram of the blocking subunit of the present application.

Fig. 5 (d) shows a schematic structural view of an example of a two-terminal optical fiber arrangement array of the blocking subunit of the present application.

Fig. 6 shows another exemplary structure of the single wavelength laser generator 100 of the present application.

Fig. 7 is a schematic flowchart showing an example of a method of generating a single wavelength laser light according to the present application.

Fig. 8 shows a schematic structural view of the light emitting device of the present application.

Detailed Description

The technical scheme of the application will be described below with reference to the accompanying drawings.

For ease of understanding, prior to describing embodiments of the present application, terms or concepts that may be related to embodiments of the present application are first described. It should be understood that the basic concepts described below are described in the present related art as examples, and the present application is not limited to specific names.

1. Pumping laser: a process that uses a laser to raise (or "pump") electrons from a lower energy level to a higher energy level in an atom or molecule. When the metastable (meta-stable state) or higher level of the population exceeds the ground state or lower level of the population, population inversion may occur to generate stimulated radiation. The pump power of the pump laser must be higher than the laser threshold of the laser and accordingly the wavelength of the pump laser is smaller than the wavelength of the laser to be amplified.

2. Laser: the electrons in the atoms absorb energy and then transition from a low energy level to a high energy level, and when the electrons fall back from the high energy level to the low energy level, the released energy is emitted in the form of photons, so that a laser light source is formed. The external excitation source (i.e. the pumping laser) can pump the particles with the lower energy level to the upper energy level, so that the population inversion is realized between the upper energy level and the lower energy level of the laser, and more particles radiate new photons as a laser light source.

3. Gain medium: the laser gain medium is a medium capable of amplifying laser power, which is a working substance of laser light, that is, a supply of laser light after generating stimulated radiation. The energy level structure of the active particles in the gain medium is well suited to amplify photons of a certain wavelength band according to the principle of stimulated amplification (or stimulated radiation or stimulated scattering principle), and stimulated radiation occurs.

4. Single mode semiconductor laser: when there is only one pump module inside the laser, it is called a single mode laser. The single mode fiber core is relatively thin, and emits a typical gaussian beam, with very concentrated energy, resembling a steep peak.

5. Multimode semiconductor laser: the multiple pump modules are combined together, and multiple pump lasers enter the active optical fiber through the beam combiner, so that a higher-power beam can be obtained, and the laser combined by the multiple modules is a multimode laser. Multimode is equivalent to the combination of a plurality of Gaussian beams, so that the energy distribution is similar to that of a cup with a reverse buckle and is relatively uniform.

Ase: the process in which the spontaneous emission is amplified. Although ASE in a fiber laser is not so strong that it can extract much energy from it, it produces much noise on the laser light to be amplified. In some fiber lasers, laser light cannot be generated at a particular frequency if the gain at other wavelengths is sufficient to generate strong ASE.

Fig. 1 shows a schematic block diagram of a single wavelength laser generator 100 of the present application. As shown in fig. 1, the single wavelength laser generator 100 includes: a laser resonance unit 110, a pump recovery unit 120, and a laser output unit 130. Wherein at least one multimode pump laser light is inputted to the laser resonator unit 110 and ASE of various wavelengths is generated. The laser resonance unit 110 selects ASE (hereinafter, for ease of understanding and distinction, referred to as a first radiation beam) in a wavelength range to be amplified, and forms laser light (hereinafter, for ease of understanding and distinction, referred to as a first laser light) in the wavelength range to be amplified, and limits the first laser light to repeatedly oscillate in a first optical path for power amplification; the pump recovery unit 120 can recover not only the residual multimode pump laser light outputted from the laser resonance unit 110 but also the optical wave of the interference band in the optical fiber.

Specifically, the optical wave of the interference band may be an optical wave of a 1 μm band (hereinafter, for ease of understanding and distinction, denoted as second radiation beam).

It will be appreciated that the optical waves in the optical fiber in the interference band that the pump recovery unit 120 is required to block include the first radiation beam and the second radiation beam.

It should be appreciated that the at least one multimode pump laser pump generates a first radiation beam that oscillates into a first laser light by being limited by the cavity structure of the laser resonator unit 110, and the laser output unit 130 outputs the first laser light with amplified power.

If part of the first radiation beam passes through the limitation of the structure of the laser resonator 110 and does not oscillate to become the first laser, it is also necessary to block it by the pump recovery unit 120.

It will be appreciated that the second radiation beam is generated by the first laser oscillation and the multimode pump laser pumping.

The first and second embodiments of the present application are shown for convenience only, and are not intended to limit the scope of the embodiments of the present application. It is to be understood that the objects so described may be interchanged under appropriate circumstances so as to be able to describe aspects other than the embodiments of the application.

Alternatively, the blocking of the optical wave of the interference band in the optical fiber by the pump recovery unit 120 may occur before the injection of the multimode pump laser light into the laser resonance unit 110 or after the injection of the multimode pump laser light into the laser resonance unit 110.

Illustratively, the first laser and the first radiation beam may have a wavelength range of 970nm to 990nm, the second radiation beam may have a wavelength range of 1000nm to 1100nm, and the multimode pump laser may have a wavelength range of 900nm to 970nm. The application does not limit specific numerical values of the wavelength range, and can correspondingly adjust according to the actual output laser.

Wherein the laser resonator unit 110 includes a double-clad rare earth element doped fiber and at least one pair of fiber gratings.

Specifically, rare earth elements (or rare earth elements) have a large energy difference between a metastable state and a ground state. For example, the energy difference of erbium ions in the metastable and ground states corresponds to the energy of 1550nm photons. Therefore, the stimulated amplification principle (or stimulated radiation or stimulated scattering principle) of the light can be utilized to amplify photons in the 1550nm wave band, namely, the output power of the 1550nm wave band laser is improved; for another example, the energy difference of ytterbium ions in the metastable state and ground state corresponds to the energy of 980nm photons. Thus, the photons in the 980nm band can be amplified by using the principle of stimulated amplification of light (or the principle of stimulated radiation or stimulated scattering), i.e., the output power of the 980nm band laser light can be increased.

As described above, the energy difference between the metastable state and the ground state is different for different rare earth element ions. Accordingly, the corresponding rare earth ion may be selected based on the wavelength of light to be amplified, for example, erbium ion may be used as a dopant ion in a double-clad fiber when light having a wavelength of 1550nm is to be amplified. As another example, when it is desired to amplify light having a wavelength of 1400nm, thulium ions may be used as dopant ions in a double-clad fiber. For another example, praseodymium ions may be used as dopant ions in a double-clad fiber when it is desired to amplify light having a wavelength of 1300 nm. For another example, ytterbium ions may be used as dopant ions in a double-clad fiber when it is desired to amplify light having a wavelength of 980nm, or when the first wavelength is 980 nm.

It should be understood that the method and apparatus for generating a single wavelength laser provided in the embodiments of the present application are not limited to only generating light waves in a first wavelength range, but may also be used to generate light waves in other specific wavelength ranges, and the single wavelength laser generator and the method for generating a single wavelength laser of the present application are merely examples, and the scope of protection of the present application is not limited in any way.

The present application is described by taking 980nm as an example of the first laser wavelength, and the specific value is not limited, and the first laser wavelength range may be used.

The structure and function of the double-clad rare-earth element doped fiber will be described in detail with reference to fig. 2.

In the present application, in order to obtain a laser output in 980nm band, the double-clad rare-earth element-doped optical fiber may be a double-clad ytterbium-doped optical fiber, and the following description will be given by taking the double-clad ytterbium-doped optical fiber as an example. Generally, a dual-clad ytterbium-doped fiber includes: ytterbium-doped fiber core, inner cladding, outer cladding and protective layer.

The ytterbium-doped fiber core may be made of ytterbium-doped silica, and is used as a channel for laser resonance in the laser generator 100, and is also used as an output channel of signal light to be amplified, and is used as an output channel of 980 nm-band signal light in the application. The inner cladding may be composed of pure silica having a much larger lateral dimension and vertical aperture than the ytterbium-doped fiber core and a smaller refractive index than the ytterbium-doped fiber core, which serves as a channel for the multimode pump laser in the single wavelength laser generator 100. The multimode pump laser coupled into the inner cladding is reflected between the inner cladding for multiple times, passes through and is absorbed by the ytterbium-doped fiber core, and stimulated radiation is generated in the ytterbium-doped fiber core; the inner cladding surrounds the ytterbium-doped fiber core, and limits the stimulated radiation process and the generation and transmission of 980 nm-band signal light to the ytterbium-doped fiber core.

For example, a multimode pump laser whose energy is absorbed by ytterbium ions to transition the ytterbium ions to a higher energy level may be irradiated into the laser resonance unit 110, and the energy of photons of 980nm band may be transferred by stimulated radiation between the energy levels, thereby generating laser light of 980nm band.

Fig. 3 (a) shows a schematic structural diagram of an example of the single-wavelength laser generator 100 of the present application. The first optical path is provided with a blocking subunit, and is mainly used for blocking the second radiation beam and the first radiation beam on the first optical path, where the first optical path includes a dual-cladding ytterbium-doped optical fiber, and is also called a main optical path, as shown in fig. 3 (a).

By way of example and not limitation, a combiner is used to combine the externally input multimode pump laser light with cladding light of the second optical path and inject into the laser resonator unit 110. The input end of the beam combiner consists of 1 multimode pumping fiber and N multimode recovery fibers with the same specification, and the output end of the beam combiner consists of 1 double-clad fiber or coreless fiber. Wherein N is a positive integer.

Specifically, the second optical path is a channel of the cladding light when the cladding light is recovered, and is also called a sub-optical path.

In particular, the cladding light comprises residual multimode pump laser, a first radiation beam and ASE of a second wavelength range.

It will be appreciated that the pump recovery unit has blocked the first and second radiation beams before the beam combiner is made, so the pump recovery unit 120 inputs the recovered multimode pump laser light into the beam combiner;

additionally, the multimode pump for providing the externally input multimode pump laser light also inputs the multimode pump laser light into the beam combiner, and thus the beam combiner may combine the multimode pump laser light recovered by the pump recovery unit 120 with the externally input multimode pump laser light and inject the combined multimode pump laser light into the laser resonance unit 110.

The blocking subunit, which is a part of the pump recovery unit 120, has optical fibers at two ends respectively identical to the specifications of the output end of the combiner and the tail fiber of the high-reflection fiber grating, and is mainly used for blocking the first radiation beam and the second radiation beam generated by the double-clad ytterbium-doped fiber in the laser resonance unit 110, so as to pass through the multimode pump laser without loss or with low loss.

In particular, the blocking subunit may comprise a narrow band filter or a dichroic mirror or a tilted bragg fiber grating.

Additionally, the blocking subunit may block the second radiation beam and the first radiation beam in the fiber core and the inner cladding simultaneously.

In this case, the optical fibers at both ends of the blocking subunit may be double-clad optical fibers or coreless optical fibers.

As an example and not by way of limitation, the high reflection fiber grating, the double-clad ytterbium-doped fiber, and the low reflection fiber grating may be used as an example of the laser resonator 110, and the first laser generated by the multimode pump laser pump may be selected and limited to be repeatedly oscillated in the first optical path.

Specifically, the high-reflection fiber grating and the low-reflection fiber grating are inscribed on the fiber core of the double-clad fiber or the coreless fiber matched with the double-clad ytterbium-doped fiber.

The high reflection fiber grating has high reflectivity to the laser in the first wavelength range, and is mainly used for preventing the signal light which is reflected by the low reflection fiber grating and enters the first wavelength range of the laser resonance unit 110 from losing through the high reflection fiber grating again, wherein the high reflectivity is larger than a first threshold value which is more than or equal to 90%; meanwhile, the high reflection fiber grating has low reflectivity to the interference light in the second wavelength range, so that the interference light in the second wavelength range is lost as much as possible, the low reflectivity is smaller than a second threshold value which is less than or equal to 1%.

In addition, the low reflection fiber grating has low reflectivity to the signal light in the first wavelength range, so that the laser output of one part of the first wavelength range can be ensured, and the other part of the first wavelength range laser is reflected into the double-cladding ytterbium-doped fiber to resonate so as to continuously amplify the first wavelength laser, wherein the low reflectivity is smaller than a third threshold value which is less than or equal to 20%; meanwhile, the low reflection fiber grating has low reflectivity for the interference light in the second wavelength range, so that the interference light in the second wavelength range is output from the laser resonance unit 110, and the interference light in the second wavelength range is eliminated, wherein the low reflectivity is smaller than a fourth threshold value which is less than or equal to 1%.

It should be understood that the values of the first threshold, the second threshold, the third threshold, and the fourth threshold are not limited, and may be specifically set according to the power actually required to be amplified by the first light wave.

It should be understood that the first laser light entering the laser resonance unit 110 repeatedly resonates at the high reflection fiber grating and the low reflection fiber grating until the power of the first laser light outputted from the low reflection fiber grating side is balanced with the power of the first laser light continuously amplified between the high reflection fiber grating and the low reflection fiber grating, and the single-wavelength laser generator 100 can smoothly output the first laser light amplified with the power.

It should be appreciated that the first laser light repeatedly passes through the dual-clad ytterbium-doped fiber to generate stimulated radiation during the repeated resonance of the high-reflection fiber grating and the low-reflection fiber grating, and that the second radiation beam is generated when the laser light is amplified in the first wavelength range.

Additionally, the double-clad ytterbium-doped fiber in the laser resonator unit 110 may be any one of a large mode field fiber, a photonic crystal fiber, a photonic band gap fiber, and a multi-core fiber.

Alternatively, the laser resonator unit 110 may further comprise a long period fiber grating for converting the second radiation beam and the first radiation beam in the fiber core into the inner cladding of the fiber.

It should be understood that the above "conversion" may also be "extraction".

By way of example and not limitation, the beam splitter serves as another part of the pump recovery unit 120 for extracting cladding light, i.e. residual pump light, in the first optical path from the input end of the beam splitter to the output end of the beam splitter and from the output end of the beam splitter to the second optical path.

Further, the cladding light circulates to the beam combiner through the second optical path and is co-injected into the laser resonance unit 110 together with the externally input multimode pump laser. The input end of the beam splitter is composed of double-clad optical fibers with the same specification as the tail optical fibers of the low-reflection fiber gratings, and the output end of the beam splitter is composed of 1 double-clad optical fiber and N multimode recovery optical fibers with the same specification. Wherein N is a positive integer.

It should be understood that the beam splitter recovers cladding light from the laser resonator 110, and the recovered cladding light is recycled into the beam combiner through N multimode recovery fibers at the output end of the beam splitter, and the flow direction of the cladding light is shown by the arrow in fig. 3 (a).

By way of example and not limitation, a mode stripper is provided as part of the laser output unit 130 to strip residual pump laser light that is not recovered by the beam splitter to achieve output of single-mode laser light within the first wavelength range generated by the laser resonator unit 110.

Each part in (a) of fig. 3 forms a multimode pump laser injection and cladding light recycling system without the first radiation beam and the second radiation beam, which can greatly improve the pump efficiency and increase the output power of the single-wavelength laser generator 100 without affecting the first laser oscillation.

In addition to the single wavelength laser generator 100 shown in fig. 3 (a) being capable of realizing a one-way cycle of cladding light recovery, the single wavelength laser generator 100 may also be capable of realizing a two-way cycle of cladding light, as shown in fig. 3 (b).

Specifically, as an example and not by way of limitation, a combiner is used to combine the externally input multimode pump laser light and the multimode pump laser light in the second optical path recovery cladding light and inject into the laser resonance unit 110. The input end of the beam combiner consists of 1 multimode pump fiber and N/2 multimode recovery fibers with the same specification, and the head and the tail of each multimode recovery fiber are connected with the input end of the beam combiner. The output end of the beam combiner is composed of 1 double-clad optical fiber or coreless optical fiber. Wherein N is a positive integer.

It should be understood that the N/2 multimode recovery fibers with the same specification are used for not only inputting the cladding light recovered from the beam splitter to the input end of the beam combiner, but also outputting the cladding light recovered from the beam splitter from the input end of the beam combiner, so as to achieve bidirectional circulation of the cladding light at the input end of the beam combiner.

It should be appreciated that when the cladding light is recycled in both directions, the beam splitter extracts the cladding light into the second optical path, and then the cladding light is injected into the first optical path from the second optical path to be transmitted to the beam combiner end, and is transmitted only in the cladding of the first optical path fiber; thus, unlike the one-way circulation of the cladding light, the cladding light extracted by the beam splitter is transmitted only in the second optical path to the combiner end.

At this time, the blocking subunit needs to have a bidirectional blocking function for the first radiation beam and the second radiation beam. The first radiation beam and the second radiation beam from the beam combiner end are blocked, the first radiation beam and the second radiation beam in the cladding light recovered by the beam splitter are blocked, and the blocking subunit can pass through the pump light in a nondestructive or low-loss way.

The blocking subunit may include a narrow band filter or a dichroic mirror or a tilted fiber bragg grating.

Further, the cladding light is injected from the second optical path into the first optical path to be transmitted to the combiner end, and is transmitted only in the cladding of the first optical path fiber. The input end of the beam splitter is composed of double-clad optical fibers with the same specification as the tail optical fibers of the low-reflection fiber gratings, the output end of the beam splitter is composed of 1 double-clad optical fiber and N/2 multimode recovery optical fibers with the same specification, and the head and the tail of each multimode recovery optical fiber are connected with the output end of the beam splitter. Wherein N is a positive integer.

It should be understood that the N/2 multimode recovery fibers are used not only for outputting the cladding light recovered by the beam splitter from the output end of the beam splitter, but also for inputting the cladding light recovered by the beam splitter to the output end of the beam splitter, thereby achieving bidirectional circulation of the cladding light at the output end of the beam splitter.

The other contents refer to fig. 3 (a) above, and are not described here again.

By converting cladding light in the single-wavelength laser generator 100 from a unidirectional circulation mode to a bidirectional circulation mode, head-to-tail connection among devices does not exist, so that the integration level is higher, the volume is smaller, and the structural simplification of the single-wavelength laser generator 100 can be realized; in addition, compared with a unidirectional circulation mode, the beam combiner and the beam splitter in the bidirectional circulation can be respectively and independently completed in the manufacturing process, so that the subsequent fiber melting operation is reduced, the process simplification can be realized, and the manufacturing cost is reduced; finally, the bi-directional cycling approach can achieve higher pumping efficiency and thus overall electro-optic efficiency.

The structure and function of an exemplary blocking subunit of the present application will now be described in detail with reference to fig. 3 (c).

The structure shown in fig. 3 (c) is one implementation of the blocking subunit in the single wavelength laser generator 100 of fig. 3 (a) and 3 (b).

The optical fibers at the two ends of the blocking subunit are respectively identical to the tail fiber specifications of the output end of the beam combiner and the high-reflection fiber grating which are connected, and can be double-clad optical fibers or coreless optical fibers, etc., which are not limited by the application.

In fig. 3 (c), the dashed arrow indicates ASE of the first radiation beam and the second wavelength range, and the solid arrow indicates multimode pump laser. The optical film in the ASE blocking subunit may be a narrow-band filter, a dichroic mirror, or an inclined bragg fiber grating, and the specific structure of the intermediate optical film is not limited in the present application, as long as the above-described function of blocking a specific light wave can be achieved.

In particular, the optical film allows only a very narrow range of light waves to pass through, i.e. only pump light can pass through from the combiner end to the grating end.

It will be appreciated that either for the case of unidirectional recycling of cladding light in fig. 3 (a) or for the case of bi-directional recycling of cladding light in fig. 3 (b), the multimode pump laser or cladding light in the pump wavelength range can pass through the optical film in the middle of the blocking subunit without loss or with low loss.

In addition, the optical film in the middle of the blocking subunit is used for reflecting ASE of the first radiation beam and the second wavelength range, namely the ASE of the first radiation beam and the second wavelength range cannot pass through smoothly, and the isolation is more than or equal to 20dB.

Optionally, the diffuse reflection structures on the upper side and the lower side of the blocking subunit eliminate the reflected light waves, so as to prevent light pollution.

Fig. 4 (a) shows another exemplary configuration of the single wavelength laser generator 100 of the present application. Wherein the blocking sub-unit in the pump recovery unit 120 is arranged on the second optical path, also called the sub-optical path, as shown in fig. 4 (a).

At this point, the cladding light at the combiner input remains only for light waves in the pump laser band, since the cladding light has been blocked by the blocking subunit when transmitted in the multimode recovery fiber, both the first radiation beam and the second radiation beam.

In this case, the optical fibers at both ends of the blocking subunit may be multimode optical fibers.

For other matters, reference is made to the description related to fig. 3 (a), and details are not repeated here.

By placing the blocking sub-units on the second optical path, the interference of other light sources in the cladding light on the multimode pump light can be reduced, while the sustainable power index and isolation index of a single blocking sub-unit can be reduced to 1/N of that of the single blocking sub-unit placed on the main optical path.

In addition to the single wavelength laser generator 100 shown in fig. 4 (a) being capable of realizing a one-way cycle of cladding light recovery, the single wavelength laser generator 100 may correspondingly be capable of realizing a two-way cycle of cladding light as shown in fig. 4 (b).

Specifically, a blocking subunit is disposed on the N/2 multimode recovery fibers, the blocking subunit blocking the first radiation beam and the second radiation beam of the cladding light recovered from the beam splitter output from the input end of the beam combiner.

At this time, the blocking subunit needs to have a bidirectional blocking function for the first radiation beam and the second radiation beam generated by the dual-cladding ytterbium-doped fiber, that is, both ends of the blocking subunit can block the first radiation beam and the second radiation beam in the cladding light recovered from the beam splitter and output from the input end of the beam combiner, and both ends of the blocking subunit can pass through the pump light without damage or with low loss.

Other contents refer to the descriptions related to fig. 3 (b) and fig. 4 (a), and are not repeated here.

By converting the cladding light in the single wavelength laser generator 100 of fig. 4 (a) from a unidirectional circulation mode to a bidirectional circulation mode and disposing the blocking subunits on each multimode recovery fiber respectively, not only the interference of other light sources in the cladding light on multimode pump light can be reduced, but also the sustainable power index and isolation index of a single blocking subunit are only 2/N of that of the single blocking subunit placed on the main optical path at maximum.

The structure and function of another blocking subunit of the present application will be described in detail below with reference to fig. 4 (c).

The structure shown in fig. 4 (c) is one implementation of the blocking subunit in the single wavelength laser generator 100 shown in fig. 4 (a) and fig. 4 (b).

The blocking subunit is arranged on the multimode recovery optical fiber of the second optical path, and the optical fibers at the two ends of the blocking subunit are multimode optical fibers and have the same specification as the multimode recovery optical fibers of the beam combiner and the beam splitter.

In fig. 4 (c), the dashed arrow indicates ASE of the first radiation beam and the second wavelength range, and the solid arrow indicates multimode pump light. The optical film in the middle of the ASE blocking subunit may be a narrow-band filter or a dichroic mirror or an inclined bragg fiber grating, and the specific structure of the intermediate optical film in the present application is not limited as long as the above-described functions can be achieved.

The narrow-band filter, the dichroic mirror or the inclined Bragg fiber grating only allows light waves in a very narrow range to pass through, namely only allows light which accords with the pumping wavelength in the cladding light to be injected into the beam combiner end from the beam splitter end.

It will be appreciated that light of the pump wavelength in the cladding light can pass through the optical film in the middle of the blocking subunit without loss or with low loss, either for the case of unidirectional recycling of the cladding light in fig. 4 (a) or for the case of bi-directional recycling of the cladding light in fig. 4 (b).

In addition, the optical film in the middle of the blocking subunit is used for reflecting a first radiation beam and a second radiation beam generated by the double-cladding ytterbium-doped optical fiber, namely ASE in the first radiation beam and the second wavelength range cannot pass through smoothly, and the isolation is more than or equal to 20dB; meanwhile, the diffuse reflection structures on the upper side and the lower side eliminate reflected light waves, and prevent light pollution.

Fig. 5 (a) shows a schematic structural diagram of a single-wavelength laser generator 100 according to the present application. The blocking sub-unit in the pump recovery unit 120 is disposed on the second optical path as the blocking sub-unit in fig. 4 (a), but unlike the blocking sub-unit in fig. 4 (a), the single clad multimode optical fibers at both ends of the blocking sub-unit adopt an array arrangement, as shown in fig. 5 (a).

At this time, the cladding light at the combiner input end only remains in the pump light band range because the cladding light has been blocked by the blocking subunit from the first and second radiation beams while propagating in the multimode recovery fiber array.

In this case, the optical fibers at both ends of the blocking subunit may be multimode fiber arrays.

By placing the blocking subunit on the second optical path, interference of other light sources in the cladding light on the multimode pump light can be reduced; although the single-cladding multimode optical fibers at the two ends of the blocking subunit adopt an array arrangement form, the power index and the isolation index required to be born by the unit area of the blocking subunit can still be reduced to 1/N of that of the blocking subunit placed on the first optical path.

The blocking subunit is arranged on the second optical path, and the single-cladding multimode fibers at two ends of the blocking subunit adopt an array arrangement mode, so that the integration level of the single-wavelength laser generator 100 is higher, and the packaging cost is reduced.

In addition to the single wavelength laser generator 100 shown in fig. 5 (a) being capable of realizing a one-way cycle of cladding light recovery, the single wavelength laser generator 100 may also be capable of realizing a two-way cycle of cladding light, as shown in fig. 5 (b).

Specifically, the blocking subunit is arranged on N/2 multimode recovery fibers, and the single-cladding multimode fibers at two ends of the blocking subunit adopt an array arrangement mode.

By converting the cladding light in the single-wavelength laser generator 100 shown in fig. 5 (a) from a unidirectional circulation mode to a bidirectional circulation mode, and arranging the blocking subunits in the N/2 multimode recovery fibers and the single-cladding multimode fibers at two ends of the blocking subunits respectively in an array mode, the interference of other light sources in the cladding light on multimode pump light can be reduced, the bearable power index and the isolation index of the single blocking subunit are only 2/N of that of the single blocking subunit when the single blocking subunit is placed on the first optical path, and the integration level of the single-wavelength laser generator 100 is higher, and the packaging cost is reduced.

The structure and function of a further blocking subunit according to the present application will now be described in detail with reference to fig. 5 (c).

The structure shown in fig. 5 (c) is one implementation of the blocking subunit in the single wavelength laser generator 100 shown in fig. 5 (a) and 5 (b).

Because the blocking subunit is arranged on the multimode recovery optical fiber of the second optical path, the optical fibers at the two ends of the ASE blocking subunit are single-cladding recovery optical fibers and have the same specification as the multimode recovery optical fibers of the beam combiner and the beam splitter.

In addition, in the case of fig. 5 (a), the ASE blocking subunit is formed by integrating N single-clad recovery fibers in an array arrangement manner at both ends; for the case of fig. 5 (b), both ends of the blocking subunit are respectively formed by integrating N/2 single-clad recovery fibers through an array arrangement form.

In fig. 5 (c), the dashed arrow indicates ASE of the first radiation beam and the second wavelength range, and the solid arrow indicates pump laser. The optical film in the middle of the blocking subunit may be a narrow-band filter or a dichroic mirror or an inclined bragg fiber grating, and the specific structure of the intermediate optical film is not limited in the present application as long as the above-described functions can be achieved.

It will be appreciated that light of the pump wavelength in the cladding light can pass through the diagonal squares in the middle of the ASE-blocking subunit without loss or with low loss, both for the case of unidirectional recycling of cladding light in fig. 5 (a) and for the case of bi-directional recycling of cladding light in fig. 5 (b).

Fig. 5 (d) shows a schematic diagram of two arrangements of the optical fibers at both ends of the blocking subunit in fig. 5 (c).

Specifically, the arrangement array of the optical fibers at two ends of the blocking subunit may be a one-dimensional linear array or a two-dimensional array, and may be selected and arranged according to a specific system, which is not limited in the present application.

Through various embodiments of the application, the conversion efficiency of 980nm laser can be greatly improved, and the output power and the signal-to-noise ratio of 980nm wave band laser signals can be improved.

Fig. 6 shows a schematic structural diagram of a single wavelength laser generator 100 of the present application.

The parameters such as the linewidth, fineness, and quality of the laser beam of the first laser output from the single-wavelength laser generator 100 of fig. 3 to 5 are determined by the multimode pump laser pump and the cavity structure oscillation of the laser resonator 110, and the single-wavelength laser generator 100 shown in fig. 6 adds the external input of the first laser seed.

The parameters of the line width, fineness, laser beam quality, etc. of the first laser light output from the single wavelength laser generator 100 shown in fig. 6 can be adjusted by the parameters of the first laser seed input from the outside.

It should be understood that the wavelength of the externally input laser seed is consistent with the wavelength to be amplified, and the application is not limited to the wavelength of the externally input laser seed.

Additionally, a circulator for outputting the externally input first laser seed to the laser resonator unit 110 and amplifying the first laser generated with the multimode pump laser pumping in the laser resonator unit 110 is also added in the single wavelength laser generator 100.

Further, the obtained first laser light is input into the circulator and output from the circulator.

It should be understood that the above-mentioned input process of the first laser seed from the circulator is equivalent to functioning as a low reflection fiber grating, both of which are for inputting the first laser into the double-clad ytterbium-doped fiber again for amplification.

The other contents may refer to the contents in (a) of fig. 3 described above.

Fig. 7 is a schematic flow chart of an example of a method 200 of generating a single wavelength laser according to the present application. As shown in fig. 7, the method 200 includes the steps of:

At S210, at least one multimode pump laser is input to the laser resonator unit.

This process can be achieved by controlling the multimode pump described above. Alternatively, the process may be performed automatically by the multimode pump described above.

At S230, a first radiation beam generated by at least one multimode pump laser pump is selected and a first laser is formed, and the first laser is limited to be repeatedly oscillated in the laser resonance unit 110.

This process may be implemented by controlling the laser resonance unit 110 described above, or the process may be implemented by being automatically performed by the laser resonance unit 110 described above.

At S250, the first radiation beam and the second radiation beam are blocked.

This process may be accomplished by controlling the blocking sub-unit in the pump recovery unit 120 described above. Alternatively, the process may be automatically performed by the blocking subunit in the pump recovery unit 120 described above. For example, by adjusting the reflection wavelength range of the narrow band filter or the dichroic mirror or the tilted bragg grating in the blocking subunit, the first radiation beam and the second radiation beam can be reflected off, allowing only light waves conforming to the pump light wavelength range to pass through.

Alternatively, the step S250 may be implemented before the multimode pump laser is injected into the laser resonance unit 110, or may be implemented after the multimode pump laser is injected into the laser resonance unit 110, which is not limited by the present application.

At S270, the first laser light generated by the laser resonance unit 110 is output.

This process may be implemented by controlling the above-described laser output unit 130, or the process may be implemented by being automatically performed by the above-described laser output unit 130.

It will be appreciated that the pump laser pumps in the laser resonator unit 110 to generate metastable ytterbium ions which are stimulated to radiate to generate a first beam of radiation which forms a first laser under the confinement of the laser resonator unit 110 structure. And the laser with the first wavelength is continuously and stably output after being amplified by power under the amplification effect of ytterbium ions of the double-cladding ytterbium-doped optical fiber.

At S290, the residual multimode pump laser light is recovered.

This process may be implemented by controlling the beam splitter in the pump recovery unit 120 described above, or the process may be automatically performed by the beam splitter in the pump recovery unit 120 described above.

In S295, the residual multimode pump laser light recovered in S290 is combined with the externally input multimode pump laser light and input to the laser resonance unit in S210.

This process may be implemented by controlling the beam combiner described above, or the process may be automatically performed by the beam combiner described above.

It is understood that recycling of cladding light is achieved through this step, thereby improving the efficiency of use of pump light.

The process of fig. 7 described above may be implemented by a control controller. Alternatively, the process of FIG. 7 described above may be implemented by the controller and detector cooperating. That is, the controller may read the software program in the storage unit, interpret and execute the instructions of the software program, process the data of the software program, and further control each device of the single wavelength light source generator 100 to perform the respective functions, thereby performing the above-described method 200.

For example, the controller may be implemented by a processor, and the processor may include a central processor mainly for controlling the entire terminal device, executing a software program, and processing data of the software program.

It should be appreciated that in embodiments of the application, the processor may be a central processing unit (central processing unit, CPU), other general purpose processor, digital signal processor (digital signal processor, DSP), application specific integrated circuit (application specific integrated circuit, ASIC), off-the-shelf programmable gate array (field programmable gate array, FPGA) or other programmable logic device, discrete gate or transistor logic device, discrete hardware components, or the like. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.

It should also be appreciated that the memory in embodiments of the present application may be either volatile memory or nonvolatile memory, or may include both volatile and nonvolatile memory. The nonvolatile memory may be a read-only memory (ROM), a Programmable ROM (PROM), an Erasable PROM (EPROM), an electrically Erasable EPROM (EEPROM), or a flash memory. The volatile memory may be random access memory (random access memory, RAM) which acts as an external cache. By way of example but not limitation, many forms of random access memory (random access memory, RAM) are available, such as Static RAM (SRAM), dynamic Random Access Memory (DRAM), synchronous Dynamic Random Access Memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced Synchronous Dynamic Random Access Memory (ESDRAM), synchronous Link DRAM (SLDRAM), and direct memory bus RAM (DR RAM).

The acts or methods performed by the controller may be implemented in whole or in part by software, hardware, firmware, or any other combination. When implemented in software, the acts or methods performed by the controller may be implemented in whole or in part in the form of a computer program product. The computer program product comprises one or more computer instructions or computer programs. When the computer instructions or computer program are loaded or executed on a computer, the processes or functions described in accordance with embodiments of the present application are produced in whole or in part. The computer may be a general purpose computer, a special purpose computer, a computer network, or other programmable apparatus. The computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium, for example, the computer instructions may be transmitted from one website site, computer, server, or data center to another website site, computer, server, or data center by wired (e.g., infrared, wireless, microwave, etc.). The computer readable storage medium may be any available medium that can be accessed by a computer or a data storage device such as a server, data center, etc. that contains one or more sets of available media. The usable medium may be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium. The semiconductor medium may be a solid state disk.

Fig. 8 is a schematic structural diagram of a possible light emitting device according to an embodiment of the present application. Specifically, the light emitting device 300 includes a single wavelength laser generator 100, a tunable optical splitter 301, and optical amplifiers (302 a to 302 d) 302. The light emitting device 100 is a single wavelength emitting device. The single wavelength light source generator 100 generates a high-power light wave of a first wavelength, and inputs the light wave to the corresponding tunable optical splitter 301. The tunable optical splitter 301 may split the high power optical wave of the first wavelength into multiple optical waves that are input as pump light sources to a corresponding plurality of optical amplifiers (302 a-302 d).

Optionally, the multiple light waves may be used as pump light sources of erbium-doped fiber amplifiers (erbium-doped optical fiber amplifier, EDFA), bismuth-doped fiber amplifiers (bismputh-doped optical fiber amplifier, BDFA), etc., and the type of the amplifier is not limited in the present application, so long as the multiple light waves obtained by implementing the embodiment of the present application are within the protection scope of the present application.

Alternatively, the multiple light waves obtained through the tunable optical splitter 301 may also be used as pump light sources of different levels of a single optical amplifier.

It should be noted that the single wavelength laser generator 100 may be replaced by the structure of any one of the foregoing single wavelength laser generators in fig. 1, 3 (a), 3 (b), 4 (a), 4 (b), 5 (a), 5 (b) or 6, or may be an alternative implementation provided in the foregoing description.

Specifically, the light emitting apparatus 300 may be the aforementioned transmitting-side device and/or receiving-side device. Alternatively, the light emitting device 300 may be a light module, for example: an optical transmitter or an optical transceiver.

It should be understood that, in various embodiments of the present application, the sequence numbers of the foregoing processes do not mean the order of execution, and the order of execution of the processes should be determined by the functions and internal logic thereof, and should not constitute any limitation on the implementation process of the embodiments of the present application.

Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application. It will be clear to those skilled in the art that, for convenience and brevity of description, specific working procedures of the above-described systems, apparatuses and units may refer to corresponding procedures in the foregoing method embodiments, and are not repeated herein. In the several embodiments provided by the present application, it should be understood that the disclosed systems, devices, and methods may be implemented in other manners. For example, the apparatus embodiments described above are merely illustrative, e.g., the division of the units is merely a logical function division, and there may be additional divisions when actually implemented, e.g., multiple units or components may be combined or integrated into another system, or some features may be omitted or not performed. Alternatively, the coupling or direct coupling or communication connection shown or discussed with each other may be an indirect coupling or communication connection via some interfaces, devices or units, which may be in electrical, mechanical or other form.

The units described as separate units may or may not be physically separate, and units shown as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment. In addition, each functional unit in the embodiments of the present application may be integrated in one processing unit, or each unit may exist alone physically, or two or more units may be integrated in one unit. The functions, if implemented in the form of software functional units and sold or used as a stand-alone product, may be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application may be embodied essentially or in a part contributing to the prior art or in a part of the technical solution, in the form of a software product stored in a storage medium, comprising several instructions for causing a computer device (which may be a personal computer, a server, a network device, etc.) to perform all or part of the steps of the method according to the embodiments of the present application. And the aforementioned storage medium includes: various media capable of storing program codes, such as a U disk, a mobile hard disk, a read-only memory, a random access memory, a magnetic disk or an optical disk.

The foregoing is merely illustrative of the present application, and the present application is not limited thereto, and any person skilled in the art will readily recognize that variations or substitutions are within the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A single wavelength laser generator comprising:

a laser resonance unit including a first input port for inputting at least one multimode pump laser beam, a first output port for processing the at least one multimode pump laser beam to output a first beam including a first radiation beam generated after the at least one multimode pump laser beam is pumped in the laser resonance unit, a second radiation beam including a beam generated after the first laser beam is oscillated in the laser resonance unit, and a residual multimode pump laser beam, which is different from the second radiation beam in a wavelength range of the first radiation beam, from the first output port;

The pump recycling unit comprises a second input port, a third output port and a blocking subunit, wherein the second input port is used for inputting the first beam, the blocking subunit is used for blocking the first radiation beam and the second radiation beam included in the first beam, the third output port is used for outputting the residual multimode pump laser, the residual multimode pump laser is input into the first input port of the laser resonance unit, and the second input port of the pump recycling unit is optically connected with the first output port of the laser resonance unit;

and the laser output unit is used for outputting the first laser.

2. The single wavelength laser generator of claim 1, the at least one multimode pump laser comprising: the residual multimode pump laser light and externally input multimode pump laser light.

3. The single wavelength laser generator of claim 1 or 2, wherein the multimode pump laser has a wavelength in the range 900nm to 970nm, the first laser and the first radiation beam have a wavelength in the range 970nm to 990nm, and the second radiation beam has a wavelength in the range 1000nm to 1100nm.

4. A single wavelength laser generator according to any one of claims 1 to 3, wherein the pump recovery unit comprises: the input end of the beam splitter is connected with 1 double-clad optical fiber, the output end of the beam splitter is connected with 1 double-clad optical fiber and N multimode recovery optical fibers with the same specification, wherein N is a positive integer,

the beam splitter is used for inputting the first light beam of a first light path to a second light path, the first light path comprises double-cladding ytterbium-doped optical fibers, and the second light path comprises M multimode recovery optical fibers with the same specification, wherein M is a positive integer.

5. The single wavelength laser generator of any one of claims 1 to 4, wherein the input and output ends of the blocking subunit are respectively connected to a double-clad optical fiber, a coreless optical fiber, a multimode recycling optical fiber or a multimode optical fiber array, and wherein the input end of the blocking subunit and the output end of the blocking subunit are connected to the same optical fiber specification.

6. The single wavelength laser generator of any one of claims 1 to 5, further comprising:

the input end of the beam combiner is connected with 1 multimode pumping fiber and N multimode recovery fibers with the same specification, the output end of the beam combiner is connected with 1 double-clad fiber or coreless fiber, wherein N is a positive integer,

The beam combiner is used for combining the at least one beam of multimode pump light and inputting the at least one beam of multimode pump light into the laser resonance unit.

7. The single wavelength laser generator of any one of claims 1 to 6, wherein the laser resonator unit comprises:

at least one pair of fiber gratings comprising a high reflection grating fiber and a low reflection grating, wherein,

the high reflection fiber grating has a reflectivity for the first laser light greater than a first threshold, a reflectivity for the first radiation beam and the second radiation beam less than a second threshold,

the reflectivity of the low reflection fiber grating to the first laser is smaller than a third threshold value, and the reflectivity to the first radiation beam and the second radiation beam is smaller than a fourth threshold value.

8. The single wavelength laser generator of any one of claims 1 to 7, wherein the laser resonator unit further comprises:

and the long-period fiber grating is used for converting the first radiation beam and the second radiation beam in the fiber core into the fiber cladding.

9. The single wavelength laser generator of any one of claims 1 to 8, wherein the laser resonator unit further comprises:

The double-clad ytterbium-doped fiber is used for amplifying the first laser, and comprises any one of the following components:

10. The single wavelength laser generator of any one of claims 1 to 9, wherein the laser output unit comprises an isolator or a beam splitter.

11. A method of generating a single wavelength laser, comprising:

processing at least one multimode pump laser to obtain a first beam and a first laser, wherein the first beam comprises a first radiation beam, a second radiation beam and residual multimode pump laser, the first radiation beam is generated by pumping the at least one multimode pump laser in a laser resonance unit, the second radiation beam comprises a beam generated by oscillating the first laser in the laser resonance unit, and the second radiation beam comprises a beam generated by pumping the at least one multimode pump laser in the laser resonance unit, the first radiation beam and the second radiation beam are different in wavelength range, and the first laser is generated by oscillating the first radiation beam in the laser resonance unit;

Blocking the first radiation beam and the second radiation beam included in the first beam and inputting the residual multimode pump laser light to the laser resonator unit;

outputting the first laser.

12. The method of claim 11, wherein the at least one multimode pump laser comprises:

the residual multimode pump laser light and externally input multimode pump laser light.

13. The method of claim 11 or 12, wherein the multimode pump laser has a wavelength in the range 900nm to 970nm, the first laser and the first radiation beam have a wavelength in the range 970nm to 990nm, and the second radiation beam has a wavelength in the range 1000nm to 1100nm.

14. The method according to any one of claims 11 to 13, further comprising:

inputting the first light beam in a first light path to a second light path, wherein the first light path comprises double-cladding ytterbium-doped optical fibers, and the second light path comprises M multimode recovery optical fibers with the same specification, wherein M is a positive integer.

15. The method according to any one of claims 11 to 14, further comprising:

And combining the at least one beam of multimode pump laser and inputting the at least one beam of multimode pump laser into the laser resonance unit.

16. The method according to any one of claims 11 to 15, wherein the first laser is generated by oscillation of the first radiation beam in a laser resonator unit comprising:

the reflectivity of the high reflection fiber grating for the first wavelength laser is greater than a first threshold, the reflectivity for the first radiation beam and the second radiation beam is less than a second threshold,

17. The method according to any one of claims 11 to 16, further comprising:

the first radiation beam and the second radiation beam in the fiber core are converted into the fiber cladding.

18. The method of any one of claims 11 to 17, wherein the laser resonator unit further comprises:

the double-cladding ytterbium-doped optical fiber is used for amplifying the first laser, and comprises any one of the following components:

19. An optical transmitting device comprising the single wavelength laser generator of any one of claims 1-10, a tunable optical splitter, and an optical amplifier, wherein,

the adjustable optical splitter is used for dividing the single-wavelength laser generated by the single-wavelength laser generator into multiple paths of light waves, and respectively injecting the multiple paths of light waves as pump laser into the optical amplifier;

the optical amplifier amplifies the light wave of a specific wave band using the pump laser pump.