Wavelength tunable laser

Abstract

The invention discloses a wavelength tunable laser. The wavelength tunable laser comprises a base station; the resonant cavity is arranged on the base station; the gain medium is arranged on the base station and is positioned in the resonant cavity, so that the pump light forms oscillation light propagating in the resonant cavity when entering the gain medium, and the oscillation light forms output light of the tunable laser; the mode selecting part is arranged on the base station, is positioned on a propagation path of the oscillating light and is used for selecting light with corresponding wavelength from the oscillating light to form single longitudinal mode output light; and the first temperature control device is connected with the base station and is used for controlling the temperature of the base station to change the length of the resonant cavity so as to adjust the wavelength of the single longitudinal mode output light. The resonant cavity, the gain medium and the mode selection part are all arranged on the base station, the temperature of the base station is adjusted, the base station deforms due to the thermal expansion and cold contraction property, the length of the resonant cavity is changed, the oscillation light propagation optical path in the resonant cavity is changed, single longitudinal mode wavelength tuning of the wavelength tunable laser can be achieved, the structure is simple, and cost is low. And the tuning operation is relatively simple.

Description

Technical Field

[0001] This invention relates to the field of laser technology, and in particular to a wavelength-tunable laser. Background Technology

[0002] Wavelength-tunable single-mode lasers have many important applications in fields such as spectral analysis, optical measurement, communications, and life sciences. However, existing wavelength-tunable lasers have relatively complex structures. For example, the existing patent CN108400520A discloses a wavelength-continuously tunable single-mode semiconductor laser. By driving a linear motor to extend or retract the output shaft, the reflection angle of the grating can be changed by adjusting the rotation of the reflection grating around the adjustment shaft in large steps, so as to select the longitudinal mode reflection with the highest grating diffraction efficiency and form a central wavelength resonant laser. By fixing the extension of the linear motor, the reflection angle of the reflection grating is finely adjusted by a micro-displacement structure driven by piezoelectric ceramics, and the output wavelength is changed in microsteps. This requires controlling the linear motor and the micro-displacement structure to achieve mode selection and tuning, which is relatively complex to operate. Summary of the Invention

[0003] Therefore, the purpose of this invention is to provide a wavelength-tunable laser with a relatively simple structure.

[0004] To achieve the above objectives, the present invention provides the following technical solution:

[0005] A wavelength-tunable laser, comprising:

[0006] abutment;

[0007] A resonant cavity is disposed on the base plate;

[0008] A gain medium is disposed on the substrate and located within the resonant cavity, so that when pump light is incident on the gain medium, it forms oscillating light that propagates within the resonant cavity, and the oscillating light forms the output light of the wavelength-tunable laser;

[0009] A selection unit is disposed on the base and located in the propagation path of the oscillating light, and is used to select light of a corresponding wavelength from the oscillating light to form the output light;

[0010] A first temperature control device, connected to the base, is used to control the temperature of the base to change the length of the resonant cavity, thereby adjusting the wavelength of the output light.

[0011] Optionally, it also includes:

[0012] The second temperature control device is connected to the mold selection section and is used to control the temperature of the mold selection section.

[0013] Optionally, the second temperature control device is used to control the temperature of the mode selection section according to the following condition: Δv2·Δt2=Δv1·Δt1, where Δv2 represents the frequency shift caused by a 1°C temperature change in the mode selection section and the selected wavelength light, Δt2 represents the temperature change of the mode selection section, Δv1 represents the frequency shift caused by a 1°C temperature change in the base and the oscillating light, and Δt1 represents the temperature change of the base.

[0014] Optionally, the selection unit includes:

[0015] A parallel reflector includes a pair of parallel reflective surfaces for interfering with the oscillating light as it passes through the pair of parallel reflective surfaces, allowing light of a corresponding wavelength in the oscillating light to pass through.

[0016] Alternatively, a grating may be used to diffract the oscillating light as it passes through the grating, so as to select light of a corresponding wavelength from the oscillating light.

[0017] Optionally, the selection unit includes:

[0018] A first dielectric body, wherein the gain medium is disposed on one side of the first dielectric body, and the side of the first dielectric body away from the gain medium forms the end face of the resonant cavity, the first dielectric body includes a first pair of parallel reflective surfaces, such that the oscillating light interferes with the first pair of parallel reflective surfaces to select a corresponding wavelength of light from the oscillating light.

[0019] Optionally, the selection unit further includes:

[0020] A second dielectric body is disposed between the first dielectric body and the second dielectric body. The second dielectric body includes a second pair of parallel reflective surfaces, which cause the oscillating light to interfere through the second pair of parallel reflective surfaces, so as to select a corresponding wavelength of light from the oscillating light.

[0021] Optionally, it also includes:

[0022] The third temperature control device is connected to both the first medium and the second medium, and is used to control the temperature of the first medium and the second medium.

[0023] Optionally, the mode selection section includes a first mode selection section, which forms the input terminal of the resonant cavity:

[0024] Or / and, the mode selection section includes a second mode selection section, which forms the output terminal of the resonant cavity.

[0025] Optionally, it also includes:

[0026] A frequency conversion unit is disposed on the base and located in the propagation path of the oscillating light, and is used to convert the fundamental frequency light in the oscillating light into frequency-doubled light to form the output light.

[0027] Optionally, it also includes: a fourth temperature control device, connected to the frequency converter, for controlling the temperature of the frequency converter.

[0028] As can be seen from the above technical solution, the wavelength-tunable laser provided by the present invention includes: a base; a resonant cavity disposed on the base; a gain medium disposed on the base and located within the resonant cavity, such that when pump light is incident on the gain medium, it forms oscillating light propagating within the resonant cavity, and the oscillating light forms the output light of the wavelength-tunable laser; a mode selection unit disposed on the base and located in the propagation path of the oscillating light, used to select light of a corresponding wavelength from the oscillating light to form the output light; and a first temperature control device connected to the base, used to control the temperature of the base to change the length of the resonant cavity, thereby adjusting the wavelength of the output light.

[0029] In the wavelength-tunable laser of this invention, the resonant cavity, gain medium, and mode selection section are all disposed on a base. The temperature of the base is adjusted by a first temperature control device. Due to thermal expansion and contraction, the base deforms when the temperature changes, altering the length of the resonant cavity and changing the optical path of the oscillating light within it. This enables the tuning of the output wavelength of the wavelength-tunable laser. The wavelength-tunable laser of this invention has a relatively simple structure, and wavelength tuning can be achieved simply by controlling the temperature of the base, making operation relatively straightforward. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 A schematic diagram of a wavelength-tunable laser provided for the first embodiment;

[0032] Figure 2 A schematic diagram of a wavelength-tunable laser provided for the second embodiment.

[0033] The reference numerals in the accompanying drawings include:

[0034] 101-Base, 102-First temperature control device, 103-First dielectric, 104-Second dielectric, 105-Polarization element, 106-Cavity mirror, 107-Grate section, 108-Third temperature control device, 109-Fifth temperature control device, 110-Nonlinear crystal, 111-Fourth temperature control device. Detailed Implementation

[0035] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0036] This embodiment provides a wavelength-tunable laser, including:

[0037] abutment;

[0038] The resonant cavity is disposed on the base plate;

[0039] A gain medium is disposed on the substrate and located within the resonant cavity, so that when pump light is incident on the gain medium, it forms oscillating light that propagates within the resonant cavity, and the oscillating light forms the output light of the wavelength-tunable laser;

[0040] A selection unit is disposed on the base and located in the propagation path of the oscillating light, and is used to select light of a corresponding wavelength from the oscillating light to form the output light;

[0041] A first temperature control device, connected to the base, is used to control the temperature of the base to change the length of the resonant cavity, thereby adjusting the wavelength of the output light.

[0042] Pump light enters the resonant cavity and is incident on the gain medium, causing stimulated emission in the gain medium to achieve optical amplification, resulting in oscillating light propagating in the resonant cavity. When the oscillating light passes through the mode selection section, the corresponding wavelength of light in the oscillating light is selected to form the output light.

[0043] In this embodiment of the wavelength-tunable laser, the resonant cavity, gain medium, and mode selection section are all mounted on a base. The temperature of the base is adjusted by a first temperature control device. Due to thermal expansion and contraction, the base deforms when the temperature changes, altering the length of the resonant cavity and changing the optical path of the oscillating light within it. This results in wavelength tuning of the output light from the wavelength-tunable laser. This embodiment of the wavelength-tunable laser has a relatively simple structure, and wavelength tuning can be achieved simply by controlling the temperature of the base, making operation relatively straightforward.

[0044] In this embodiment of the wavelength-tunable laser, the mode selection unit can select a corresponding wavelength of light from the oscillating light propagating in the resonant cavity to form a single longitudinal mode output light, thereby outputting a single longitudinal mode laser. A first temperature control device controls the temperature of the base plate to change the length of the resonant cavity, enabling adjustment of the wavelength of the single longitudinal mode output light. This wavelength-tunable laser can achieve wavelength-tunable single longitudinal mode light output and is a type of wavelength-tunable single longitudinal mode laser.

[0045] The substrate exhibits thermal expansion and contraction properties, deforming with temperature changes and altering the length of the resonant cavity disposed on the substrate. For example, an increase in substrate temperature increases the length of the resonant cavity, while a decrease in substrate temperature decreases the length of the resonant cavity. The substrate may be referred to as a heat sink and can be, but is not limited to, a copper substrate or an aluminum substrate.

[0046] In this embodiment, the gain medium is not limited. In practical applications, gain media with different center wavelengths can be designed according to requirements, and semiconductor gain media, such as semiconductor quantum well gain media, can be used, but are not limited to. For example, frequency conversion technology can be combined, and the center wavelength of the gain medium can fully cover 400nm to 2000nm, and each center wavelength can achieve 50GHz-100GHz mode-hopping-free tuning with a coherence length >1m.

[0047] For some mode selection sections, the mode selection effect on the oscillating light is affected by temperature. If the length of the resonant cavity changes, the frequency of the oscillating light within the resonant cavity shifts, but the wavelength selected by the mode selection section remains unchanged, which can cause mode hopping during wavelength tuning of the wavelength-tunable laser. To address this, in some embodiments, the wavelength-tunable laser further includes a second temperature control device connected to the mode selection section for controlling the temperature of the mode selection section. By adjusting the temperature of the mode selection section through the second temperature control device, the wavelength of light selected by the mode selection section can be adjusted to correspond with the oscillating light within the resonant cavity, thus reducing the mode hopping phenomenon.

[0048] In some embodiments, the second temperature control device is used to control the temperature of the mode selection section according to the following conditional expression: Δv2·Δt2=Δv1·Δt1, where Δv2 represents the frequency shift of the wavelength light selected by the mode selection section when the temperature of the mode selection section changes by 1°C, Δt2 represents the temperature change of the mode selection section, Δv1 represents the frequency shift of the oscillating light when the temperature of the base plate changes by 1°C, and Δt1 represents the temperature change of the base plate. That is, the frequency shift of the wavelength light selected by the mode selection section caused by the temperature change of the mode selection section is the same as the frequency shift of the oscillating light in the resonant cavity caused by the temperature change of the base plate. This ensures that the oscillating light maintains a low-loss state during propagation in the resonant cavity when a frequency shift occurs, avoiding mode hopping during wavelength tuning and achieving mode-hopping-free wavelength tuning. During tuning of this wavelength-tunable laser, the temperature of the base plate can be adjusted by the first temperature control device and the temperature of the mode selection section can be adjusted by the second temperature control device according to the above conditional expression.

[0049] In this embodiment, the structure of the mode selection unit is not limited, as long as it can select the corresponding wavelength light from the oscillating light. In some embodiments, the mode selection unit includes a parallel reflector, which includes a pair of parallel reflective surfaces for interfering with the oscillating light as it passes through the pair of parallel reflective surfaces, allowing the corresponding wavelength light in the oscillating light to pass through. The structural and optical parameters of the parallel reflector can be set according to the mode selection requirements. The parallel reflector can be an etalon. In some embodiments, the mode selection unit includes a grating for diffraction of the oscillating light as it passes through the grating to select the corresponding wavelength light from the oscillating light. The structural and optical parameters of the grating can be set according to the mode selection requirements.

[0050] In some embodiments, the wavelength-tunable laser may further include a dielectric body, wherein the gain medium is disposed on one side of the dielectric body, and the side of the dielectric body away from the gain medium forms an end face of the resonant cavity. The placement of the gain medium on one side of the dielectric body, with the side of the dielectric body away from the gain medium forming an end face of the resonant cavity, allows for a compact structure of the wavelength-tunable laser. In some embodiments, the thermal conductivity of the dielectric body is greater than a preset value, resulting in good thermal conductivity, higher oscillating light energy within the resonant cavity, and stimulated emission occurring when passing through the gain medium, leading to a higher temperature in the gain medium. Using a dielectric body with good thermal conductivity optimizes heat dissipation of the gain medium.

[0051] In some embodiments, the mode selection unit includes: a first dielectric body, wherein the gain medium is disposed on one side of the first dielectric body, and the side of the first dielectric body away from the gain medium forms the end face of the resonant cavity. The first dielectric body includes a first pair of parallel reflecting surfaces, such that the oscillating light interferes with the first pair of parallel reflecting surfaces to select a corresponding wavelength light from the oscillating light. In this embodiment, the gain medium is disposed on the first dielectric body, and one side of the first dielectric body forms the end face of the resonant cavity. Furthermore, the first dielectric body also serves as the mode selection unit, enabling the wavelength-tunable laser to have a simple and compact structure. In some embodiments, the wavelength-tunable laser may further include: a third temperature control device connected to the first dielectric body for controlling the temperature of the first dielectric body. By controlling the temperature of the first dielectric body, which serves as the mode selection unit, the wavelength light selected by the first dielectric body can correspond to the oscillating light in the resonant cavity, reducing mode hopping.

[0052] In some embodiments, the mode selection unit further includes a second dielectric body, wherein the gain medium is disposed between the first dielectric body and the second dielectric body, and the second dielectric body includes a second pair of parallel reflective surfaces, such that the oscillating light interferes with the second pair of parallel reflective surfaces to select a corresponding wavelength light from the oscillating light. In this embodiment, the gain medium is disposed between the first dielectric body and the second dielectric body, and the second dielectric body also serves as a mode selection unit, which can optimize the mode selection function of the wavelength-tunable laser. In some embodiments, the wavelength-tunable laser may further include a third temperature control device connected to the second dielectric body for controlling the temperature of the second dielectric body. By controlling the temperature of the second dielectric body, which serves as the mode selection unit, the wavelength light selected by the second dielectric body can correspond to the oscillating light in the resonant cavity, reducing mode hopping.

[0053] In some embodiments, the thermal conductivity of the first dielectric body is greater than a preset value, giving it good thermal conductivity; or / and the thermal conductivity of the second dielectric body is greater than a preset value, giving it good thermal conductivity. The first and second dielectric bodies are respectively disposed on both sides of the gain medium. The good thermal conductivity of the first and / or second dielectric bodies allows for effective heat dissipation from the gain medium, contributing to improved operational stability and reliability of the wavelength-tunable laser. The first and second dielectric bodies form an optical-grade thermally conductive medium sandwich structure. The optical-grade thermally conductive medium requires low light absorption loss, and the thickness of the first and second dielectric bodies can be designed according to the thermal conductivity required for the pump light energy.

[0054] In some embodiments, the wavelength-tunable laser may further include a third temperature control device, connected to both the first and second dielectric bodies, for controlling the temperatures of the first and second dielectric bodies. See also, for example, [reference needed]. Figure 1 , Figure 1 A schematic diagram of a wavelength-tunable laser provided for the first embodiment is shown in the figure. The first dielectric body 103 and the second dielectric body 104 are both disposed on the base 101. The gain medium ( Figure 1 (Not shown) is disposed between the first dielectric body 103 and the second dielectric body 104. The gain medium can be in the shape of a thin sheet. The first temperature control device 102 is connected to the base 101, and the third temperature control device 108 is connected to both the first dielectric body 103 and the second dielectric body 104. In the figure, the straight line with an arrow pointing to the first dielectric body 103 indicates the propagation direction of the pump light, and the straight line with an arrow pointing out of the grating section 107 indicates the propagation direction of the output light.

[0055] The third temperature control device 108 can control the temperature of the first medium 103 and the second medium 104 according to the following condition: Δv 21 ·Δt 21 =Δv1·Δt1, where Δv 21The frequency shift Δt represents the amount of light shifted by the selected wavelength of light in the first dielectric 103 / second dielectric 104 when the temperature change of 1℃ in the first dielectric 103 / second dielectric 104 is expressed as follows: 21 The values ​​represent the temperature change of the first dielectric 103 / second dielectric 104, Δv1 represents the frequency shift of the oscillating light caused by a 1°C temperature change of the base, and Δt1 represents the temperature change of the base. That is, the frequency shift of the selected wavelength light caused by the temperature change of the first dielectric 103 / second dielectric 104 is the same as the frequency shift of the oscillating light in the resonant cavity caused by the temperature change of the base 101, which can avoid mode skipping during wavelength tuning. In some embodiments, the gain of the gain medium is maintained within a preset gain range within a preset temperature range, ensuring that the gain of the gain medium meets the requirements within the preset temperature range. This ensures that temperature changes in the first dielectric 103 or / and the second dielectric 104 do not affect the gain medium, allowing the gain medium to maintain a high gain over a wide temperature range.

[0056] The first temperature control device 102 can acquire the temperature value of the base 101 and control the temperature of the base 101 based on the acquired temperature value, thus possessing a feedback temperature control function and enabling precise temperature control. The third temperature control device 108 can acquire the temperature values ​​of the first dielectric 103 and the second dielectric 104 and control the temperatures of the first dielectric 103 and the second dielectric 104 based on the acquired temperature value, thus possessing a feedback temperature control function and enabling precise temperature control. The first temperature control device 102 or the third temperature control device 108 may be, but is not limited to, a semiconductor cooler.

[0057] In some embodiments, the mode selection section includes a grating section for causing diffraction of the oscillating light to select a corresponding wavelength of light from the oscillating light, and for reflecting the oscillating light to propagate within the resonant cavity. See, for example, [reference needed]. Figure 1 As shown, the grating section 107 is disposed on the base 101, serving not only as a mode selection section for selecting the mode of the oscillating light, but also constituting a resonant cavity to generate oscillating light propagating within the resonant cavity. For Figure 1 The laser shown, if the gain bandwidth of the gain medium is wide, will generate multiple longitudinal modes under the action of the first dielectric body 103 and the second dielectric body 104. Further, through the grating section 107, the wavelength bandwidth of the reflected fundamental frequency light is smaller than the interference transmission wavelength interval of the first dielectric body 103 and the second dielectric body 104, achieving single-longitudinal-mode fundamental frequency operation. This enables the wavelength-tunable laser to become a wavelength-tunable single-longitudinal-mode laser. The grating section 107 can be a reflective grating or a Bragg grating.

[0058] In some embodiments, the wavelength-tunable laser further includes a fifth temperature control device 109, connected to the grating section 107, for controlling the temperature of the grating section 107. By controlling the temperature of the grating section 107, which serves as a mode selection section, the wavelength light selected by the grating section 107 can correspond to the oscillating light in the resonant cavity, reducing mode hopping. The fifth temperature control device 109 can control the temperature of the grating section 107 according to the following conditional expression: Δv 22 ·Δt 22 =Δv1·Δt1, where Δv 22 The frequency shift Δt represents the amount of light of the selected wavelength produced by a temperature change of 1°C in the grating section 107. 22 The temperature change of the grating section 107 is represented by Δv1, the frequency shift of the oscillating light caused by a 1°C temperature change of the base is represented by Δt1, and the temperature change of the base is represented by Δt1. That is, the frequency shift of the selected wavelength light caused by the temperature change of the grating section 107 is the same as the frequency shift of the oscillating light in the resonant cavity caused by the temperature change of the base 101, which can avoid mode skipping during wavelength tuning. The fifth temperature control device 109 can acquire the temperature value of the grating section 107 and control the temperature of the grating section 107 based on the acquired temperature value, thus possessing the function of feedback temperature control and enabling precise temperature control. The fifth temperature control device 109 may employ, but is not limited to, a semiconductor cooler.

[0059] In some embodiments, the mode selection section includes a first mode selection section, which forms the input terminal of the resonant cavity. The first mode selection section not only selects the mode of the oscillating light within the resonant cavity but also forms the input terminal of the resonant cavity, thus simplifying the structure of the wavelength-tunable laser. Pump light can pass through the first mode selection section into the resonant cavity and be incident on the gain medium. In some embodiments, the mode selection section includes a second mode selection section, which forms the output terminal of the resonant cavity. The second mode selection section not only selects the mode of the oscillating light within the resonant cavity but also forms the output terminal of the resonant cavity, thus simplifying the structure of the wavelength-tunable laser. Output light can exit the resonant cavity from the second mode selection section. In some embodiments, the mode selection section includes a first mode selection section and a second mode selection section. The first mode selection section forms the input terminal of the resonant cavity, and the second mode selection section forms the output terminal of the resonant cavity, resulting in a simple and compact structure for the wavelength-tunable laser. Examples can be found by referring to... Figure 1 As shown, the first dielectric body 103 serves as the input end of the resonant cavity, and the grating section 107 serves as the output end of the resonant cavity. The pump light enters the resonant cavity through the first dielectric body 103, and the resulting output light is emitted from the grating section 107.

[0060] In some embodiments, the wavelength-tunable laser may further include a frequency conversion unit disposed on the base 101 and located in the propagation path of the oscillating light, for converting the fundamental frequency light in the oscillating light into frequency-doubled light to form output light, thereby expanding the output wavelength range of the wavelength-tunable laser. The frequency conversion unit may employ a nonlinear crystal, which may be, but is not limited to, lithium triborate (LBO) crystals, periodically polarized lithium niobate (PPLN) crystals, or periodically polarized magnesium-doped lithium niobate (PPMgLN) crystals. In embodiments including a first dielectric body 103, a second dielectric body 104, and a gain medium disposed between the first dielectric body 103 and the second dielectric body 104, the side of the second dielectric body 104 away from the gain medium can transmit the fundamental frequency light and reflect the frequency-doubled light, so that the frequency-doubled light forms output light, and the side of the first dielectric body 103 away from the gain medium can reflect the fundamental frequency light.

[0061] In some embodiments, the wavelength-tunable laser may further include a fourth temperature control device 111, connected to the frequency converter, for controlling the temperature of the frequency converter. The conversion efficiency of some frequency converters varies with the optical frequency. When adjusting the temperature of the base 101 for wavelength tuning, the oscillating light undergoes a frequency shift. The conversion efficiency of the frequency converter can be adjusted accordingly by adjusting the temperature of the frequency converter, thus providing temperature compensation for the change in conversion efficiency with frequency shift. The fourth temperature control device 111 can acquire the temperature value of the frequency converter and control the temperature of the frequency converter based on the acquired temperature value, possessing a feedback temperature control function and enabling precise temperature control. The fourth temperature control device 111 may employ, but is not limited to, a semiconductor cooler. For example, see [reference needed]. Figure 2 , Figure 2 A schematic diagram of a wavelength-tunable laser provided for the second embodiment is shown in the figure. A nonlinear crystal 110 is disposed on a base 101, and a fourth temperature control device 111 is disposed below the nonlinear crystal 110.

[0062] In some embodiments, the wavelength-tunable laser may further include a cavity mirror 106 disposed within the resonant cavity and positioned along the propagation path of the oscillating light. The oscillating light propagates within the resonant cavity and passes through the cavity mirror 106, which creates a beam waist at both ends of the resonant cavity. This results in the formation of oscillating light that propagates stably within the resonant cavity, and in embodiments with a frequency conversion section, it can improve the frequency doubling conversion efficiency. The cavity mirror 106 may be a positive lens. In some embodiments, the wavelength-tunable laser may further include a polarizing element 105 disposed within the resonant cavity and positioned along the propagation path of the oscillating light, serving a polarizing function. The polarizing element 105 may be a polarizer.

[0063] In this embodiment, the structure of the resonant cavity is not limited; it can be a linear cavity, a folded cavity, or a resonant cavity of other structures. The pump source used is not limited; a semiconductor laser diode can be used.

[0064] For example, for Figure 1 In the laser shown, the side of the first dielectric body 103 away from the second dielectric body 104 serves as the pump end face, where an anti-reflection coating corresponding to the pump light and a high-reflection coating corresponding to the fundamental frequency light can be disposed, and it is used as one end mirror of the resonant cavity. The side of the second dielectric body 104 away from the first dielectric body 103 can be disposed with an anti-reflection coating corresponding to the fundamental frequency light. The polarization element 105 can be an uncoated Brewster angle incident element. The two light-transmitting surfaces of the cavity mirror 106 can be disposed with anti-reflection coatings corresponding to the fundamental frequency light. The two light-transmitting surfaces of the grating section 107 can be disposed with anti-reflection coatings corresponding to the fundamental frequency light, and a suitable fundamental frequency light diffraction efficiency is designed, with its reflection center wavelength bandwidth being smaller than the wavelength interval of the interference transmission peaks of the first dielectric body 103 and the second dielectric body 104, and it is used as the output end mirror.

[0065] For example, for Figure 2 In the laser shown, the side of the first dielectric body 103 away from the second dielectric body 104 serves as the pump end face, where an anti-reflection coating corresponding to the pump light and a high-reflection coating corresponding to the fundamental frequency light can be provided, and it is used as one end mirror of the resonant cavity. The side of the second dielectric body 104 away from the first dielectric body 103 can also be provided with an anti-reflection coating corresponding to the fundamental frequency light and a high-reflection coating corresponding to the frequency-doubled light. The polarization element 105 can be an uncoated Brewster angle incident element. The two light-transmitting surfaces of the cavity mirror 106 can be provided with anti-reflection coatings corresponding to the fundamental frequency light and the frequency-doubled light. The two light-transmitting surfaces of the nonlinear crystal 110 can be provided with anti-reflection coatings corresponding to the fundamental frequency light and the frequency-doubled light. The two light-transmitting surfaces of the grating section 107 can be provided with anti-reflection coatings corresponding to the fundamental frequency light and the frequency-doubled light, which have high diffraction efficiency for the fundamental frequency light and reflect the fundamental frequency wavelength bandwidth is smaller than the interference transmission wavelength interval of the first dielectric body 103 and the second dielectric body 104, and it is used as the output end mirror.

[0066] In this embodiment, when calculating the frequency shift caused by the change in the optical length of the resonant cavity during wavelength tuning of the tunable laser, it is necessary to consider all optical components within the resonant cavity to achieve mode-hopping-free tuning. This embodiment of the wavelength-tunable laser can achieve stable high-power single-longitudinal-mode laser output without electromechanical control system tuning. The resonant cavity structure is simple and compact, with good wavelength stability, allowing for small-size packaged products. Furthermore, it boasts high output power, with an optical-to-optical conversion efficiency >25%, achieving output power from hundreds of milliwatts to watts without amplification.

[0067] The wavelength-tunable laser provided by this invention has been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the embodiments above are merely for the purpose of helping to understand the method and core ideas of this invention. It should be noted that those skilled in the art can make various improvements and modifications to this invention without departing from its principles, and these improvements and modifications also fall within the protection scope of this invention.

Claims

1. A wavelength tunable laser, characterized by, The wavelength tunable laser comprises: a base; a resonant cavity arranged on the base; a gain medium arranged on the base and in the resonant cavity, so that when pump light is incident on the gain medium, oscillation light is formed in the resonant cavity, and the output light of the wavelength tunable laser is formed by the oscillation light; a mode selection unit arranged on the base and in the propagation path of the oscillation light, for selecting corresponding wavelength light from the oscillation light to form the output light; a first temperature control device connected to the base, for controlling the temperature of the base to change the length of the resonant cavity, so as to adjust the wavelength of the output light.

2. The wavelength tunable laser of claim 1, wherein, Further comprising: a second temperature control device connected to the mode selection unit, for controlling the temperature of the mode selection unit.

3. The wavelength tunable laser of claim 2, wherein, The second temperature control device is used to control the temperature of the mode selection unit according to the following conditional expression: Δv2·Δt2=Δv1·Δt1, wherein Δv2 represents the frequency shift amount of the wavelength light selected by the mode selection unit when the temperature of the mode selection unit changes by 1℃, Δt2 represents the temperature change amount of the mode selection unit, Δv1 represents the frequency shift amount of the oscillation light when the temperature of the base changes by 1℃, and Δt1 represents the temperature change amount of the base.

4. The wavelength tunable laser of claim 1, wherein, The mode selection unit comprises: a parallel reflection unit comprising a pair of parallel reflection surfaces, for causing the oscillation light to interfere through the pair of parallel reflection surfaces, so that corresponding wavelength light in the oscillation light passes through; or a grating, for causing the oscillation light to diffract through the grating, so as to select corresponding wavelength light from the oscillation light.

5. The wavelength tunable laser of claim 1, wherein, The mode selection unit comprises: a first medium body, the gain medium is arranged on one side of the first medium body, the side of the first medium body away from the gain medium forms an end surface of the resonant cavity, and the first medium body comprises a first pair of parallel reflection surfaces, so that the oscillation light interferes through the first pair of parallel reflection surfaces to select corresponding wavelength light from the oscillation light.

6. The wavelength tunable laser of claim 5, wherein, The mode selection unit further comprises: a second medium body, the gain medium is arranged between the first medium body and the second medium body, and the second medium body comprises a second pair of parallel reflection surfaces, so that the oscillation light interferes through the second pair of parallel reflection surfaces to select corresponding wavelength light from the oscillation light.

7. The wavelength tunable laser of claim 6, wherein, Further comprising: a third temperature control device connected to the first medium body and the second medium body, for controlling the temperature of the first medium body and the second medium body.

8. The wavelength tunable laser of claim 1, wherein, The mode selection unit comprises a first mode selection unit, and the first mode selection unit forms an input end of the resonant cavity. Or / and, the mode selection unit comprises a second mode selection unit, and the second mode selection unit forms an output end of the resonant cavity.

9. The wavelength tunable laser according to any one of claims 1 to 8, characterized in that, Further comprising: a frequency conversion unit arranged on the base and in the propagation path of the oscillation light, for converting fundamental frequency light in the oscillation light into frequency-doubled light to form the output light.

10. The wavelength tunable laser of claim 9, wherein, Further comprising: a fourth temperature control device connected to the frequency conversion unit, for controlling the temperature of the frequency conversion unit.

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