Multi-wavelength laser modulation system and modulation method

Abstract

The invention provides a multi-wavelength laser modulation system and method, and the system comprises a light source which is used for providing coaxial multi-wavelength incident light; the acousto-optic modulator is used for receiving the coaxial multi-wavelength incident light, the incident angle of the coaxial multi-wavelength incident light is a fixed incident angle, and the coaxial multi-wavelength incident light is modulated by a multi-frequency radio-frequency signal in the acousto-optic modulator to form coaxial multi-wavelength diffracted light; the radio frequency driver is used for providing a multi-frequency radio frequency signal for the acousto-optic modulator, the multi-frequency radio frequency signal is determined based on the fixed incident angle and the wavelength of the coaxial multi-wavelength incident light, and the frequency of the multi-frequency radio frequency signal corresponds to the wavelength of the coaxial multi-wavelength incident light. Coaxial multi-wavelength incident light is input into the acousto-optic modulator at a fixed incident angle, and is modulated by multi-frequency radio-frequency signals in one-to-one correspondence with the wavelengths of the coaxial multi-wavelength incident light to form coaxial multi-wavelength diffracted light output, so that coaxial input and output of multi-wavelength laser are realized.

Description

Technical Field

[0001] The present invention relates to the technical field of acousto-optic modulation, and in particular to a modulation system and a modulation method of a multi-wavelength laser. Background Art

[0002] Acousto-optic modulation is an external modulation technology. The acousto-optic device that controls the intensity change of the laser beam is usually called an acousto-optic modulator. The acousto-optic modulator is composed of an acousto-optic medium and a piezoelectric transducer. When a certain carrier frequency of the driving source drives the transducer, the transducer generates ultrasonic waves of the same frequency and transmits them to the acousto-optic medium, forming an acoustic change in the refractive index in the medium. When the light beam passes through the medium, an interaction occurs and the propagation direction of the light is changed, which is called diffraction.

[0003] At present, the acousto-optic modulation method is to adjust lasers of different wavelengths to different Bragg angles at a fixed RF frequency, and the angles of the diffracted light are also different. If lasers of different wavelengths are incident at a fixed angle, it will lead to a wavelength-momentum mismatch that does not meet the Bragg angle, the diffraction efficiency will be reduced, and the diffracted light will be output at different angles, and coaxiality cannot be achieved. Summary of the invention

[0004] Based on this, it is necessary to provide a multi-wavelength laser modulation system and modulation method to address the problems in the above-mentioned background technology, which can realize the coaxial input and output of diffracted light.

[0005] To achieve the above objectives and other related objectives, one aspect of the present application provides a modulation system for a multi-wavelength laser, comprising:

[0006] A light source, used for providing coaxial multi-wavelength incident light;

[0007] an acousto-optic modulator, for receiving coaxial multi-wavelength incident light, the incident angle of the coaxial multi-wavelength incident light is a fixed incident angle, and the coaxial multi-wavelength incident light is modulated by a multi-frequency radio frequency signal in the acousto-optic modulator to form a coaxial multi-wavelength diffracted light;

[0008] The RF driver is used to provide a multi-frequency RF signal to the AOM, wherein the multi-frequency RF signal is determined based on a fixed incident angle and the wavelength of the coaxial multi-wavelength incident light, and the frequency of the multi-frequency RF signal corresponds to the wavelength of the coaxial multi-wavelength incident light.

[0009] In one embodiment, the modulation system of the coaxial multi-wavelength laser further includes: a fiber coupling structure for coupling the coaxial multi-wavelength diffracted light, and the fiber coupling structure is arranged along the axial direction of the coaxial multi-wavelength diffracted light.

[0010] In one embodiment, the RF driver provides the multi-frequency RF signal to the AOM, including: the RF driver provides mixed RF signals of different frequencies to the AOM at the same time, and the AOM receives mixed RF signals of different frequencies from the RF driver at the same time.

[0011] In one embodiment, the RF driver provides the AOM with a multi-frequency RF signal, including: the RF driver provides the AOM with RF signals of different frequencies at different times, and the AOM receives a single-frequency RF signal from the RF driver at the same time.

[0012] In one embodiment, the multi-frequency RF signal includes at least a first frequency RF signal and a second frequency RF signal, and the RF driver AOM simultaneously provides a mixed signal of the first frequency RF signal and the second frequency RF signal, or the RF driver provides the first frequency RF signal to the AOM at a first time and provides the second frequency RF signal to the AOM at a second time, and the RF driver alternately provides the first frequency RF signal and the second frequency RF signal.

[0013] In one embodiment, the light source provides the coaxial multi-wavelength incident light to the AOM, including: the light source provides mixed incident light of different wavelengths to the AOM at the same time, and the AOM receives mixed incident light of different wavelengths from the AOM at the same time.

[0014] In one embodiment, the light source provides coaxial multi-wavelength incident light to the AOM, including: the light source provides incident light of different wavelengths to the AOM at different times, and the AOM receives incident light of a single wavelength from the light source at the same time.

[0015] In one embodiment, the light source includes a plurality of independent light sources, and the plurality of independent light sources respectively provide incident light of different wavelengths to form mixed incident light of different wavelengths.

[0016] In one embodiment, the light source includes a tunable light source, which provides incident light of different wavelengths at different times, and which provides incident light of a single wavelength at the same time.

[0017] In one embodiment, the difference between different wavelengths in the mixed incident light of different wavelengths is greater than a preset value.

[0018] In one embodiment, the coaxial multi-wavelength incident light includes at least a first wavelength incident light and a second wavelength incident light, the multi-frequency radio frequency signal includes at least a first frequency radio frequency signal and a second frequency radio frequency signal, the first wavelength incident light corresponds to the first frequency radio frequency signal, the second wavelength incident light corresponds to the second frequency radio frequency signal, and the product of the first wavelength and the first frequency is associated with the product of the second wavelength and the second frequency.

[0019] In one embodiment, the modulation system of the coaxial multi-wavelength laser further includes: a clock generator for controlling the clocks of the light source and the RF driver so that the incident light emitted by the light source and the RF signal emitted by the RF driver are synchronized in the acousto-optic modulator.

[0020] Another aspect of the present invention provides a modulation method for a multi-wavelength laser, comprising the following steps:

[0021] Obtaining coaxial multi-wavelength incident light;

[0022] determining a multi-frequency radio frequency signal based on a fixed incident angle of the coaxial multi-wavelength incident light and a wavelength of the coaxial multi-wavelength incident light, wherein a frequency of the multi-frequency radio frequency signal corresponds to the wavelength of the coaxial multi-wavelength incident light;

[0023] The coaxial multi-wavelength incident light is modulated by a multi-frequency radio frequency signal to form a coaxial multi-wavelength diffracted light.

[0024] According to the modulation system and modulation method of the multi-wavelength laser provided by the present invention, the coaxial multi-wavelength incident light is input into the acousto-optic modulator at a fixed incident angle, and the RF driver provides the acousto-optic modulator with a multi-frequency RF signal corresponding to the wavelength of the coaxial multi-wavelength incident light, so that the diffracted light of the coaxial multi-wavelength incident light can be output at the same diffraction angle to form coaxial multi-wavelength diffracted light, thereby realizing the coaxial input and output of the multi-wavelength laser. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to better describe and illustrate the embodiments and / or examples of those applications disclosed herein, reference may be made to one or more drawings. The additional details or examples used to describe the drawings should not be considered as limiting the scope of any of the disclosed applications, the embodiments and / or examples currently described, and the best modes of these applications currently understood.

[0026] Figure 1 It is a schematic diagram of multi-wavelength laser modulation in the prior art;

[0027] Figure 2 is a schematic block diagram of a modulation system for a multi-wavelength laser provided in an embodiment;

[0028] Figure 3 A schematic diagram of the structure of a modulation system for a multi-wavelength laser provided in an embodiment;

[0029] Figure 4 It is a schematic structural diagram of another multi-wavelength laser modulation system provided in an embodiment;

[0030] Figure 5 is a schematic diagram of a clock signal, a radio frequency frequency and a wavelength provided in one embodiment;

[0031] Figure 6 A schematic diagram showing the relationship between wavelength and ultrasonic power utilization rate provided in an embodiment;

[0032] Figure 7 A schematic diagram of the relationship between wavelength and radio frequency provided in an embodiment;

[0033] Figure 8 Flow chart of a modulation method of a multi-wavelength laser provided in one embodiment.

[0034] Description of reference numerals:

[0035] 100. Light source; 101. First light source; 102. Second light source; 103. Third light source; 104. First optical device; 105. Second optical device; 106. Third optical device; 200. Acousto-optic modulator; 300. RF driver; 400. Fiber coupling structure; 500. Clock generator. DETAILED DESCRIPTION

[0036] In order to facilitate understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present application are given in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0038] The purpose of the terms used herein is only to describe specific embodiments and is not intended to be limiting of the present application. When used herein, the singular forms "one", "an" and "said / the" are also intended to include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "consisting of" and / or "comprising", when used in this specification, determine the presence of the features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or groups. When used herein, the term "and / or" includes any and all combinations of the relevant listed items.

[0039] It should be noted that the illustrations provided in this embodiment only illustrate the basic concept of the present application in a schematic manner. Although the illustrations only show components related to the present application and are not drawn according to the number, shape and size of components in actual implementation, the type, quantity and proportion of each component in actual implementation may be changed arbitrarily, and the component layout type may also be more complicated.

[0040] At present, the acousto-optic modulation method is to adjust the lasers of different wavelengths λ to different Bragg angles θ at a fixed RF frequency f in order to ensure the diffraction efficiency of lasers of different wavelengths λ. B Incident. Bragg angle θ B The formula is , where λ represents the wavelength of the incident light, f represents the radio frequency, and v represents the crystal acoustic wave velocity. Figure 1 As shown, for a laser with a wavelength of λ1, when the RF frequency is fixed at f, its Bragg angle is θ B1 , the diffracted light formed is λ1-1; for a laser with a wavelength of λ2, when the RF frequency is fixed at f, its Bragg angle is θ B2 , the diffracted light formed is λ2-1. The diffraction angles of the diffracted light λ1-1 and the diffracted light λ2-1 are different, and coaxiality cannot be achieved.

[0041] Furthermore, if lasers with different wavelengths λ are incident at a fixed angle θ under a fixed RF frequency f, not only will the diffraction efficiency of wavelengths that do not meet the Bragg angle be reduced due to momentum mismatch, but the diffracted light will still be output at different angles, making it impossible to achieve coaxiality.

[0042] In view of the above problems, the present invention provides a modulation system for multi-wavelength lasers, such as Figure 2 As shown, including:

[0043] The light source 100 is used to provide coaxial multi-wavelength incident light;

[0044] The acousto-optic modulator 200 is used to receive coaxial multi-wavelength incident light, the incident angle of the coaxial multi-wavelength incident light is a fixed incident angle, and the coaxial multi-wavelength incident light is modulated by a multi-frequency radio frequency signal in the acousto-optic modulator to form a coaxial multi-wavelength diffracted light;

[0045] The RF driver 300 is used to provide a multi-frequency RF signal to the AOM 200, wherein the multi-frequency RF signal is determined based on a fixed incident angle and the wavelength of the coaxial multi-wavelength incident light, and the frequency of the multi-frequency RF signal corresponds to the wavelength of the coaxial multi-wavelength incident light.

[0046] In one embodiment, the light source 100 provides mixed incident light of different wavelengths to the AOM 200 at the same time, and the AOM 200 receives mixed incident light of different wavelengths from the AOM 200 at the same time. Specifically, the light source 100 includes a plurality of independent light sources, and the plurality of independent light sources respectively provide incident light of different wavelengths to form mixed incident light of different wavelengths. The difference between the wavelengths of the incident light of different wavelengths is greater than a preset value.

[0047] Reference Figure 3 As shown, in one embodiment, the light source 100 includes a first light source 101, a second light source 102, and a third light source 103. The first light source 101 emits a first wavelength incident light λ1, the second light source 102 emits a second wavelength incident light λ2, and the third light source 103 emits a third wavelength incident light λ3. In order to reduce the influence of stray diffracted light of different wavelengths, the difference between each wavelength in the incident light of different wavelengths is usually greater than a preset value, and the preset value is usually greater than 50nm, including but not limited to 50nm, 100nm, 150nm, etc. The light source 100 also includes a first optical device 104, a second optical device 105, and a third optical device 106. The first optical device 104 is arranged corresponding to the first light source 101 to change the optical path of the first wavelength incident light λ1; the second optical device 105 is arranged corresponding to the second light source 102 to change the optical path of the second wavelength incident light λ2, and the second optical device 105 is also used to transmit the first wavelength incident light λ1 so that the second wavelength incident light λ2 is coaxial with the first wavelength incident light λ1; the third optical device 106 is arranged corresponding to the third light source 103 to change the optical path of the third wavelength incident light λ3, and the third optical device 106 is also used to transmit the first wavelength incident light λ1 and the second wavelength incident light λ2 so that the third wavelength incident light λ3 is coaxial with the second wavelength incident light λ2 and the first wavelength incident light λ1. After the optical paths of the first wavelength incident light λ1, the second wavelength incident light λ2 and the third wavelength incident light λ3 are adjusted by the first optical device 104, the second optical device 105 and the third optical device 106, coaxial multi-wavelength incident light is a mixed incident light of different wavelengths.

[0048] In one embodiment, the light source 100 provides incident light of different wavelengths to the AOM 200 at different times, and the AOM 200 receives incident light of a single wavelength from the light source 100 at the same time. Specifically, the light source 100 includes a tunable light source, and the tunable light source provides incident light of a single wavelength at the same time, so that the coaxial multi-wavelength incident light is provided by making the tunable light source provide incident light of different wavelengths at different times.

[0049] Reference Figure 4As shown, in one embodiment, the light source 100 includes a tunable light source, and the tunable light source can only emit a single wavelength of laser light as incident light at the same time. Specifically, the tunable light source provides a first wavelength incident light λ1 at a first time, provides a second wavelength incident light λ2 at a second time, and provides a third wavelength incident light λ3 at a third time, and the first wavelength incident light λ1, the second wavelength incident light λ2, and the third wavelength incident light λ3 are coaxial. The time interval of the tunable light source is set, and the tunable light source outputs the first wavelength incident light λ1, the second wavelength incident light λ2, and the third wavelength incident light λ3 at a certain time interval, and provides the first wavelength incident light λ1, the second wavelength incident light λ2, and the third wavelength incident light λ3 as coaxial multi-wavelength incident light to the acousto-optic modulator 200.

[0050] In one embodiment, the acousto-optic modulator 200 may be a broadband acousto-optic modulator. The acousto-optic medium material in the acousto-optic modulator 200 includes but is not limited to tellurium dioxide, quartz, fused quartz, etc. The acoustic wave mode of the acousto-optic modulator 200 selects a longitudinal wave mode.

[0051] In one embodiment, the RF driver 300 provides mixed RF signals of different frequencies to the AOM 200 at the same time, and the AOM 200 receives mixed RF signals of different frequencies from the RF driver 300 at the same time. Specifically, the multi-frequency RF signal includes at least a first frequency RF signal and a second frequency RF signal, and the RF driver 300 provides a mixed signal of the first frequency RF signal and the second frequency RF signal to the AOM 200 at the same time.

[0052] Reference Figure 3 As shown, in one embodiment, the RF driver 300 simultaneously transmits a first frequency RF signal f1, a second frequency RF signal f2 and a third frequency RF signal f3, wherein the first frequency RF signal f1 corresponds to the first wavelength incident light λ1, the second frequency RF signal f2 corresponds to the second wavelength incident light λ2, and the third frequency RF signal f3 corresponds to the third wavelength incident light λ3, and provides a mixed signal of the first frequency RF signal f1, the second frequency RF signal f2 and the third frequency RF signal f3 to the AOM 200.

[0053] In one embodiment, the RF driver 300 provides RF signals of different frequencies to the AOM 200 at different times, and the AOM 200 receives a single-frequency RF signal from the RF driver 300 at the same time. Specifically, the multi-frequency RF signal includes at least a first-frequency RF signal and a second-frequency RF signal. The RF driver 300 provides the first-frequency RF signal to the AOM 200 at a first time, and provides the second-frequency RF signal to the AOM 200 at a second time. The RF driver provides the first-frequency RF signal and the second-frequency RF signal alternately at a certain period and duration time interval.

[0054] Reference Figure 3 or Figure 4 As shown, in one embodiment, the RF driver 300 can only send out RF signals of the same frequency at the same time, so the RF driver 300 provides RF signals of different frequencies at different times to provide multi-frequency RF signals. Specifically, the RF driver 300 provides a first frequency RF signal f1 at a first time, a second frequency RF signal f2 at a second time, and a third frequency RF signal f3 at a third time, wherein the first frequency RF signal f1 corresponds to the first wavelength incident light λ1, the second frequency RF signal f2 corresponds to the second wavelength incident light λ2, and the third frequency RF signal f3 corresponds to the third wavelength incident light λ3. The period and time interval of the RF driver 300 are set, and the RF driver 300 outputs the first frequency RF signal f1, the second frequency RF signal f2 and the third frequency RF signal f3 at a certain period and continuous time interval, and provides the first frequency RF signal f1, the second frequency RF signal f2 and the third frequency RF signal f3 as multi-frequency RF signals to the acousto-optic modulator 200. In addition, a filter circuit is also provided in the RF driver 300 to eliminate clutter signals.

[0055] In one embodiment, the modulation system of the coaxial multi-wavelength laser may further include a fiber coupling structure 400, which is used to couple the coaxial multi-wavelength diffracted light, and the fiber coupling structure 400 is arranged along the axial direction of the coaxial multi-wavelength diffracted light.

[0056] In one embodiment, for the coaxial multi-wavelength incident light, the incident angle of the coaxial multi-wavelength incident light to the acousto-optic modulator 200 is a fixed incident angle θ, and after being modulated by the multi-frequency radio frequency signal, the diffraction angle θ' of the diffracted light formed is the same, so the coaxial multi-wavelength incident light is modulated by the multi-frequency radio frequency signal to form a coaxial multi-wavelength diffracted light. When the optical fiber coupling structure 400 is arranged along the axial direction of the coaxial multi-wavelength diffracted light (that is, arranged along the diffraction angle of the coaxial multi-wavelength diffracted light), refer to Figure 3 As shown, the coaxial multi-wavelength diffracted light can be received by the fiber coupling structure 400.

[0057] In one embodiment, referring to Figure 3 As shown, for the mixed incident light formed by the first wavelength incident light λ1, the second wavelength incident light λ2 and the third wavelength incident light λ3, when the RF driver 300 simultaneously transmits the first frequency RF signal f1, the second frequency RF signal f2 and the third frequency RF signal f3, the first wavelength incident light λ1 is modulated by the first frequency RF signal f1 to form a first diffracted light with a diffraction angle of θ', and the diffracted light formed by the first wavelength incident light λ1 modulated by the second frequency RF signal f2 or the third frequency RF signal f3 is stray light, the diffraction efficiency of the stray light is low, and it is not coaxial with the first diffracted light, and cannot be received by the optical fiber coupling structure 400. Similarly, the second wavelength incident light λ2 is modulated by the second frequency RF signal f2 to form a second diffracted light with a diffraction angle of θ', and the diffracted light formed by the second wavelength incident light λ2 is modulated by the first frequency RF signal f1 or the third frequency RF signal f3 is stray light, the diffraction efficiency of the stray light is low, and it is not coaxial with the second diffracted light, and cannot be received by the optical fiber coupling structure 400. The third wavelength incident light λ3 is modulated by the third frequency radio frequency signal f3 to form a third diffracted light with a diffraction angle of θ'. The diffracted light formed by the third wavelength incident light λ3 being modulated by the first frequency radio frequency signal f1 or the second frequency radio frequency signal f2 is stray light. The diffraction efficiency of the stray light is low, and the stray light is not coaxial with the third diffracted light, and cannot be received by the optical fiber coupling structure 400. Further, the diffraction angles of the first diffracted light, the second diffracted light, and the third diffracted light are the same, that is, the first diffracted light, the second diffracted light, and the third diffracted light are coaxial, and the coaxial multi-wavelength diffracted light formed by the first diffracted light, the second diffracted light, and the third diffracted light is received by the optical fiber coupling structure 400.

[0058] In one embodiment, referring to Figure 3As shown, for the mixed incident light formed by the first wavelength incident light λ1, the second wavelength incident light λ2 and the third wavelength incident light λ3, when the RF driver 300 sequentially transmits the first frequency RF signal f1, the second frequency RF signal f2 and the third frequency RF signal f3, the first wavelength incident light λ1 is modulated by the first frequency RF signal f1 to form a first diffracted light with a diffraction angle of θ', and the diffracted light formed by the second wavelength incident light λ2 and the third wavelength incident light λ3 are modulated by the first frequency RF signal f1 is stray light, the diffraction efficiency of the stray light is low, and it is not coaxial with the first diffracted light, and cannot be received by the optical fiber coupling structure 400. Similarly, the second wavelength incident light λ2 is modulated by the second frequency RF signal f2 to form a second diffracted light with a diffraction angle of θ', and the diffracted light formed by the first wavelength incident light λ1 and the third wavelength incident light λ3 are modulated by the second frequency RF signal f2 is stray light, the diffraction efficiency of the stray light is low, and it is not coaxial with the second diffracted light, and cannot be received by the optical fiber coupling structure 400. The third wavelength incident light λ3 is modulated by the third frequency radio frequency signal f3 to form a third diffracted light with a diffraction angle of θ'. The diffracted light formed by the first wavelength incident light λ1 and the second wavelength incident light λ2 is modulated by the third frequency radio frequency signal f3 is stray light. The diffraction efficiency of the stray light is low, and the stray light is not coaxial with the third diffracted light, and cannot be received by the fiber coupling structure 400. Further, the diffraction angles of the first diffracted light, the second diffracted light and the third diffracted light are the same, that is, the first diffracted light, the second diffracted light and the third diffracted light are coaxial, and the coaxial multi-wavelength diffracted light formed by the first diffracted light, the second diffracted light and the third diffracted light is received by the fiber coupling structure 400.

[0059] In one embodiment, the modulation system of the coaxial multi-wavelength laser further includes a clock generator 500, which is used to control the clocks of the light source 100 and the RF driver 300, so that the incident light emitted by the light source 100 and the RF signal emitted by the RF driver 300 are synchronized in the acousto-optic modulator 200.

[0060] In one embodiment, referring to Figure 4 As shown, the clock generator 500 transmits a clock signal and controls the delay of the tunable light source and the RF driver 300 respectively, so that the first wavelength incident light λ1 is synchronized with the first frequency RF signal f1 in the AOM 200, the first wavelength incident light λ1 is modulated by the first frequency RF signal f1, the second wavelength incident light λ2 is synchronized with the second frequency RF signal f2 in the AOM 200, the second wavelength incident light λ2 is modulated by the second frequency RF signal f2, the third wavelength incident light λ3 is synchronized with the third frequency RF signal f3 in the AOM 200, and the third wavelength incident light λ3 is modulated by the third frequency RF signal f3. By synchronizing incident light of different wavelengths with RF signals of corresponding frequencies in the AOM 200, stray light can be avoided and fast scanning modulation of multi-wavelength lasers can be achieved.

[0061] In one embodiment, referring to Figure 4 and Figure 5 As shown, in one clock cycle, the light source 100 sequentially emits a first wavelength incident light λ1, a second wavelength incident light λ2 and a third wavelength incident light λ3, and the RF driver 300 sequentially emits a first frequency RF signal f1, a second frequency RF signal f2 and a third frequency RF signal f3, the first wavelength incident light λ1 is modulated by the first frequency RF signal f1 to form a first diffracted light with a diffraction angle of θ', the second wavelength incident light λ2 is modulated by the second frequency RF signal f2 to form a second diffracted light with a diffraction angle of θ', the third wavelength incident light λ3 is modulated by the third frequency RF signal f3 to form a third diffracted light with a diffraction angle of θ', and the first diffracted light, the second diffracted light and the third diffracted light form a coaxial multi-wavelength diffracted light. Figure 5 As shown, the duration of the radio frequency signal of each frequency is slightly longer than the duration of the incident light of each wavelength, so as to ensure that the incident light of each wavelength can be diffracted.

[0062] In one embodiment, for the coaxial multi-wavelength incident light, the incident angle of the incident AOM 200 is a fixed incident angle θ, and the multi-frequency RF signal f is determined based on the fixed incident angle θ and the wavelength λ of the coaxial multi-wavelength incident light, and the frequency f of the multi-frequency RF signal corresponds one-to-one to the wavelength λ of the coaxial multi-wavelength incident light.

[0063] In one embodiment, the coaxial multi-wavelength incident light includes at least a first wavelength incident light λ1 and a second wavelength incident light λ2, the multi-frequency radio frequency signal includes at least a first frequency radio frequency signal f1 and a second frequency radio frequency signal f2, the first wavelength incident light λ1 corresponds to the first frequency radio frequency signal f1, the second wavelength incident light λ2 corresponds to the second frequency radio frequency signal f2, the product of the first wavelength and the first frequency is associated with the product of the second wavelength and the second frequency, for example, the product of the first wavelength and the first frequency is equal to the product of the second wavelength and the second frequency, that is, 2×v×θ=λ1×f1=λ2×f2.

[0064] In one embodiment, referring to Figure 6 As shown, taking the acousto-optic modulator 200 using a quartz acousto-optic modulator in the 400nm~650nm band as an example, when the incident angle When the wavelength of the first wavelength incident light λ1, the second wavelength incident light λ2 and the third wavelength incident light λ3 are 405nm, 532nm and 633nm respectively, the frequencies of the corresponding first frequency radio frequency signal f1, the second frequency radio frequency signal f2 and the third frequency radio frequency signal f3 are 148.5MHz, 113MHz and 95MHz respectively. For example, when the second frequency radio frequency signal f2 (113MHz) corresponding to the second wavelength incident light λ2 (532nm) is modulated, the diffracted light formed by the first wavelength incident light λ1 (405nm) and the third wavelength incident light λ3 (633nm) modulated by the second frequency radio frequency signal f2 (113MHz) is stray light, and the diffraction efficiency of the stray light is low, and the stray light is not coaxial with the second diffracted light.

[0065] In one embodiment, for an AOM, when the incident angle and the Bragg angle are consistent, the best diffraction efficiency can be achieved. When the incident angle and the Bragg angle deviate, the diffraction efficiency of the AOM decreases. The diffraction efficiency η is expressed as:

[0066]

[0067] Where M2 represents the quality factor of the acousto-optic material, Pa represents the ultrasonic power, and L and H represent the length and width of the transducer, respectively. The ultrasonic power Pa and the diffraction efficiency η are monotonically increasing nonlinear functions. Modulating the ultrasonic power Pa can achieve the purpose of modulating the diffraction efficiency η. The relationship between the ultrasonic power Pa and the ultrasonic power utilization rate BL can be expressed as:

[0068]

[0069]

[0070] in, represents the incident angle, represents the Bragg angle, L represents the transducer length, represents the acoustic wavelength, v represents the crystal acoustic wave velocity, and f represents the radio frequency. Therefore, the diffraction efficiency η can be characterized by the ultrasonic power utilization rate BL.

[0071] according to Figure 5It can be seen that when the incident angle is 0.3° and the frequency RF signal is the second frequency RF signal f2 (113MHz), the second wavelength incident light λ2 (532nm) has a small ultrasonic loss and a high ultrasonic power utilization rate BL, while the first wavelength incident light λ1 (405nm) and the third wavelength incident light λ3 (633nm) differ from the second wavelength incident light λ2 (532nm) by 10dB~12dB, indicating that the use of the second wavelength incident light λ 2 (532nm), the ultrasonic utilization rate BL of the first wavelength incident light λ1 (405nm) and the third wavelength incident light λ3 (633nm) is more than 10 times lower, which also means that when the frequency corresponding to the second wavelength incident light λ2 (532nm) is used, the diffraction efficiency η of the first wavelength incident light λ1 (405nm) and the third wavelength incident light λ3 (633nm) is much lower than the diffraction efficiency η of the second wavelength incident light λ2 (532nm). Figure 3 In the embodiment shown, the first wavelength incident light λ1 (405nm) and the third wavelength incident light λ3 (633nm) are modulated by the second frequency radio frequency signal f2 (113MHz) to form stray light, but the diffraction angles of the stray light and the coaxial multi-wavelength diffracted light are different (i.e., not coaxial), so Figure 3 The embodiment shown can use the fiber coupling structure 400 to receive only the coaxial multi-wavelength diffracted light. Figure 4 In the embodiment shown, the RF frequency changes synchronously with the wavelength, so no stray light is caused. Therefore, when the incident angle is fixed, the RF frequency can be changed to compensate for the angle difference caused by the wavelength, so that each wavelength has the same Bragg angle, and the ultrasonic power utilization rate at each wavelength is improved, that is, the diffraction efficiency of each wavelength is improved.

[0072] In addition, when the incident angle When the incident angles are different, the corresponding RF frequency also changes. For example, when the incident angles are fixed at 0.2°, 0.3°, and 0.4°, the corresponding relationship between the wavelength of the incident light and the RF frequency is as follows: Figure 7 In the 400nm~650nm band, when the fixed incident angle is 0.2°, the frequency range of the RF signal is between 62 MHz~100.2MHz; when the fixed incident angle is 0.3°, the frequency range of the RF signal is between 92.6 MHz~150.3MHz; when the fixed incident angle is 0.4°, the frequency range of the RF signal is between 123 MHz~200.4MHz.

[0073] According to the modulation system of the multi-wavelength laser provided by the present invention, the coaxial multi-wavelength incident light is input into the acousto-optic modulator at a fixed incident angle, and the RF driver provides the acousto-optic modulator with a multi-frequency RF signal corresponding to the wavelength of the coaxial multi-wavelength incident light, so that the diffracted light of the coaxial multi-wavelength incident light can be output at the same diffraction angle to form coaxial multi-wavelength diffracted light, thereby realizing the coaxial input and output of the multi-wavelength laser.

[0074] The present invention also provides a modulation method for multi-wavelength laser, such as Figure 8 As shown, the following steps are included:

[0075] Step S801: Acquire coaxial multi-wavelength incident light;

[0076] Step S802: determining a multi-frequency radio frequency signal based on a fixed incident angle of the coaxial multi-wavelength incident light and the wavelength of the coaxial multi-wavelength incident light, wherein the frequency of the multi-frequency radio frequency signal corresponds to the wavelength of the coaxial multi-wavelength incident light;

[0077] Step S803: The coaxial multi-wavelength incident light is modulated by a multi-frequency radio frequency signal to form a coaxial multi-wavelength diffracted light.

[0078] First, step S801 is performed to obtain coaxial multi-wavelength incident light. The coaxial multi-wavelength incident light includes mixed incident light of different wavelengths provided to the AOM 200 at the same time, such as Figure 3 The mixed incident light is formed by the first wavelength incident light λ1, the second wavelength incident light λ2 and the third wavelength incident light λ3. The coaxial multi-wavelength incident light also includes incident lights of different wavelengths provided to the AOM 200 at different times, such as Figure 4 As shown, the first wavelength incident light λ1 is provided at the first time, the second wavelength incident light λ2 is provided at the second time, and the third wavelength incident light λ3 is provided at the third time. The first wavelength incident light λ1, the second wavelength incident light λ2 and the third wavelength incident light λ3 are coaxial.

[0079] Then, step S802 is performed to determine a multi-frequency radio frequency signal based on the fixed incident angle of the coaxial multi-wavelength incident light and the wavelength of the coaxial multi-wavelength incident light, wherein the frequency of the multi-frequency radio frequency signal corresponds to the wavelength of the coaxial multi-wavelength incident light one by one. The multi-frequency radio frequency signal includes mixed radio frequency signals of different frequencies provided to the AOM 200 at the same time, such as Figure 3 The mixed RF signal formed by the first frequency RF signal f1, the second frequency RF signal f2 and the third frequency RF signal f3 shown in FIG. The multi-frequency signal also includes RF signals of different frequencies provided to the AOM 200 at different times, such as Figure 3 or Figure 4As shown, a first frequency RF signal f1 is provided at the first time, a second frequency RF signal f2 is provided at the second time, and a third frequency RF signal f3 is provided at the third time, wherein the first frequency RF signal f1 corresponds to the first wavelength incident light λ1, the second frequency RF signal f2 corresponds to the second wavelength incident light λ2, and the third frequency RF signal f3 corresponds to the third wavelength incident light λ3.

[0080] Then, step S803 is executed, and the coaxial multi-wavelength incident light is modulated by the multi-frequency radio frequency signal to form a coaxial multi-wavelength diffracted light. For the coaxial multi-wavelength incident light, the incident angle of the incident light to the acousto-optic modulator 200 is a fixed incident angle θ. After being modulated by the multi-frequency radio frequency signal, the diffraction angle θ' of the diffracted light formed is the same. Therefore, the coaxial multi-wavelength incident light is modulated by the multi-frequency radio frequency signal to form a coaxial multi-wavelength diffracted light. Figure 3 and Figure 4 The first wavelength incident light λ1 shown is modulated by the first frequency radio frequency signal f1 to form a first diffraction light with a diffraction angle of θ', the second wavelength incident light λ2 is modulated by the second frequency radio frequency signal f2 to form a second diffraction light with a diffraction angle of θ', and the third wavelength incident light λ3 is modulated by the third frequency radio frequency signal f3 to form a third diffraction light with a diffraction angle of θ'. The first diffraction light, the second diffraction light and the third diffraction light form coaxial multi-wavelength diffraction light. Figure 3 In the illustrated embodiment, the diffracted light formed by the incident light modulated by the non-corresponding RF signal is stray light. The diffraction efficiency of the stray light is low and it is not coaxial with the coaxial multi-wavelength diffracted light, and therefore cannot be received by the optical fiber coupling structure 400 .

[0081] According to the modulation method of multi-wavelength laser provided by the present invention, when coaxial multi-wavelength incident light is incident at a fixed incident angle, it is modulated by a multi-frequency radio frequency signal corresponding one-to-one to the wavelength of the coaxial multi-wavelength incident light, so that the diffracted light of the coaxial multi-wavelength incident light can be output at the same diffraction angle to form coaxial multi-wavelength diffracted light, thereby realizing the coaxial input and output of the multi-wavelength laser.

[0082] Please note that the above embodiments are for illustrative purposes only and are not intended to limit the present application.

[0083] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0084] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0085] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent application. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application.

Claims

1. A multi-wavelength laser modulation system, characterized in that: include: A light source, used for providing coaxial multi-wavelength incident light; an acousto-optic modulator, for receiving the coaxial multi-wavelength incident light, wherein the incident angle of the coaxial multi-wavelength incident light is a fixed incident angle, and the coaxial multi-wavelength incident light is modulated by a multi-frequency radio frequency signal in the acousto-optic modulator to form a coaxial multi-wavelength diffracted light; A radio frequency driver is used to provide the multi-frequency radio frequency signal to the acousto-optic modulator, wherein the multi-frequency radio frequency signal is determined based on the fixed incident angle and the wavelength of the coaxial multi-wavelength incident light, and the frequency of the multi-frequency radio frequency signal corresponds to the wavelength of the coaxial multi-wavelength incident light.

2. The multi-wavelength laser modulation system according to claim 1, characterized in that: Also includes: The optical fiber coupling structure is used for coupling the coaxial multi-wavelength diffracted light, and the optical fiber coupling structure is arranged along the axial direction of the coaxial multi-wavelength diffracted light.

3. The multi-wavelength laser modulation system according to claim 1, characterized in that: The RF driver providing the multi-frequency RF signal to the AOM comprises: The RF driver provides mixed RF signals of different frequencies to the AOM at the same time, and the AOM receives mixed RF signals of different frequencies from the RF driver at the same time; or, The RF driver provides RF signals of different frequencies to the AOM at different times, and the AOM receives a RF signal of a single frequency from the RF driver at the same time.

4. The multi-wavelength laser modulation system according to claim 3, characterized in that: The multi-frequency RF signal includes at least a first-frequency RF signal and a second-frequency RF signal, and the RF driver simultaneously provides a mixed signal of the first-frequency RF signal and the second-frequency RF signal to the AOM, or the RF driver provides the first-frequency RF signal to the AOM at a first time and provides the second-frequency RF signal to the AOM at a second time, and the RF driver alternately provides the first-frequency RF signal and the second-frequency RF signal.

5. The multi-wavelength laser modulation system according to claim 1, characterized in that: The light source provides coaxial multi-wavelength incident light to the AOM, comprising: The light source provides mixed incident light of different wavelengths to the AOM at the same time, and the AOM receives mixed incident light of different wavelengths from the AOM at the same time; or, The light source provides incident light of different wavelengths to the AOM at different times, and the AOM receives incident light of a single wavelength from the light source at the same time.

6. The multi-wavelength laser modulation system according to claim 5, characterized in that: The light source includes a plurality of independent light sources, and the plurality of independent light sources respectively provide incident light of different wavelengths to form mixed incident light of different wavelengths; or, The light source comprises a tunable light source, which provides incident light of different wavelengths at different times, and which provides incident light of a single wavelength at the same time.

7. The multi-wavelength laser modulation system according to claim 5 or 6, characterized in that: The difference between different wavelengths in the mixed incident light of different wavelengths is greater than a preset value.

8. The multi-wavelength laser modulation system according to claim 1, characterized in that: The coaxial multi-wavelength incident light includes at least a first wavelength incident light and a second wavelength incident light, the multi-frequency radio frequency signal includes at least a first frequency radio frequency signal and a second frequency radio frequency signal, the first wavelength incident light corresponds to the first frequency radio frequency signal, the second wavelength incident light corresponds to the second frequency radio frequency signal, and the product of the first wavelength and the first frequency is associated with the product of the second wavelength and the second frequency.

9. The multi-wavelength laser modulation system according to claim 1 or 6, characterized in that: Also includes: A clock generator is used to control the clocks of the light source and the radio frequency driver so that the incident light emitted by the light source and the radio frequency signal emitted by the radio frequency driver are synchronized in the acousto-optic modulator.

10. A method for modulating a multi-wavelength laser, characterized in that: The following steps are involved: Obtaining coaxial multi-wavelength incident light; Determining a multi-frequency radio frequency signal based on a fixed incident angle of the coaxial multi-wavelength incident light and a wavelength of the coaxial multi-wavelength incident light, wherein a frequency of the multi-frequency radio frequency signal corresponds to a wavelength of the coaxial multi-wavelength incident light; The coaxial multi-wavelength incident light is modulated by the multi-frequency radio frequency signal to form coaxial multi-wavelength diffracted light.

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