Self-starting Mamyshev fiber oscillator based on spectral modulation

Abstract

The present invention discloses a self-starting Mamyshev fiber laser oscillator based on spectral modulation, comprising: two spectral filters, two pump sources, two wavelength division multiplexers, two fiber gain stretchers, two output couplers, and two optical isolators. The fiber gain stretcher comprises a gain fiber and a passive fiber. The self-starting Mamyshev fiber oscillator device can effectively improve the self-starting performance of the Mamyshev oscillator, will not increase the complexity of the laser structure, is conducive to integrated design, and maintains a relatively high output energy.

Description

Technical Field

[0001] The present disclosure relates to the technical field of optical fiber lasers, and in particular to a self-starting Mamyshev optical fiber oscillator device based on spectral modulation. Background Art

[0002] Compared with traditional solid-state mode-locked lasers, fiber mode-locked lasers have the advantages of high gain, simple structure, good beam quality, and good ring mirror stability. However, due to the pulse distortion caused by the nonlinear effect of the fiber, the pulse energy output by the fiber mode-locked laser is much lower than that of the solid-state mode-locked laser. The Mamyshev oscillator based on pulse re-amplification and pulse reshaping increases the pulse energy directly output by the fiber mode-locked laser to the μJ level. After de-chirping, the pulse width is 41fs, and the corresponding peak power is 13MW. This result is comparable to that of solid-state mode-locked lasers.

[0003] However, the Mamyshev oscillator cannot achieve self-starting operation and needs to inject a seed pulse or perform external electrical modulation when starting. In order to make the Mamyshev oscillator self-starting, it is necessary to introduce auxiliary saturation absorption mechanisms such as nonlinear polarization rotation effect and nonlinear fiber loop mirror into the Mamyshev oscillator to reduce the mode-locking threshold and generate ultrashort pulse sequences. In addition, reducing the wavelength difference between the two filters in the Mamyshev oscillator cavity can also reduce the mode-locking threshold and achieve self-starting operation.

[0004] Mamyshev oscillators are usually unable to achieve self-starting and require the injection of seed pulses or external electrical modulation to trigger the mode-locking threshold and form a mode-locked pulse, which is inconvenient to use. If one wants to achieve self-starting operation of the Mamyshev oscillator, it is necessary to introduce an auxiliary saturation absorption mechanism in the laser cavity to lower the mode-locking threshold, which increases the complexity of the laser structure. Self-starting operation can be achieved by reducing the wavelength difference between the two filters in the Mamyshev oscillator cavity, but the laser cannot obtain higher pulse energy. Summary of the invention

[0005] 1. Technical issues to be resolved

[0006] Based on the above problems, the present disclosure provides a self-starting Mamyshev fiber oscillator device based on spectral modulation, in order to solve at least one of the above-mentioned technical problems.

[0007] (II) Technical solution

[0008] The present disclosure provides a self-starting Mamyshev fiber laser oscillator based on spectral modulation, comprising:

[0009] Two spectral filters, namely a first spectral filter and a second spectral filter, wherein the first spectral filter is used to output a first narrow spectrum laser, and the second spectral filter is used to output a second narrow spectrum laser;

[0010] Two pump sources, namely a first pump source and a second pump source, are used to output a first pump laser and a second pump laser respectively;

[0011] Two wavelength division multiplexers, namely a first wavelength division multiplexer and a second wavelength division multiplexer, wherein the first wavelength division multiplexer is used to receive the first pump laser and the second narrow spectrum laser, and couple them to form a first coupled laser, and the second wavelength division multiplexer is used to receive the second pump laser and the first narrow spectrum laser, and couple them to form a second coupled laser;

[0012] Two optical fiber gain stretchers, namely a first optical fiber gain stretcher and a second optical fiber gain stretcher, wherein the first optical fiber stretcher is used to receive the first coupled laser, increase its pulse energy, and stretch its spectrum to form a first wide-spectrum laser, and the second optical fiber gain stretcher is used to receive the second coupled laser, increase its pulse energy, and stretch its spectrum to form a second wide-spectrum laser;

[0013] two output couplers, namely a first output coupler and a second output coupler, wherein the first output coupler is used to receive the first broad-spectrum laser and output a portion of the first broad-spectrum laser according to a set ratio, and the second output coupler is used to receive the second broad-spectrum laser and output a portion of the second broad-spectrum laser according to a set ratio; and

[0014] Two optical isolators, namely a first optical isolator and a second optical isolator, the first optical isolator is used to receive the broad-spectrum laser light passing through the first output coupler and ensure that it passes through in one direction, thereby forming a first unidirectional broad-spectrum laser light, while isolating the residual light transmitted in the reverse direction, and the second optical isolator is used to receive the broad-spectrum laser light passing through the first output coupler and ensure that it passes through in one direction, thereby forming a second unidirectional broad-spectrum laser light, while isolating the residual light transmitted in the reverse direction;

[0015] Among them, the input end of the first spectral filter is connected to the first optical isolator, which is used to receive the first unidirectional broadband laser and allow the part that meets the set wavelength to pass through, forming the first narrow spectrum laser, and the input end of the second spectral filter is connected to the second optical isolator, which is used to receive the second unidirectional broadband laser and allow the part that meets the set wavelength to pass through, forming the second narrow spectrum laser, thereby forming a self-starting Mamyshev fiber laser oscillation circuit.

[0016] In the disclosed embodiment, the first optical fiber gain stretcher includes a first gain optical fiber and a first passive optical fiber. The first gain optical fiber is used to amplify the power of the first coupled laser, and at the same time initially broaden its spectrum and transmit it to the first passive optical fiber for further broadening to form the first wide-spectrum laser.

[0017] In the embodiment of the present disclosure, the second broadening fiber device includes a second gain fiber and a second passive fiber. The second gain fiber is used to amplify the power of the second coupled laser, and at the same time initially broaden its spectrum and transmit it to the second passive fiber for further broadening to form the second broadened laser.

[0018] Furthermore, the center wavelength of the gain spectrum of the first gain optical fiber matches the working wavelength of the second spectrum filter to obtain a higher gain.

[0019] Furthermore, the center wavelength of the gain spectrum of the second gain optical fiber matches the working wavelength of the first spectrum filter to obtain a higher gain.

[0020] Furthermore, the first passive optical fiber can utilize its own nonlinearity to cause the spectrum to undergo frequency conversion to generate new spectrum components, while trying to concentrate the new spectrum components in the filtering band of the first spectrum filter.

[0021] Furthermore, the second passive optical fiber can utilize its own nonlinearity to cause the spectrum to undergo frequency conversion to generate new spectrum components, while trying to concentrate the new spectrum components in the filtering band of the second spectrum filter.

[0022] In the embodiments of the present disclosure, the first passive optical fiber or the second passive optical fiber includes ordinary single-mode optical fiber, dispersion-compensating optical fiber, highly nonlinear optical fiber and photonic crystal optical fiber.

[0023] (III) Beneficial effects

[0024] It can be seen from the above technical solutions that the self-starting Mamyshev fiber oscillator based on spectral modulation disclosed in the present invention has at least one or part of the following beneficial effects:

[0025] (1) The gain spectrum and frequency conversion spectrum generated in the Mamyshev oscillator device are adjusted to match the filtering band of the spectral filter;

[0026] (2) lowering the mode-locking threshold of the Mamyshev oscillator; and

[0027] (3) The self-starting operation of the Mamyshev oscillator was realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Schematic diagram of the principle of a self-starting Mamyshev fiber oscillator based on spectral modulation in an embodiment of the present disclosure.

[0029] [Description of the main component symbols of the embodiment of the present disclosure in the accompanying drawings]

[0030] 1. First Pump Source

[0031] 2 The first wavelength division multiplexer

[0032] 3. First gain fiber

[0033] 4 The first passive optical fiber

[0034] 5 First output coupler

[0035] 6 The first optical isolator

[0036] 7. First spectral filter

[0037] 8 Second Pump Source

[0038] 9 Second wavelength division multiplexer

[0039] 10 Second gain fiber

[0040] 11 Second passive optical fiber

[0041] 12 Second output coupler

[0042] 13. Second optical isolator

[0043] 14 Second spectral filter DETAILED DESCRIPTION

[0044] The present disclosure provides a self-starting Mamyshev fiber oscillator device based on spectral modulation, which can effectively improve the self-starting performance of the Mamyshev oscillator without increasing the complexity of the laser structure, and is conducive to integrated design while maintaining a relatively high output energy.

[0045] In order to make the objectives, technical solutions and advantages of the present disclosure more clearly understood, the present disclosure is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0046] In the embodiment of the present disclosure, a self-starting Mamyshev fiber oscillator device based on spectral modulation is provided, such as Figure 1As shown, the self-starting Mamyshev fiber oscillator device includes: two spectrum filters, namely a first spectrum filter 7 and a second spectrum filter 14, wherein the first spectrum filter 7 is used to output a first narrow spectrum laser, and the second spectrum filter 14 is used to output a second narrow spectrum laser; two pump sources, namely a first pump source 1 and a second pump source 2, respectively, which are used to output a first pump laser and a second pump laser; two wavelength division multiplexers, namely a first wavelength division multiplexer 2 and a second wavelength division multiplexer 9, wherein the first wavelength division multiplexer 2 is used to receive the first pump laser and the second narrow spectrum laser, and couple them to form a first coupled laser, and the second wavelength division multiplexer 9 is used to receive the second pump laser and the first narrow spectrum laser, and couple them to form a second coupled laser; two fiber gain stretchers, namely a first fiber gain stretcher and a second fiber gain stretcher, wherein the first fiber gain stretcher is used to receive the first coupled laser, and increase its pulse energy, and stretch its light The optical fiber gain stretcher is used to receive the second coupled laser, increase its pulse energy, and broaden its spectrum to form a second broad spectrum laser; two output couplers are respectively a first output coupler 5 and a second output coupler 12, the first output coupler 5 is used to receive the first broad spectrum laser, and output part of the first broad spectrum laser according to a set ratio, the second output coupler 12 is used to receive the second broad spectrum laser, and output part of the second broad spectrum laser according to a set ratio; and two optical isolators are respectively a first optical isolator and a second optical isolator, the first optical isolator is used to receive the broad spectrum laser passing through the first output coupler and ensure its unidirectional passage to form a first unidirectional broad spectrum laser, and at the same time isolate the residual light transmitted in the reverse direction, the second optical isolator is used to receive the broad spectrum laser passing through the first output coupler and ensure its unidirectional passage to form a second unidirectional broad spectrum laser, and at the same time isolate the residual light transmitted in the reverse direction.

[0047] Among them, the input end of the first spectral filter is connected to the first optical isolator, which is used to receive the first unidirectional broadband laser and allow the part that meets the set wavelength to pass through, forming the first narrow spectrum laser; the input end of the second spectral filter is connected to the second optical isolator, which is used to receive the second unidirectional broadband laser and allow the part that meets the set wavelength to pass through, forming the second narrow spectrum laser, thereby forming a self-starting Mamyshev fiber laser oscillation circuit.

[0048] In the embodiments of the present disclosure, Figure 1 As shown, the first optical fiber gain stretcher includes a first gain optical fiber 3 and a first passive optical fiber 4. The first gain optical fiber 3 is used to amplify the power of the first coupled laser, and at the same time initially broaden its spectrum and transmit it to the first passive optical fiber 4 for further broadening to form the first wide-spectrum laser.

[0049] In the embodiments of the present disclosure, Figure 1 As shown, the second optical fiber gain stretcher includes a second gain optical fiber 10 and a second passive optical fiber 11. The second gain optical fiber 10 is used to amplify the power of the second coupled laser, and at the same time initially broaden its spectrum and transmit it to the second passive optical fiber 11 for further broadening to form the second wide-spectrum laser.

[0050] Furthermore, the center wavelength of the gain spectrum of the first gain optical fiber matches the working wavelength of the second spectrum filter to obtain a higher gain.

[0051] Furthermore, the center wavelength of the gain spectrum of the second gain optical fiber matches the working wavelength of the first spectrum filter to obtain a higher gain.

[0052] Furthermore, the first passive optical fiber can utilize its own nonlinearity to cause the spectrum to undergo frequency conversion to generate new spectrum components, while trying to concentrate the new spectrum components in the filtering band of the first spectrum filter.

[0053] Furthermore, the second passive optical fiber can utilize its own nonlinearity to cause the spectrum to undergo frequency conversion to generate new spectrum components, while trying to concentrate the new spectrum components in the filtering band of the second spectrum filter.

[0054] In the embodiments of the present disclosure, the first passive optical fiber or the second passive optical fiber includes ordinary single-mode optical fiber, dispersion-compensating optical fiber, highly nonlinear optical fiber and photonic crystal optical fiber.

[0055] Specifically, Figure 1As shown, in the self-starting Mamyshev fiber oscillator device based on spectral modulation, the first pump laser output by the first pump source 1 is coupled through the first wavelength division multiplexer 2 to form a first coupled laser and enter the first gain fiber 3. Under the influence of the reabsorption effect of the first gain fiber, the central wavelength of the gain spectrum will drift toward the long-wave direction as the length of the gain fiber increases. Therefore, a first gain fiber 3 of a suitable length is selected to match the central wavelength of its gain spectrum with the working wavelength of the second spectrum filter 14 to obtain a higher gain. The amplified pulse laser passes through the first passive fiber 4. The function of the first passive fiber 4 is to use its own nonlinearity to make the spectrum undergo frequency conversion to generate new spectral components. Parameters such as the dispersion coefficient, nonlinear coefficient and length of the first passive fiber 4 will affect the result of frequency conversion. By selecting appropriate parameters of the first passive fiber 4, the spectral intensity distribution after frequency conversion can be modulated so that it has a strong energy distribution in the working band of the spectrum filter 7. The narrow spectrum pulse laser after passing through the first spectrum filter 7 passes through the second wavelength division multiplexer 9, the second gain fiber 10 and the second passive fiber 11 in sequence. The pump light output by the second pump source 8 is coupled by the second wavelength division multiplexer 9 to form the second coupled light and enter the second gain fiber 10. The second gain fiber 10 of appropriate length is selected so that the central wavelength of its gain spectrum matches the central wavelength of the first spectrum filter 7. The parameters of the passive fiber 11 are selected appropriately so that the broadened spectrum has a strong energy distribution in the working band of the second spectrum filter 14. The first output coupler 5 and the second output coupler 12 are used to derive part of the laser in the device as output, and can also be used to monitor the parameters of the pulse in the device. The optical isolators 6 and 13 can ensure the unidirectional operation of the laser in the device, while preventing the residual light transmitted in the reverse direction from affecting the operation of the laser.

[0056] So far, the embodiments of the present disclosure have been described in detail in conjunction with the accompanying drawings. It should be noted that the implementation methods not shown or described in the drawings or the body of the specification are all forms known to ordinary technicians in the relevant technical field and are not described in detail. In addition, the above definitions of each element and method are not limited to the various specific structures, shapes or methods mentioned in the embodiments, and ordinary technicians in the field can simply change or replace them.

[0057] According to the above description, those skilled in the art should have a clear understanding of the self-starting Mamyshev fiber oscillator device based on spectral modulation disclosed in the present invention.

[0058] In summary, the present disclosure provides a self-starting Mamyshev fiber oscillator device based on spectral modulation, which can effectively improve the self-starting performance of the Mamyshev oscillator, will not increase the complexity of the laser structure, is conducive to integrated design, and maintains a relatively high output energy. It realizes the adjustment of the gain spectrum and the spectrum generated by frequency conversion in the Mamyshev oscillator device to match the filter working band, reduces the locking threshold of the Mamyshev oscillator, and realizes the self-starting operation of the Mamyshev oscillator.

[0059] It should also be noted that the directional terms mentioned in the embodiments, such as "upper", "lower", "front", "back", "left", "right", etc., are only reference directions of the drawings and are not intended to limit the scope of protection of the present disclosure. Throughout the drawings, the same elements are represented by the same or similar reference numerals. Conventional structures or configurations will be omitted when they may cause confusion in the understanding of the present disclosure.

[0060] Moreover, the shapes and sizes of the components in the figures do not reflect the real size and proportion, but only illustrate the contents of the embodiments of the present disclosure. In addition, in the claims, any reference symbols between brackets shall not be constructed as limiting the claims.

[0061] Unless otherwise indicated, the numerical parameters in this specification and the appended claims are approximate values ​​and can vary according to the desired properties obtained through the content of the present disclosure. Specifically, all numbers used in the specification and claims to express the content of the composition, reaction conditions, etc., should be understood to be modified by the term "about" in all cases. In general, the meaning of the expression is to include a variation of ±10% in some embodiments, ±5% in some embodiments, ±1% in some embodiments, and ±0.5% in some embodiments by a specific number.

[0062] Furthermore, the word "comprising" does not exclude the presence of elements or steps not listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements.

[0063] The ordinal numbers used in the specification and claims, such as "first", "second", "third", etc., to modify the corresponding elements, do not themselves mean that the elements have any ordinal numbers, nor do they represent the order of one element and another element, or the order in the manufacturing method. The use of these ordinal numbers is only used to clearly distinguish a component with a certain name from another component with the same name.

[0064] In addition, unless the steps are specifically described or must occur in sequence, the order of the above steps is not limited to the above list, and can be changed or rearranged according to the required design. And the above embodiments can be mixed and matched with each other or with other embodiments based on design and reliability considerations, that is, the technical features in different embodiments can be freely combined to form more embodiments.

[0065] Those skilled in the art will appreciate that the modules in the devices in the embodiments may be adaptively changed and set in one or more devices different from the embodiments. The modules or units or components in the embodiments may be combined into one module or unit or component, and in addition they may be divided into multiple submodules or subunits or subcomponents. All features disclosed in this specification (including the accompanying claims, abstracts and drawings) and all processes or units of any method or device disclosed in this manner may be combined in any combination, except that at least some of such features and / or processes or units are mutually exclusive. Unless otherwise expressly stated, each feature disclosed in this specification (including the accompanying claims, abstracts and drawings) may be replaced by an alternative feature that provides the same, equivalent or similar purpose. Furthermore, in a unit claim that lists several devices, several of these devices may be embodied by the same hardware item.

[0066] Similarly, it should be understood that in order to streamline the present disclosure and aid in understanding one or more of the various disclosed aspects, in the above description of the exemplary embodiments of the present disclosure, the various features of the present disclosure are sometimes grouped together into a single embodiment, figure, or description thereof. However, this disclosed method should not be interpreted as reflecting the following intention: the claimed disclosure requires more features than the features explicitly recited in each claim. More specifically, as reflected in the claims below, the disclosed aspects are less than all the features of the single embodiment disclosed above. Therefore, the claims that follow the specific embodiment are hereby expressly incorporated into the specific embodiment, with each claim itself serving as a separate embodiment of the present disclosure.

[0067] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present disclosure. It should be understood that the above description is only a specific embodiment of the present disclosure and is not intended to limit the present disclosure. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present disclosure should be included in the protection scope of the present disclosure.

Claims

1. A self-starting Mamyshev fiber laser oscillator based on spectral modulation, comprising: Two spectral filters, namely a first spectral filter and a second spectral filter, wherein the first spectral filter is used to output a first narrow spectrum laser, and the second spectral filter is used to output a second narrow spectrum laser; Two pump sources, namely a first pump source and a second pump source, are used to output a first pump laser and a second pump laser respectively; Two wavelength division multiplexers, namely a first wavelength division multiplexer and a second wavelength division multiplexer, wherein the first wavelength division multiplexer is used to receive the first pump laser and the second narrow spectrum laser, and couple them to form a first coupled laser, and the second wavelength division multiplexer is used to receive the second pump laser and the first narrow spectrum laser, and couple them to form a second coupled laser; Two optical fiber gain stretchers, namely a first optical fiber gain stretcher and a second optical fiber gain stretcher, wherein the first optical fiber stretcher is used to receive the first coupled laser, increase its pulse energy, and stretch its spectrum to form a first wide-spectrum laser, and the second optical fiber gain stretcher is used to receive the second coupled laser, increase its pulse energy, and stretch its spectrum to form a second wide-spectrum laser; two output couplers, namely a first output coupler and a second output coupler, wherein the first output coupler is used to receive the first broad-spectrum laser and output a portion of the first broad-spectrum laser according to a set ratio, and the second output coupler is used to receive the second broad-spectrum laser and output a portion of the second broad-spectrum laser according to a set ratio; and two optical isolators, namely a first optical isolator and a second optical isolator, the first optical isolator is used to receive the broad-spectrum laser light passing through the first output coupler and ensure that it passes through in one direction, thereby forming a first unidirectional broad-spectrum laser light, while isolating the residual light transmitted in the reverse direction, and the second optical isolator is used to receive the broad-spectrum laser light passing through the first output coupler and ensure that it passes through in one direction, thereby forming a second unidirectional broad-spectrum laser light, while isolating the residual light transmitted in the reverse direction; The input end of the first spectrum filter is connected to the first optical isolator, and is used to receive the first unidirectional wide-spectrum laser and pass the portion that matches the set wavelength to form the first narrow-spectrum laser. The input end of the second spectrum filter is connected to the second optical isolator, and is used to receive the second unidirectional wide-spectrum laser and pass the portion that matches the set wavelength to form the second narrow-spectrum laser, thereby forming a self-starting Mamyshev fiber laser oscillation circuit. The first optical fiber gain stretcher comprises a first gain optical fiber and a first passive optical fiber, wherein the first gain optical fiber is used to amplify the power of the first coupled laser, and at the same time initially broaden its spectrum and transmit it to the first passive optical fiber for further broadening to form the first wide-spectrum laser, and the first passive optical fiber utilizes its own nonlinearity to cause the spectrum to undergo frequency conversion to generate new spectrum components, and at the same time, the new spectrum components are concentrated in the filtering band of the first spectrum filter; The second optical fiber gain stretcher comprises a second gain optical fiber and a second passive optical fiber, wherein the second gain optical fiber is used to amplify the power of the second coupled laser, and at the same time initially broaden its spectrum and transmit it to the second passive optical fiber for further broadening to form a second broadened laser; The center wavelength of the gain spectrum of the first gain optical fiber matches the working wavelength of the second spectrum filter to obtain a higher gain; The center wavelength of the gain spectrum of the second gain optical fiber matches the working wavelength of the first spectrum filter to obtain a higher gain.

2. The self-starting Mamyshev fiber laser oscillator according to claim 1, wherein: The second passive optical fiber utilizes its own nonlinearity to cause the spectrum to undergo frequency conversion to generate new spectrum components, while trying to concentrate the new spectrum components in the filtering band of the second spectrum filter.

3. The self-starting Mamyshev fiber laser oscillator according to claim 1, wherein: The first passive optical fiber or the second passive optical fiber includes common single-mode optical fiber, dispersion-compensating optical fiber, highly nonlinear optical fiber and photonic crystal optical fiber.

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