Parallel distribution feedback assembly for laser linewidth compression and regulation and control method thereof

Abstract

The invention provides a parallel distributed feedback assembly for laser linewidth compression and a regulation and control method thereof, and the assembly comprises a distributed feedback structure which feeds back a scattering signal to a laser main cavity after receiving a laser signal provided by the laser main cavity, so as to carry out the linewidth compression of the laser signal. By increasing the transverse area of the distributed feedback structure and shortening the axial length of the distributed feedback structure, the number of effective photons fed back to a laser main cavity and used for line width compression by the distributed feedback structure at the same time is increased, and therefore the laser line width compression effect is improved. According to the invention, the phase interference matching probability during line width compression is increased, and the line width compression effect of the laser signal and the stability of the laser signal finally output by the laser are improved.

Description

Technical Field

[0001] The present invention belongs to the field of lasers, and in particular relates to a parallel distributed feedback component for laser linewidth compression and a control method thereof. Background Art

[0002] Narrow-linewidth lasers with high spectral purity and low phase noise play a vital role in various applications, including high-speed coherent optical communications and precision measurement. External cavity feedback is an effective method for achieving laser linewidth compression, primarily encompassing fixed external cavity optical feedback and distributed feedback. Fixed external cavity feedback requires strict phase matching with the laser's main cavity; otherwise, mode hopping can easily occur. Distributed feedback, on the other hand, feeds the Rayleigh backscattered signal accumulated in the feedback waveguide back into the laser's main cavity, achieving deep compression of the laser linewidth by continuously modifying the main cavity signal's phase. However, because the Rayleigh scattered optical signal is extremely weak, a long scattering medium, such as hundreds of meters of ordinary single-mode fiber, is typically required to accumulate a sufficiently strong feedback signal. Furthermore, Rayleigh scattering is highly sensitive to fluctuations in configuration parameters and the surrounding environment. Scattering media located farther away are more susceptible to environmental changes, which can affect the stability of narrow-linewidth lasers based on distributed feedback. Summary of the Invention

[0003] The present invention provides a parallel distributed feedback component for laser linewidth compression and a control method thereof, so as to solve the problem that when lasers currently use distributed feedback technology to achieve linewidth compression, the feedback medium is long, easily affected by the external environment, and the linewidth compression effect and laser output stability are poor.

[0004] According to a first aspect of the present invention, a parallel distributed feedback component for laser linewidth compression is provided, comprising a distributed feedback structure, wherein after receiving a laser signal provided by a laser main cavity, the distributed feedback structure feeds back a scattered signal to the laser main cavity to perform linewidth compression on the laser signal;

[0005] By increasing the lateral area of ​​the distributed feedback structure and shortening the axial length of the distributed feedback structure, the number of effective photons simultaneously fed back to the laser main cavity by the distributed feedback structure for linewidth compression is increased, thereby improving the laser linewidth compression effect.

[0006] In an optional implementation, the distributed feedback structure includes a plurality of distributed feedback waveguides, the laser main cavity is connected to the plurality of distributed feedback waveguides respectively via a first coupler, and after receiving the laser signal provided by the laser main cavity, the plurality of distributed feedback waveguides simultaneously feed back the scattered signal to the laser main cavity, thereby increasing the number of effective photons simultaneously fed back to the laser main cavity by the distributed feedback structure for linewidth compression;

[0007] Compared with the linewidth compression effect when the laser main cavity is connected to a single distributed feedback waveguide, the linewidth compression effect is better when the laser main cavity is connected to the multiple distributed feedback waveguides respectively and the total length of the multiple distributed feedback waveguides is equal to the length of the single distributed feedback waveguide.

[0008] In another optional implementation, the multiple distributed feedback waveguides have the same length, and the scattered signal is a Rayleigh scattered signal.

[0009] In another optional implementation, the multiple distributed feedback waveguides can further improve the scattering coefficient through micro-nano processing.

[0010] In another optional implementation, the ends of the multiple distributed feedback waveguides are all knotted.

[0011] In another optional implementation, an optical switch is further included, and there is at least one first coupler. The distributed feedback structure is a modular waveguide, and each modular waveguide is provided with multiple distributed feedback waveguides. The input end of the optical switch is connected to the laser main cavity, and the output end is respectively connected to the first end of each first coupler. Each first coupler is provided with multiple second ends, and each second end of each first coupler is used to connect to a corresponding modular waveguide.

[0012] For laser signals of different linewidths provided by the laser main cavity, when the laser main cavity is connected to each modular waveguide and any combination of the modular waveguides, the laser signal can be compressed to a corresponding linewidth. Based on the laser signal linewidth provided by the laser main cavity and the target linewidth to which it is required to be compressed, the modular waveguides to be connected to the laser main cavity are determined. Then, based on the determined number of modular waveguides and the number of second ends on each first coupler, corresponding first couplers are selected to be connected to the optical switch, and the total number of second ends on the selected first couplers is greater than or equal to the determined number of modular waveguides.

[0013] According to a second aspect of the present invention, a control method for the parallel distributed feedback component for laser linewidth compression is also provided. Assuming that the unit length of a single distributed feedback waveguide is L0, the maximum allowable length of the single distributed feedback waveguide is M*L0, where M is an integer greater than 1 and a set value, and L0 is an arbitrary value greater than 0; for laser signals of different linewidths provided by a laser main cavity, a processor locally stores a first linewidth to which the laser signal can be compressed when the laser main cavity is connected to the single distributed feedback waveguide and the length of the single distributed feedback waveguide is 1 to M times the unit length L0;

[0014] For laser signals of different linewidths provided by the laser main cavity, the processor further locally stores combinations of the number and average length of the multiple distributed feedback waveguides when the total length of the multiple distributed feedback waveguides is 1 to M times the unit length L0, and a second linewidth to which the laser signal can be compressed when the laser main cavity is connected to the multiple distributed feedback waveguides in each combination;

[0015] For each combination where the total length of the multiple distributed feedback waveguides is i times the unit length L0, when the laser main cavity is connected to the multiple distributed feedback waveguides in the combination, the second linewidth to which the laser signal can be compressed is smaller than the first linewidth W to which the laser signal can be compressed when the laser main cavity is connected to a single distributed feedback waveguide with a length of i*L0. i , and is greater than the first line width W to which the laser signal can be compressed when the laser main cavity is connected to a single distributed feedback waveguide with a length of (i+1)*L0 i+1 The value range of i is [1, M]. For each combination when the total length of the multiple distributed feedback waveguides is 1 to M times the unit length L0, each combination corresponds to a modular waveguide.

[0016] After receiving the laser signal linewidth provided by the laser main cavity and the target linewidth to be compressed, the processor determines the number and average length of the plurality of distributed feedback waveguides according to the following steps:

[0017] Step S210: Determine corresponding first linewidths based on the laser signal linewidth provided by the laser main cavity; compare the target linewidth with the first linewidths in sequence to obtain a first linewidth that is closest to the target linewidth and larger than the target linewidth; determine the length k*L0 of a single distributed feedback waveguide corresponding to the obtained first linewidth; the value range of k is [1, M], and it is an arbitrary integer;

[0018] Step S220: When the total length of the plurality of distributed feedback waveguides is determined to be k*L0, a combination of the number and average length of the plurality of distributed feedback waveguides is determined, and a second linewidth corresponding to the determined combination is found;

[0019] Step S230: Compare the target linewidth with the found second linewidths to obtain the second linewidth closest to the target linewidth, and use the number and average length of the obtained second linewidths corresponding to the combination as the number and average length of the multiple distributed feedback waveguides.

[0020] In an optional implementation, assuming that the maximum number of distributed feedback waveguides that the first coupler allows to connect is N, for the laser signal provided by the laser cavity, the number and average length combination of the multiple distributed feedback waveguides corresponding to the total length of the multiple distributed feedback waveguides is determined according to the following steps when the total length of the multiple distributed feedback waveguides is 1 to M times the unit length L0:

[0021] Step S110: for the laser signal provided by the laser main cavity, determine the first line width W to which the laser signal can be compressed when the laser main cavity is connected to a single distributed feedback waveguide with a length of (i+1)*L0. i+1 ; The value range of i is [1,M], and its initial value is 1, M is the set value;

[0022] Step S120: Determine that when the number of distributed feedback waveguides is j and the average length of each distributed feedback waveguide is i*L0 / j, the laser signal can be compressed to a line width W when the laser main cavity is connected to the j distributed feedback waveguides. i,j , determine the line width W i,j Is it greater than the line width W? i+1 If so, the number j and the average length i*L0 / j are combined as the total length of the distributed feedback waveguides i*L0, and the number and average length of the distributed feedback waveguides are combined as the line width W i,j As the second line width under this combination, j++ is set and the execution returns to step S120. Otherwise, j is set to the initial value, i++, and the execution returns to step S110, where the value range of j is [2,N] and its initial value is 2.

[0023] In another optional implementation, the processor further locally stores the second power of the scattered signal fed back by the multiple distributed feedback waveguides in each combination when the laser main cavity is connected to the multiple distributed feedback waveguides, and the first power of the scattered signal required to compress the laser signal to the target linewidth;

[0024] After the processor outputs the number and average length of the multiple distributed feedback waveguides through a display screen, it also displays second powers corresponding to the multiple distributed feedback waveguides and a first power of a scattered signal required to compress the laser signal to the target linewidth, so that a user can adjust the length of a corresponding distributed feedback waveguide among the multiple distributed feedback waveguides according to the first power and the second power until the power displayed on a power meter is equal to the first power. The power meter is used to measure the power of the scattered signals fed back by the multiple distributed feedback waveguides.

[0025] The beneficial effects of the present invention are:

[0026] 1. By increasing the lateral area of ​​the distributed feedback structure and shortening its axial length, the present invention can increase the number of effective photons fed back to the laser main cavity by the distributed feedback structure for linewidth compression. This increases the probability of phase interference matching during linewidth compression and improves the linewidth compression effect of the laser signal provided by the laser main cavity. In addition, since the axial length of the distributed feedback structure is shortened, it is less affected by the external environment, and the influence of nonlinear effects on linewidth compression is reduced, so the laser signal ultimately output by the laser is more stable.

[0027] 2. The present invention ties knots at the ends of multiple distributed feedback waveguides, which can avoid strong feedback at the fiber end face and affect the laser line width;

[0028] 3. The present invention modularizes multiple distributed feedback waveguides to reduce the volume of the distributed feedback component and realize the integration of the distributed feedback component. By pre-obtaining the modular waveguide to be connected to the laser main cavity to compress the laser signal from the initial linewidth to the corresponding linewidth, and then selecting the modular waveguide connected to the laser main cavity based on the laser signal linewidth provided by the laser main cavity and the target linewidth to be compressed, the corresponding modular waveguide can be quickly matched, thereby quickly achieving the linewidth compression effect.

[0029] 4. The present invention adds a processor to locally store in the processor a first linewidth to which the laser signal can be compressed when the laser main cavity is connected to the single distributed feedback waveguide and the length of the single distributed feedback waveguide is 1 to M times the unit length L0, a corresponding number and average length combination of the multiple distributed feedback waveguides when the laser main cavity is connected to the multiple distributed feedback waveguides and the total length of the multiple distributed feedback waveguides is 1 to M times the unit length L0, and a second linewidth to which the laser signal can be compressed when the laser main cavity is connected to the multiple distributed feedback waveguides in each combination, and for each combination when the total length of the multiple distributed feedback waveguides is i times the unit length L0, the second linewidth to which the laser signal can be compressed when the laser main cavity is connected to the multiple distributed feedback waveguides in the combination is smaller than the first linewidth W to which the laser signal can be compressed when the laser main cavity is connected to a single distributed feedback waveguide with a length of i*L0. i , and is greater than the second linewidth W to which the laser signal can be compressed when the laser main cavity is connected to a single distributed feedback waveguide with a length of (i+1)*L0 i+1This can make a single modular waveguide and any combination of modular waveguides more diverse, thereby making the compressible linewidth more diverse. Users can more quickly select a matching modular waveguide and quickly compress the laser signal to the target linewidth. In addition, when the above modular waveguide cannot meet the compression requirements, the lengths of multiple distributed feedback waveguides in the modular waveguide can be adjusted according to the power displayed by the power meter. This can further improve the diversification of the compression effect, thereby quickly achieving non-standardized linewidth compression. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 1 is a schematic structural diagram of an embodiment of a parallel distributed feedback component for laser linewidth compression according to the present invention;

[0031] Figure 2 This is a diagram of the linewidth compression effect when the laser main cavity is connected to a single distributed feedback waveguide;

[0032] Figure 3 It is the linewidth compression effect when the laser main cavity is connected to multiple distributed feedback waveguides, and the total length of the multiple distributed feedback waveguides is equal to the length of a single distributed feedback waveguide;

[0033] Figure 4 This is a comparison of the linewidth compression effect when the laser main cavity is connected to a single distributed feedback waveguide and multiple distributed feedback waveguides;

[0034] Figure 5 1 is a schematic structural diagram of another embodiment of a parallel distributed feedback component for laser linewidth compression according to the present invention;

[0035] Figure 6 This is a schematic structural diagram of another embodiment of a parallel distributed feedback component for laser linewidth compression according to the present invention;

[0036] Figure 7 This is a flow chart of an embodiment of the parallel distributed feedback component control method of the present invention;

[0037] Figure 8 It is a schematic structural diagram of an embodiment of the narrow linewidth laser of the present invention. DETAILED DESCRIPTION

[0038] In order to enable those skilled in the art to better understand the technical solutions in the embodiments of the present invention and to make the above-mentioned purposes, features and advantages of the embodiments of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention are further described in detail below with reference to the accompanying drawings.

[0039] In the description of the present invention, unless otherwise specified and limited, it should be noted that the term "connection" should be understood in a broad sense. For example, it can be a mechanical connection or an electrical connection, or it can be the internal connection between two elements. It can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meaning of the above terms can be understood according to the specific circumstances.

[0040] See also Figure 1 , is a schematic diagram of the structure of an embodiment of a parallel distributed feedback component for laser linewidth compression according to the present invention. The parallel distributed feedback component may include a distributed feedback structure 2. After receiving the laser signal provided by the laser main cavity 1, the distributed feedback structure 2 feeds back the scattered signal to the laser main cavity 1 to perform linewidth compression on the laser signal. By increasing the lateral area of ​​the distributed feedback structure 2 and shortening the axial length of the distributed feedback structure 2, the number of effective photons simultaneously fed back to the laser main cavity 1 by the distributed feedback structure 2 for linewidth compression is increased, thereby improving the laser linewidth compression effect.

[0041] The distributed feedback structure 2 may include multiple distributed feedback waveguides (the multiple distributed feedback waveguides may be distributed feedback optical fibers), and the laser main cavity 1 may be connected to the multiple distributed feedback waveguides respectively through a first coupler 3. After receiving the laser signal provided by the laser main cavity 1, the multiple distributed feedback waveguides simultaneously feed back the scattered signal (such as the Rayleigh scattering signal) to the laser main cavity, thereby increasing the number of effective photons that the distributed feedback structure 2 simultaneously feeds back to the laser main cavity 1 for linewidth compression. Figures 2 to 4 As shown, compared to the linewidth compression effect when the laser main cavity 1 is connected to a single distributed feedback waveguide, the linewidth compression effect is better when the laser main cavity 1 is connected to multiple distributed feedback waveguides separately, and the total length of the multiple distributed feedback waveguides is equal to the length of the single distributed feedback waveguide. The multiple distributed feedback waveguides can have the same length, and the distributed feedback waveguides can be arranged in parallel (for example, arranged in parallel).

[0042] In this embodiment, multiple spatially parallel distributed feedback waveguides simultaneously feed their scattered signals back into the laser's main cavity. The distributed feedback phase is inherently random, but the interference of the backscattered signals from the multiple distributed feedback waveguides redistributes the discrete phases, thereby narrowing the linewidth of the laser that achieves linewidth compression based on random interference. This invention can be applied to on-chip waveguides, which can be hybridized or heterogeneously integrated with the laser chip. The laser can be a diode narrow-linewidth laser. Furthermore, when a laser is connected to multiple distributed feedback waveguides, to avoid strong feedback at the fiber end face and the impact on the laser linewidth, the ends of the multiple distributed feedback waveguides can be knotted. For example, two cascaded coil knots with a radius of less than 2 mm can be tied at the end of each distributed feedback waveguide. The multiple distributed feedback waveguides are all high-scattering fibers with a scattering coefficient higher than that of single-mode fibers. The scattering coefficient of the multiple distributed feedback waveguides can be further increased through micro-nanofabrication. The multiple distributed feedback waveguides can include one or more of HSF fibers, UHNA3 fibers, and THORLABS fibers. The plurality of distributed feedback waveguides may be three.

[0043] As can be seen from the above embodiments, the present invention increases the lateral area of ​​the distributed feedback structure and shortens the axial length of the distributed feedback structure, thereby increasing the number of effective photons fed back to the laser main cavity by the distributed feedback structure for linewidth compression. This increases the probability of phase interference matching during linewidth compression and improves the linewidth compression effect of the laser signal provided by the laser main cavity. In addition, since the axial length of the distributed feedback structure is shortened, it is less affected by the external environment, and the influence of nonlinear effects on linewidth compression is reduced, so the laser signal ultimately output by the laser is more stable.

[0044] Also, see Figure 5 , is a structural diagram of another embodiment of the parallel distributed feedback component for laser linewidth compression of the present invention. Figure 5 and Figure 1The embodiment shown differs in that it may further include an optical switch 7, there is at least one first coupler 3, and the distributed feedback structure may be a modular waveguide, each modular waveguide being provided with multiple distributed feedback waveguides. The input end of the optical switch 7 is connected to the laser main cavity 1, and the output end is respectively connected to the first end of each first coupler 3. Each first coupler 3 is provided with multiple second ends, and each second end of each first coupler 3 is used to connect to a corresponding modular waveguide. For laser signals of different linewidths provided by the laser main cavity 1, when the laser main cavity 1 is connected to each modular waveguide, or any combination of modular waveguides, the laser signal can be compressed to the corresponding linewidth. Based on the laser signal linewidth provided by the laser main cavity 1 and the target linewidth to be compressed, the modular waveguide to be connected to the laser main cavity is determined. Then, based on the determined number of modular waveguides and the number of second ends of each first coupler 3, the corresponding first coupler is selected to be connected to the optical switch 7, with the total number of second ends of the selected first couplers 3 being greater than or equal to the determined number of modular waveguides.

[0045] The present invention may further include a controller for controlling the operation of the optical switch 7. For laser signals of varying linewidths provided by the laser main cavity 1, the controller locally stores information on the linewidths to which the laser signal can be compressed when the laser main cavity 1 is connected to each modular waveguide, as well as any combination of modular waveguides. Upon receiving the laser signal linewidth provided by the laser main cavity 1 and the target linewidth to which the laser signal is to be compressed, the controller first locates the modular waveguide to be connected to the laser main cavity 1 and displays the identification information of the located modular waveguide on a display screen. The controller then controls the operation of the optical switch 7 to connect to the corresponding first coupler 3. Thereafter, the user connects the corresponding modular waveguide to the corresponding first coupler 3 based on the displayed identification information. The controller may determine the first coupler 3 to be connected to the optical switch based on the number of located modular waveguides and the number of second ends on the first coupler 3, such that the number of second ends on the determined first coupler 3 is greater than or equal to the number of located modular waveguides.

[0046] The present invention modularizes multiple distributed feedback waveguides to reduce the volume of the distributed feedback component and realize the integration of the distributed feedback component. By pre-acquiring the modular waveguide to be connected to the laser main cavity to compress the laser signal from the initial linewidth to the corresponding linewidth, and then selecting the modular waveguide connected to the laser main cavity based on the laser signal linewidth provided by the laser main cavity and the target linewidth to be compressed, the corresponding modular waveguide can be quickly matched, thereby quickly achieving the linewidth compression effect.

[0047] As can be seen from the above embodiments, the present invention increases the lateral area of ​​the distributed feedback structure and shortens the axial length of the distributed feedback structure, thereby increasing the number of effective photons fed back to the laser main cavity by the distributed feedback structure for linewidth compression. This increases the probability of phase interference matching during linewidth compression and improves the linewidth compression effect of the laser signal provided by the laser main cavity. In addition, since the axial length of the distributed feedback structure is shortened, it is less affected by the external environment, and the influence of nonlinear effects on linewidth compression is reduced, so the laser signal ultimately output by the laser is more stable.

[0048] In order to test the linewidth compression effect of the laser signal, Figure 6 As shown, the distributed feedback component may further include an MZI interferometer 4 connected to the first coupler 3, and the MZI interferometer 4 is used to detect the line width of the laser finally output by the laser; wherein the MZI interferometer 4 may include a second coupler 41, a delay fiber 42, an acousto-optic modulator 43, a third coupler 44, a photodetector 45 and a spectrum analyzer 46, wherein the corresponding port of the first coupler 3 is connected to the input end of the second coupler 41, the first output end of the second coupler 41 is connected to the first input end of the third coupler 44 through the delay fiber 42, and the second output end is connected to the third coupler 44 through the acousto-optic modulator 43. The second input end and the output end of the third coupler 44 are connected to the spectrum analyzer 46 via the photodetector 45. The first coupler 3 transmits the linewidth-compressed laser signal to the second coupler 41. The second coupler 41 splits the laser signal into two paths: one path is delayed by the delay fiber 42 and transmitted to the third coupler 44, and the other path is frequency-shifted by the acousto-optic modulator 43 and transmitted to the third coupler 44. The two signals interfere at the third coupler 44, generating an interference signal. The photodetector 45 converts the interference signal into an electrical signal, and the spectrum analyzer 46 detects the linewidth of the laser light ultimately output by the laser based on the electrical signal. An isolator 5 is also provided between the second coupler 41 and the first coupler 3.

[0049] The parallel distributed feedback component may also include a power meter connected to the first coupler, which monitors the power of the scattered signals fed back by the multiple distributed feedback waveguides. It should be noted that the present invention may include only an MZI interferometer, only a power meter, or both. The present invention is provided with an MZI interferometer and / or a power meter to detect the final linewidth of the laser signal output by the laser, so as to determine whether the compression effect of the laser signal meets the standard based on the detected laser linewidth.

[0050] In addition, although the above embodiment modularizes multiple distributed feedback waveguides, pre-acquires the modular waveguides to be connected to the laser main cavity to compress the laser signal from the initial linewidth to the corresponding linewidth, and then selects the modular waveguide connected to the laser main cavity based on the laser signal linewidth provided by the laser main cavity and the target linewidth to be compressed, so that the compression effect can be quickly achieved, how to set the number and length of the multiple distributed feedback waveguides on the modular waveguide to make the single modular waveguide and any combination of modular waveguides more diverse, thereby making the compressible linewidth more diverse, still remains a problem that needs to be solved.

[0051] To this end, the present invention further provides a control method for the above-mentioned parallel distributed feedback component for laser linewidth compression, wherein the unit length of a single distributed feedback waveguide is L0, the maximum allowable length of the single distributed feedback waveguide is M*L0, M is an integer greater than 1 and a set value, and L0 is an arbitrary value greater than 0; for laser signals of different linewidths provided by a laser main cavity, a processor locally stores a first linewidth to which the laser signal can be compressed when the laser main cavity is connected to the single distributed feedback waveguide and the length of the single distributed feedback waveguide is 1 to M times the unit length L0;

[0052] For laser signals of different linewidths provided by the laser main cavity, the processor further locally stores combinations of the number and average length of the multiple distributed feedback waveguides when the total length of the multiple distributed feedback waveguides is 1 to M times the unit length L0, and a second linewidth to which the laser signal can be compressed when the laser main cavity is connected to the multiple distributed feedback waveguides in each combination;

[0053] For each combination where the total length of the multiple distributed feedback waveguides is i times the unit length L0, when the laser main cavity is connected to the multiple distributed feedback waveguides in the combination, the second linewidth to which the laser signal can be compressed is smaller than the first linewidth W to which the laser signal can be compressed when the laser main cavity is connected to a single distributed feedback waveguide with a length of i*L0. i , and is greater than the first line width W to which the laser signal can be compressed when the laser main cavity is connected to a single distributed feedback waveguide with a length of (i+1)*L0 i+1 The value range of i is [1, M]. For each combination when the total length of the multiple distributed feedback waveguides is 1 to M times the unit length L0, each combination can be corresponded to a modular waveguide.

[0054] After receiving the laser signal linewidth provided by the laser main cavity and the target linewidth to be compressed, the processor determines the number and average length of the plurality of distributed feedback waveguides according to the following steps:

[0055] Step S210: Determine corresponding first linewidths based on the laser signal linewidth provided by the laser main cavity; compare the target linewidth with the first linewidths in sequence to obtain a first linewidth that is closest to the target linewidth and larger than the target linewidth; determine the length k*L0 of a single distributed feedback waveguide corresponding to the obtained first linewidth; the value range of k is [1, M], and it is an arbitrary integer;

[0056] Step S220: When the total length of the plurality of distributed feedback waveguides is determined to be k*L0, a combination of the number and average length of the plurality of distributed feedback waveguides is determined, and a second linewidth corresponding to the determined combination is found;

[0057] Step S230: Compare the target linewidth with the found second linewidths to obtain the second linewidth closest to the target linewidth, and use the number and average length of the obtained second linewidths corresponding to the combination as the number and average length of the multiple distributed feedback waveguides.

[0058] Assuming that the maximum number of distributed feedback waveguides that the first coupler allows to be connected is N, for the laser signal provided by the laser cavity, the number and average length combination of the multiple distributed feedback waveguides corresponding to the total length of the multiple distributed feedback waveguides is determined according to the following steps when the total length of the multiple distributed feedback waveguides is 1 to M times the unit length L0:

[0059] Step S110: for the laser signal provided by the laser main cavity, determine the first line width W to which the laser signal can be compressed when the laser main cavity is connected to a single distributed feedback waveguide with a length of (i+1)*L0. i+1 ; The value range of i is [1,M], and its initial value is 1, M is the set value;

[0060] Step S120: Determine that when the number of distributed feedback waveguides is j and the average length of each distributed feedback waveguide is i*L0 / j, the laser signal can be compressed to a line width W when the laser main cavity is connected to the j distributed feedback waveguides. i,j , determine the line width W i,j Is it greater than the line width W? i+1 If so, the number j and the average length i*L0 / j are combined as the total length of the distributed feedback waveguides i*L0, and the number and average length of the distributed feedback waveguides are combined as the line width W i,j As the second line width under this combination, j++ is set and the execution returns to step S120. Otherwise, j is set to the initial value, i++, and the execution returns to step S110, where the value range of j is [2,N] and its initial value is 2.

[0061] In addition, the processor also locally stores the second power of the scattered signal fed back by the multiple distributed feedback waveguides in each combination when the laser main cavity is connected to the multiple distributed feedback waveguides, and the first power of the scattered signal required to compress the laser signal to the target linewidth;

[0062] After the processor outputs the number and average length of the multiple distributed feedback waveguides through a display screen, it also displays second powers corresponding to the multiple distributed feedback waveguides and a first power of a scattered signal required to compress the laser signal to the target linewidth, so that a user can adjust the length of a corresponding distributed feedback waveguide among the multiple distributed feedback waveguides according to the first power and the second power until the power displayed on a power meter is equal to the first power. The power meter is used to measure the power of the scattered signals fed back by the multiple distributed feedback waveguides.

[0063] The present invention adds a processor to locally store in the processor a first linewidth to which the laser signal can be compressed when the laser main cavity is connected to the single distributed feedback waveguide and the length of the single distributed feedback waveguide is 1 to M times the unit length L0; a corresponding number and average length combination of the multiple distributed feedback waveguides when the laser main cavity is connected to the multiple distributed feedback waveguides and the total length of the multiple distributed feedback waveguides is 1 to M times the unit length L0; and a second linewidth to which the laser signal can be compressed when the laser main cavity is connected to the multiple distributed feedback waveguides in each combination. Moreover, for each combination when the total length of the multiple distributed feedback waveguides is i times the unit length L0, the second linewidth to which the laser signal can be compressed when the laser main cavity is connected to the multiple distributed feedback waveguides in the combination is smaller than the first linewidth W to which the laser signal can be compressed when the laser main cavity is connected to a single distributed feedback waveguide with a length of i*L0. i , and is greater than the second linewidth W to which the laser signal can be compressed when the laser main cavity is connected to a single distributed feedback waveguide with a length of (i+1)*L0 i+1 This can make a single modular waveguide and any combination of modular waveguides more diverse, thereby making the compressible linewidth more diverse. Users can more quickly select a matching modular waveguide and quickly compress the laser signal to the target linewidth. In addition, when the above modular waveguide cannot meet the compression requirements, the lengths of multiple distributed feedback waveguides in the modular waveguide can be adjusted according to the power displayed by the power meter. This can further improve the diversification of the compression effect, thereby quickly achieving non-standardized linewidth compression.

[0064] In addition, the present invention also provides a narrow linewidth laser, which may include the above-mentioned parallel distributed feedback component and a laser main cavity connected to the parallel distributed feedback component, wherein the laser main cavity provides a laser signal to the parallel distributed feedback component, and the parallel distributed feedback component feeds back the scattered signal to the laser main cavity to compress the linewidth of the laser signal.

[0065] As can be seen from the above embodiments, the present invention increases the lateral area of ​​the distributed feedback structure and shortens the axial length of the distributed feedback structure, thereby increasing the number of effective photons fed back to the laser main cavity by the distributed feedback structure and used for linewidth compression, thereby increasing the phase interference matching probability during linewidth compression and improving the linewidth compression effect of the laser signal; in addition, since the axial length of the distributed feedback structure is shortened, it is less affected by the external environment, and the influence of nonlinear effects on linewidth compression is reduced, so the laser signal ultimately output by the laser is more stable; the laser of the present invention can achieve narrow linewidth compression.

[0066] Other embodiments of the present invention will readily occur to those skilled in the art after considering the specification and practicing the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the present invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The description and examples are to be considered as exemplary only, with the true scope and spirit of the invention being indicated by the following claims.

[0067] It will be appreciated that the present invention is not limited to the precise construction that has been described above and shown in the accompanying drawings, and that various modifications and variations can be made without departing from its scope, which is governed solely by the appended claims.

Claims

1. A parallel distributed feedback component for laser linewidth compression, It is characterized in that The method comprises a distributed feedback structure, wherein after receiving a laser signal provided by a laser main cavity, the distributed feedback structure feeds back a scattered signal to the laser main cavity to perform line width compression on the laser signal; The number of effective photons simultaneously fed back to the laser main cavity by the distributed feedback structure and used for line width compression is increased by increasing the lateral area of ​​the distributed feedback structure and shortening the axial length of the distributed feedback structure, thereby improving the laser line width compression effect.

2. The parallel distributed feedback assembly for laser linewidth compression according to claim 1, It is characterized in that The distributed feedback structure includes a plurality of distributed feedback waveguides, the laser main cavity is connected to the plurality of distributed feedback waveguides respectively through a first coupler, and after receiving the laser signal provided by the laser main cavity, the plurality of distributed feedback waveguides simultaneously feed back the scattered signals to the laser main cavity, so as to increase the number of effective photons simultaneously fed back to the laser main cavity by the distributed feedback structure for line width compression; Compared with the linewidth compression effect when the laser main cavity is connected to a single distributed feedback waveguide, the linewidth compression effect is better when the laser main cavity is connected to the multiple distributed feedback waveguides respectively and the total length of the multiple distributed feedback waveguides is equal to the length of the single distributed feedback waveguide.

3. The parallel distributed feedback component for laser line width compression according to claim 1 or 2, It is characterized in that The multiple distributed feedback waveguides have the same length, and the scattered signal is a Rayleigh scattered signal.

4. The parallel distributed feedback assembly for laser linewidth compression according to claim 1, It is characterized in that The multiple distributed feedback waveguides can further improve the scattering coefficient through micro-nano processing.

5. The parallel distributed feedback assembly for laser linewidth compression according to claim 2, It is characterized in that The ends of the plurality of distributed feedback waveguides are all knotted.

6. The parallel distributed feedback assembly for laser line width compression according to claim 2, It is characterized in that It also includes an optical switch, and the first coupler is at least one, the distributed feedback structure is a modular waveguide, and each modular waveguide is provided with a plurality of distributed feedback waveguides; the input end of the optical switch is connected to the main cavity of the laser, and the output end is respectively connected to the first end of each first coupler, each first coupler is provided with a plurality of second ends, and each second end of each first coupler is used to connect to the corresponding modular waveguide; For laser signals with different line widths provided by the laser main cavity, when the laser main cavity is respectively connected to various modular waveguides and any combination of various modular waveguides, the laser signal can be compressed to the corresponding line width; according to the laser signal line width provided by the laser main cavity and the target line width to be compressed, the modular waveguide to be connected to the laser main cavity is determined, and then according to the determined number of modular waveguides and the number of second ends on each first coupler, the corresponding first coupler is selected to be connected to the optical switch, and the total number of the second ends on the selected first couplers is greater than or equal to the determined number of modular waveguides.

7. A control method for a parallel distributed feedback component according to any one of claims 1 to 6, It is characterized in that Assuming that the unit length of a single distributed feedback waveguide is L0, the maximum length of a single distributed feedback waveguide allowed is M*L0, M is an integer greater than 1 and is a set value, and L0 is an arbitrary value greater than 0; for laser signals of different line widths provided by a laser main cavity, the processor locally stores the first line width to which the laser signal can be compressed when the laser main cavity is connected to the single distributed feedback waveguide and the length of the single distributed feedback waveguide is 1 to M times the unit length L0; For laser signals of different line widths provided by the laser main cavity, the processor also locally stores the number and average length combination of the multiple distributed feedback waveguides when the total length of the multiple distributed feedback waveguides is 1 to M times the unit length L0, and the second line width to which the laser signal can be compressed when the laser main cavity is connected to the multiple distributed feedback waveguides in each combination; For each combination when the total length of the multiple distributed feedback waveguides is i times the unit length L0, when the laser main cavity is connected to the multiple distributed feedback waveguides in the combination, the second line width to which the laser signal can be compressed is smaller than the first line width W to which the laser signal can be compressed when the laser main cavity is connected to a single distributed feedback waveguide with a length of i*L0. i , and is greater than the first line width W to which the laser signal can be compressed when the laser main cavity is connected to a single distributed feedback waveguide with a length of (i+1)*L0 i+1 ; The value range of i is [1,M]; for each combination when the total length of the multiple distributed feedback waveguides is 1 to M times the unit length L0, each combination corresponds to a modular waveguide; After receiving the laser signal line width provided by the laser main cavity and the target line width to be compressed, the processor determines the number and average length of the plurality of distributed feedback waveguides according to the following steps: Step S210, determining the corresponding first line widths according to the laser signal line width provided by the laser main cavity; comparing the target line width with the first line widths in turn to obtain a first line width that is closest to the target line width and larger than the target line width; determining the length k*L0 of a single distributed feedback waveguide corresponding to the obtained first line width; the value range of k is [1,M], and it is an arbitrary integer; Step S220, when it is determined that the total length of the plurality of distributed feedback waveguides is k*L0, the number and average length combination of the plurality of distributed feedback waveguides corresponding to the plurality of distributed feedback waveguides, and finding out a second line width corresponding to the determined combination; Step S230, comparing the target line width with the found second line widths respectively to obtain the second line width closest to the target line width, and using the number and average length of the obtained second line width corresponding to the combination as the number and average length of the multiple distributed feedback waveguides.

8. The control method according to claim 7, It is characterized in that Assuming that the maximum number of distributed feedback waveguides that the first coupler allows to be connected is N, for the laser signal provided by the laser cavity, the number and average length combination of the multiple distributed feedback waveguides corresponding to the total length of the multiple distributed feedback waveguides when they are 1 to M times the unit length L0 are determined according to the following steps: Step S110: for the laser signal provided by the laser main cavity, determine the first line width W to which the laser signal can be compressed when the laser main cavity is connected to a single distributed feedback waveguide with a length of (i+1)*L0. i+1 ; The value range of i is [1,M], and its initial value is 1, and M is the set value; Step S120: Determine that when the number of the plurality of distributed feedback waveguides is j, the average length of each distributed feedback waveguide is i*L0 / j, and the laser signal can be compressed to a line width W when the laser main cavity is connected to the j distributed feedback waveguides. i,j , determine the line width W i,j Is it greater than the line width W? i+1 If so, then the number j and the average length i*L0 / j are combined as the number and average length corresponding to the plurality of distributed feedback waveguides when the total length of the plurality of distributed feedback waveguides is i*L0, and the line width W is i,j As the second line width under this combination, j++ is set and the execution returns to step S120. Otherwise, j is set to the initial value, i++, and the execution returns to step S110, where the value range of j is [2,N] and its initial value is 2.

9. The control method according to claim 7, It is characterized in that The processor also locally stores the second power of the scattered signal fed back by the multiple distributed feedback waveguides when the laser main cavity is connected to the multiple distributed feedback waveguides in each combination, and the first power of the scattered signal required for the laser signal to be compressed to the target line width; After the processor outputs the number and average length of the multiple distributed feedback waveguides through a display screen, the processor also displays the second power corresponding to the multiple distributed feedback waveguides and the first power of the scattered signal required for the laser signal to be compressed to the target line width, so that the user can adjust the length of the corresponding distributed feedback waveguide in the multiple distributed feedback waveguides according to the first power and the second power until the power displayed on the power meter is equal to the first power. The power meter is used to measure the power of the scattered signal fed back by the multiple distributed feedback waveguides.

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