A wide-tuning laser

Abstract

This disclosure provides a wide-tunable laser, comprising a first laser module, an external cavity module, and a second laser module connected in sequence. The end face of the first laser module away from the external cavity module has a first reflective film, and the end face of the second laser module away from the external cavity module has a second reflective film. The reflectivity of the first reflective film is greater than that of the second reflective film. The first laser module or the second laser module is used to generate an optical signal and inject it into the external cavity module. The external cavity module is used to narrow the linewidth of the optical signal and perform mode selection on the optical signal, transmitting the optical signal that satisfies a preset mode to the second laser module or the first laser module. The optical signal that satisfies the preset mode travels back and forth multiple times between the first reflective film, the external cavity module, and the second reflective film to form laser oscillation, and is output through the second reflective film.

Description

Technical Field

[0001] This disclosure relates to the field of lasers, and more particularly to a wide-tunable laser. Background Technology

[0002] A tunable laser is a laser whose output wavelength can be continuously changed within a certain range. These lasers have a wide range of applications, including spectroscopy, photochemistry, medicine, biology, integrated optics, pollution monitoring, semiconductor material processing, information processing, and communications. Tunable fiber lasers, in particular, have significant application value in wavelength division multiplexing systems, distributed fiber optic sensing systems, and microwave photonics technology due to their advantages such as compact structure, low cost, and high stability. Therefore, achieving stable and tunable fiber laser output is of great importance.

[0003] Currently, the tunable range of tunable lasers is relatively small, making them unable to meet the needs of various application scenarios. Furthermore, in order to broaden their tunable range, more components need to be added, resulting in high system complexity, high cost, and high losses, which adversely affect the efficiency and stability of the laser.

[0004] Therefore, it is necessary to provide an improved technical solution to address the problems existing in tunable lasers. Summary of the Invention

[0005] In view of this, embodiments of the present disclosure provide a wide-tuning laser.

[0006] To achieve the above objectives, the technical solution disclosed herein is implemented as follows:

[0007] This disclosure provides a wide-tunable laser, comprising a first laser module, an external cavity module, and a second laser module connected in sequence. The end face of the first laser module away from the external cavity module has a first reflective film, and the end face of the second laser module away from the external cavity module has a second reflective film. The reflectivity of the first reflective film is greater than that of the second reflective film. The first laser module or the second laser module is used to generate an optical signal and inject it into the external cavity module. The external cavity module is used to narrow the linewidth of the optical signal and perform mode selection on the optical signal, transmitting the optical signal that satisfies a preset mode to the second laser module or the first laser module. The optical signal that satisfies the preset mode travels back and forth multiple times between the first reflective film, the external cavity module, and the second reflective film to form laser oscillation, and is output through the second reflective film.

[0008] In some embodiments, the first laser module is used to generate an optical signal having a first tunable band, and the second laser module is used to generate an optical signal having a second tunable band, wherein the first tunable band is different from the second tunable band.

[0009] In some embodiments, the reflection band of the first reflective film at least covers the first tunable band and the second tunable band, and the reflection band of the second reflective film at least covers the first tunable band and the second tunable band.

[0010] In some embodiments, the external cavity module includes at least three waveguides arranged along a first direction, the extension direction of the waveguides intersecting the first direction; a micro-ring is disposed between any two adjacent waveguides among the at least three waveguides.

[0011] In some embodiments, the free spectral path of each of the microrings is different.

[0012] In some embodiments, a first modulation unit is disposed on the first waveguide and the last waveguide, wherein the first modulation unit is a phase modulator.

[0013] In some embodiments, at least one of the microrings is provided with a second modulation unit, which is a thermal modulator or an electro-optic modulator.

[0014] In some embodiments, the microring is a racetrack-shaped microring, and the straight waveguide portion of the racetrack-shaped microring is coupled to two adjacent waveguides.

[0015] In some embodiments, the end face of the first laser module connected to the external cavity module has a first antireflection film, and the end face of the second laser module connected to the external cavity module has a second antireflection film.

[0016] In some embodiments, the wide-tunable laser further includes: a first coupling unit connected between the first laser module and a first end of the external cavity module, the first coupling unit being used to couple an optical signal output by the first laser module to the first end of the external cavity module, or to couple an optical signal output by the first end of the external cavity module to the first laser module; a second coupling unit connected between the second laser module and a second end of the external cavity module, the second coupling unit being used to couple an optical signal output by the second laser module into the second end of the external cavity module, or to couple an optical signal output by the second end of the external cavity module into the second laser module; the first end and the second end of the external cavity module are two opposite end faces of the external cavity module.

[0017] This disclosure provides a wide-tunable laser, comprising a first laser module, an external cavity module, and a second laser module connected in sequence. The end face of the first laser module away from the external cavity module has a first reflective film, and the end face of the second laser module away from the external cavity module has a second reflective film. The reflectivity of the first reflective film is greater than that of the second reflective film. The first laser module or the second laser module is used to generate an optical signal and inject it into the external cavity module. The external cavity module is used to narrow the linewidth of the optical signal and perform mode selection on the optical signal, transmitting the optical signal that satisfies a preset mode to the second laser module or the first laser module. The optical signal that satisfies the preset mode travels back and forth multiple times between the first reflective film, the external cavity module, and the second reflective film to form laser oscillation, and is output through the second reflective film. This embodiment integrates a first laser module, an external cavity module, and a second laser module. Different optical signals are generated and tuned using either the first or second laser module in different scenarios. This allows the tunable range of the laser provided in this embodiment to fully cover the tuning ranges of both the first and second laser modules, thus widening the laser's tuning range. Furthermore, the optical signals generated by either the first or second laser module can be tuned separately in different scenarios. Therefore, the increased tuning range does not affect the laser's tuning accuracy or tuning difficulty. The laser provided in this embodiment can also form a single-mode laser oscillation between the first reflective film, the external cavity module, and the second reflective film, and this oscillation is amplified by either the first or second laser module, enabling the output of a high-power, narrow-linewidth single-mode laser. Attached Figure Description

[0018] Figure 1 A schematic diagram of the structure of a wide-tunable laser provided in the embodiments of this disclosure. Figure 1 ;

[0019] Figure 2 for Figure 1 A schematic diagram of the resonance spectrum of the external cavity module shown;

[0020] Figure 3 A schematic diagram of the structure of a wide-tunable laser provided in the embodiments of this disclosure. Figure 2 ;

[0021] Figure 4 This is a schematic diagram of the structure of the microring provided in an embodiment of this disclosure. Detailed Implementation

[0022] The technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this disclosure, and not all of them. Based on the embodiments in this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0023] In the following description, numerous specific details are set forth in order to provide a more thorough understanding of this disclosure. However, it will be apparent to those skilled in the art that this disclosure may be practiced without one or more of these details. In other instances, to avoid confusion with this disclosure, certain technical features well-known in the art have not been described; that is, not all features of actual embodiments are described herein, nor are well-known functions and structures described in detail.

[0024] In the accompanying drawings, for clarity, the dimensions of layers, areas, and elements, as well as their relative dimensions, may be exaggerated. The same reference numerals denote the same elements throughout.

[0025] It should be understood that when an element or layer is referred to as "on," "adjacent to," "connected to," or "coupled to" other elements or layers, it may be directly on, adjacent to, connected to, or coupled to other elements or layers, or there may be intervening elements or layers. Conversely, when an element is referred to as "directly on," "directly adjacent to," "directly connected to," or "directly coupled to" other elements or layers, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc., may be used to describe various elements, components, areas, layers, and / or portions, these elements, components, areas, layers, and / or portions should not be limited by these terms. These terms are only used to distinguish one element, component, area, layer, or portion from another element, component, area, layer, or portion. Therefore, without departing from the teachings of this disclosure, the first element, component, area, layer, or portion discussed below may be referred to as a second element, component, area, layer, or portion. And the discussion of a second element, component, area, layer, or portion does not imply that the first element, component, area, layer, or portion necessarily exists in this disclosure.

[0026] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. When used herein, the singular forms “a,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprise” and / or “comprising,” when used in this specification, identify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups. When used herein, the term “and / or” includes any and all combinations of the associated listed items.

[0027] To fully understand this disclosure, detailed steps and structures will be presented in the following description to illustrate the technical solutions of this disclosure. Preferred embodiments of this disclosure are described in detail below; however, other embodiments may also be implemented in addition to these detailed descriptions.

[0028] It should be noted that, for ease of description, the various directions that may be used in the following description are first defined. The extension direction of the waveguide in the external cavity module is defined as the X direction, and the arrangement direction of the waveguide in the external cavity module is defined as the Y direction (the first direction), where the X direction and the Y direction can be perpendicular to each other.

[0029] Figure 1 A schematic diagram of the structure of a wide-tunable laser provided in the embodiments of this disclosure. Figure 1 See also Figure 1 The wide-tunable laser includes a first laser module 10, an external cavity module 20, and a second laser module 30 connected in sequence. The end face of the first laser module 10 away from the external cavity module 20 has a first reflective film 11, and the end face of the second laser module 30 away from the external cavity module 20 has a second reflective film 31. The reflectivity of the first reflective film 11 is greater than that of the second reflective film 31. The first laser module 10 or the second laser module 30 is used to generate an optical signal and inject it into the external cavity module 20. The external cavity module 20 is used to narrow the linewidth of the optical signal and perform mode selection on the optical signal, transmitting the optical signal that meets the preset mode to the second laser module 30 or the first laser module 10. The optical signal that meets the preset mode travels back and forth multiple times between the first reflective film 11, the external cavity module 20, and the second reflective film 31 to form laser oscillation, and is output through the second reflective film 31.

[0030] In some embodiments, the end face of the first laser module 10 having the first reflective film 11 is the first end face, and the end face of the first laser module 10 connected to the external cavity module 20 is the second end face; the end face of the second laser module 30 having the second reflective film 31 is the third end face, and the end face of the second laser module 30 connected to the external cavity module 20 is the fourth end face.

[0031] In some embodiments, current can be injected into the first laser module 10 to excite the gain medium in the first laser module 10 to generate an optical signal, which is transmitted along a first optical path. The optical signal is injected into the first end 201 of the external cavity module 20 through the second end face of the first laser module 10. The external cavity module 20 can cause the portion of the optical signal that satisfies a preset mode to resonate, thereby amplifying the optical signal that satisfies the preset mode and achieving mode selection. It should be noted that the first end and the second end of the external cavity module are two opposite end faces of the external cavity module.

[0032] The external cavity module 20 also transmits the optical signal that meets the preset mode to the second laser module 30 through the second end 202. Afterwards, the optical signal is reflected by the second reflective film 31 and transmitted along the second optical path to the first laser module 10, and then reflected by the first reflective film 11 and transmitted along the first optical path to the second laser module 30. This allows the optical signal to travel back and forth multiple times between the first reflective film 11, the external cavity module 20, and the second reflective film 31 to form single-mode laser oscillation. Furthermore, during the oscillation process, the optical signal can be repeatedly amplified by the gain medium in the first laser module 10, enabling the laser to output high-power, narrow-linewidth single-mode laser from the end with lower reflectivity (the second reflective film 31). It should be noted that the first optical path is from the first reflective film to the first end of the external cavity module to the second end of the external cavity module to the second reflective film, and the second optical path is from the second reflective film to the second end of the external cavity module to the first end of the external cavity module to the first reflective film.

[0033] In other embodiments, current can be injected into the second laser module 30 to excite the gain medium in the second laser module 30 to generate an optical signal, which is transmitted along a second optical path. The optical signal is injected into the second end 202 of the external cavity module 20 through the fourth end face of the second laser module 30. The external cavity module 20 can cause the portion of the optical signal that satisfies a preset mode to resonate, thereby enhancing the optical signal that satisfies the preset mode and thus achieving mode selection.

[0034] The external cavity module 20 also transmits the optical signal that meets the preset mode to the first laser module 10 through the first end 201. Then, after being reflected by the first reflective film 11, the optical signal is transmitted to the second laser module 30 along the first optical path, and after being reflected by the second reflective film 31, it is transmitted to the first laser module 10 along the second optical path. This allows the optical signal to travel back and forth multiple times between the first reflective film 11, the external cavity module 20, and the second reflective film 31 to form a single-mode laser oscillation. During the oscillation process, the optical signal can be repeatedly enhanced by the gain medium in the second laser module 30, so that the laser can output a high-power, narrow-linewidth single-mode laser from the end with lower reflectivity (the second reflective film 31).

[0035] In some embodiments, the reflectivity of the first reflective film 11 may be greater than or equal to 90%, and the reflectivity of the second reflective film 31 may be less than or equal to 10%.

[0036] In some embodiments, by integrating the first laser module, the external cavity module, and the second laser module, current is injected into the first laser module or the second laser module in different scenarios to generate different optical signals and tune the optical signals. This allows the tunable range of the laser provided in this disclosure to fully cover the tuning ranges of the first laser module and the second laser module, thus widening the laser's tuning range. Furthermore, the optical signals generated by the first laser module or the second laser module can be tuned separately in different scenarios. Therefore, the widening of the tuning range does not affect the laser's tuning accuracy or tuning difficulty. By forming a single-mode laser oscillation between the first reflective film, the external cavity module, and the second reflective film, and amplifying the oscillation during the process by the first laser module or the second laser module, a high-power, narrow-linewidth single-mode laser can be output.

[0037] In some embodiments, a first laser module is used to generate an optical signal having a first tunable band, and a second laser module is used to generate an optical signal having a second tunable band, wherein the first tunable band and the second tunable band are different.

[0038] In some embodiments, the first laser module and the second laser module can respectively generate optical signals with a first tunable wavelength band and a second tunable wavelength band. This expands the tunable range of the laser to the union of the first and second tunable wavelength bands. Furthermore, during tuning, the optical signals generated by either the first or second laser module can be tuned separately, avoiding the problems of low tuning accuracy, high tuning difficulty, and long tuning time that can arise from the expanded tuning range. Therefore, the laser provided in this disclosure has the characteristics of wide tuning range, high accuracy, simple tuning, and short tuning time.

[0039] In one specific embodiment, the first laser module 10 is an S-band laser gain chip, thus enabling the first laser module to generate S-band optical signals; the second laser module 30 is a C+L band laser gain chip, thus enabling the second laser module 30 to generate C+L band optical signals. In this case, the tunable range of the laser provided in this embodiment is the S+C+L band. It should be noted that the wavelength range of the S-band is 1460nm to 1530nm, the wavelength range of the C-band is 1530nm to 1565nm, and the wavelength range of the L-band is 1565nm to 1625nm.

[0040] In some embodiments, the external cavity module includes at least three waveguides arranged along a first direction, the extension direction of which intersects the first direction; a micro-ring is disposed between any two adjacent waveguides among the at least three waveguides.

[0041] Figure 1 The external cavity module 20, comprising four waveguides arranged along the first direction, will be used as an example for illustration. (See also...) Figure 1 The external cavity module 20 includes four waveguides arranged along the Y direction: waveguide 211, waveguide 212, waveguide 213, and waveguide 214. A microring 221 is disposed between waveguide 211 and waveguide 212, a microring 222 is disposed between waveguide 212 and waveguide 213, and a microring 223 is disposed between waveguide 213 and waveguide 214. It should be noted that the microrings in this disclosure can be circular, racetrack-shaped, or elliptical, and this disclosure does not impose any restrictions on them.

[0042] In some embodiments, the coupling coefficient between the microring and the waveguide can be around 0.15 to ensure the transmission efficiency of the optical signal in the external cavity module. The Q value (quality factor) of the microring can reach the order of 1E5 or higher to improve the sensitivity of the external cavity module.

[0043] In some embodiments, the optical signal can be transmitted in the external cavity module 20 along a first optical path: coupled from waveguide 211 to microring 221 and resonating in microring 221, coupled from microring 221 to waveguide 212, coupled from waveguide 212 to microring 222 and resonating in microring 222, coupled from microring 222 to waveguide 213, coupled from waveguide 213 to microring 223 and resonating in microring 223, and coupled from microring 223 to waveguide 214.

[0044] In some embodiments, the optical signal can be transmitted in the external cavity module 20 along a second optical path: coupled from waveguide 214 to microring 223 and resonating in microring 223, coupled from microring 223 to waveguide 213, coupled from waveguide 213 to microring 222 and resonating in microring 222, coupled from microring 222 to waveguide 212, coupled from waveguide 212 to microring 221 and resonating in microring 221, and coupled from microring 221 to waveguide 211.

[0045] In some embodiments, the mode selection wavelength of the external cavity module can be adjusted to a preset mode by adjusting the resonant wavelength of each microring in the external cavity module.

[0046] It should be noted that the number of waveguides in the external cavity module is one more than the number of microrings. This embodiment of the present disclosure does not impose any other restrictions on the number of waveguides and microrings in the external cavity module.

[0047] In some embodiments, the free spectral path of each microring is different.

[0048] In some embodiments, the perimeter of the microrings can be designed so that each microring has a different free spectral range (FSR).

[0049] In some embodiments, when the free spectral path difference between at least two microrings in the external cavity module is small, the external cavity module can have a large effective free spectral path. By increasing the number of microrings in the external cavity module, not only can the free spectral path of the external cavity module be increased, but the side mode suppression ratio (SMSR) of the external cavity module 20 can also be effectively improved, which helps to improve the stability of the single-mode laser output by the laser.

[0050] In some embodiments, the external cavity module includes at least four waveguides arranged along the Y direction, and in this case, the external cavity module may include at least three microrings. By designing the parameters of the at least three microrings, the free spectral path difference of at least two microrings is less than or equal to a first preset value and greater than zero. The range of the first preset value can be set according to requirements, for example, 0.4 nm, 0.6 nm, 0.8 nm, or 1.0 nm. In this way, the external cavity module can simultaneously possess the characteristics of a large tuning range, high side-mode suppression ratio, and good stability.

[0051] Figure 2 for Figure 1 A schematic diagram of the resonance spectrum of the external cavity module shown. (See also...) Figure 2 In a specific example, Figure 1 The free spectral paths of microrings 221, 222, and 223 are 1.567 nm, 1.912 nm, and 1.554 nm, respectively. In this case, the differences in the free spectral paths of the three microrings are small (all less than 0.4 nm). Therefore, the free spectral path of the external cavity module 20 can reach [a certain value]. Figure 2 The 225nm shown allows the external cavity module 20 to have a very large free tuning range, while also possessing good tuning accuracy, side-mode suppression ratio, and good stability.

[0052] In some embodiments, a first modulation unit is disposed on the first waveguide and the last waveguide, and the first modulation unit is a phase modulator.

[0053] Figure 3 A schematic diagram of the structure of a wide-tunable laser provided in the embodiments of this disclosure. Figure 2 See also Figure 3 In the external cavity module 20, a first modulation unit 231 is provided on waveguide 211, and a first modulation unit 232 is provided on waveguide 214.

[0054] When the first laser module 10 injects an optical signal into the external cavity module 20, the first terminal 201 can be regarded as the input terminal of the external cavity module 20. By changing the voltage intensity applied to the first modulation unit 231, the modulation parameters of the first modulation unit 231 can be adjusted, effectively controlling the phase of the optical signal entering the external cavity module 20, thereby adjusting the wavelength of the laser output and ensuring the wide-range tuning capability of the laser.

[0055] When the second laser module 30 injects an optical signal into the external cavity module 20, the second terminal 202 can be regarded as the input terminal of the external cavity module 20. By changing the voltage intensity applied to the first modulation unit 232, the modulation parameters of the first modulation unit 232 can be adjusted, effectively controlling the phase of the optical signal entering the external cavity module 20, thereby adjusting the wavelength of the laser output and ensuring the wide-range tuning capability of the laser.

[0056] In some embodiments, at least one microring is provided with a second modulation unit, which is a thermal modulator or an electro-optic modulator.

[0057] See Figure 3 The micro-rings 221, 222 and 223 are respectively provided with a second modulation unit 241, a second modulation unit 242 and a second modulation unit 243.

[0058] When the second modulation unit is a thermal modulator (e.g., a thermoelectrode), adjusting the voltage on the second modulation unit changes the temperature of the corresponding microring. This temperature change causes a change in the microring's refractive index, thus altering its resonant wavelength. In this way, the second modulation unit can be used to change the microring's resonant wavelength, thereby adjusting the mode selection wavelength of the external cavity module and achieving tunable output laser light from the laser.

[0059] When the second modulation unit is an electro-optic modulator, by adjusting the electric field applied to the second modulation unit, the refractive index of the second modulation unit itself is changed, thereby affecting the effective refractive index of the microring and thus changing the resonant wavelength of the microring.

[0060] In some embodiments, the mode selection wavelength of the external cavity module 20 can be adjusted by adjusting the modulation parameters of the first modulation unit 231 or the first modulation unit 232 and adjusting the control parameters (voltage or electric field) of the second modulation unit on the microring, thereby tuning the output laser of the laser.

[0061] In some embodiments, see Figure 3The wide-tunable laser further includes: a first coupling unit 41 connected between the first laser module 10 and the first end 201 of the external cavity module 20, the first coupling unit 41 being used to couple the optical signal output by the first laser module 10 to the first end 201 of the external cavity module 20, or to couple the optical signal output by the first end 201 of the external cavity module 20 to the first laser module 10; a second coupling unit 42 connected between the second laser module 30 and the second end 202 of the external cavity module 20, the second coupling unit 42 being used to couple the optical signal output by the second laser module 30 into the second end 202 of the external cavity module 20, or to couple the optical signal output by the second end 202 of the external cavity module 20 into the second laser module 30; the first end 201 and the second end 202 of the external cavity module 20 are two opposite end faces of the external cavity module 20.

[0062] See Figure 3 The first coupling unit 41 and the second coupling unit 42 can be mode converters. The first coupling unit 41 is used to adjust the spot size of the optical signal to match the mode size between the second end face of the first laser module 10 and the first end 201 of the external cavity module 20, thereby improving the coupling efficiency between the first laser module 10 and the first end 201 of the external cavity module 20 and avoiding unnecessary losses in the optical signal during transmission. The second coupling unit 42 is used to adjust the spot size of the optical signal to match the mode size between the second end face of the second laser module 30 and the second end 202 of the external cavity module 20, thereby improving the coupling efficiency between the second laser module 30 and the second end 202 of the external cavity module 20 and avoiding unnecessary losses in the optical signal during transmission.

[0063] In some embodiments, the reflection band of the first reflective film at least covers the first tunable band and the second tunable band, and the reflection band of the second reflective film at least covers the first tunable band and the second tunable band.

[0064] In some embodiments, the reflection bands of the first and second reflective films can fully cover both the first and second tunable bands to avoid the loss of laser tuning range due to the inability to effectively reflect optical signals in some bands. In a specific example, if the first laser module is an S-band laser gain chip and the second laser module is a C+L band laser gain chip, then the reflection bands of the first and second reflective films can be S+C+L bands.

[0065] In some embodiments, see Figure 3 The first laser module 10 has a first antireflection film 12 on the end face near the external cavity module 20, and the second laser module 30 has a second antireflection film 32 on the end face near the external cavity module 20.

[0066] In some embodiments, the second end face of the first laser module 10 is coated with a first antireflection film 12, which helps to reduce the optical loss inside the first laser module 10 and improve the transmission efficiency of the output signal of the first laser module 10. The second end face of the second laser module 30 is coated with a second antireflection film 32, which helps to reduce the optical loss inside the second laser module 30 and improve the transmission efficiency of the output signal of the second laser module 30.

[0067] In some embodiments, the antireflection bands of the first antireflection film and the second antireflection film can fully cover the first tunable band and the second tunable band, so as to avoid the optical signals of some bands being unable to effectively pass through the first antireflection film or the second antireflection film, resulting in the loss of the laser's tuning range.

[0068] In some embodiments, the microring is a racetrack-shaped microring, and the straight waveguide portion of the racetrack-shaped microring is coupled to two adjacent waveguides.

[0069] Figure 4 This is a schematic diagram of the structure of the microring provided in an embodiment of this disclosure. Figure 4 The microrings shown are racetrack-shaped microrings. See [link / reference]. Figure 4 The microring can be considered as being composed of two straight waveguide sections p1 and p2 and two curved waveguide sections p3 and p4. Specifically, the straight waveguide sections p1 and p2 can be coupled to different waveguides, and a second modulation unit can be provided on the curved waveguide section p3 or p4. This increases the coupling area between the microring and the waveguide, thereby improving the coupling coefficient and coupling efficiency. It should be noted that the microring in the embodiments of this disclosure can be approximately considered as being composed of straight waveguide sections and curved waveguide sections, and is not intended to limit the microring to be formed by splicing straight waveguide sections and curved waveguide sections. In fact, the microring involved in this disclosure can be formed integrally.

[0070] This disclosure provides a wide-tunable laser, including a first laser module, an external cavity module, and a second laser module connected in sequence. The end face of the first laser module away from the external cavity module has a first reflective film, and the end face of the second laser module away from the external cavity module has a second reflective film. The reflectivity of the first reflective film is greater than that of the second reflective film. The first laser module or the second laser module is used to generate an optical signal and inject it into the external cavity module. The external cavity module is used to narrow the linewidth of the optical signal and perform mode selection on the optical signal, transmitting the optical signal that meets the preset mode to the second laser module or the first laser module. The optical signal that meets the preset mode travels back and forth multiple times between the first reflective film, the external cavity module, and the second reflective film to form laser oscillation, and is output through the second reflective film. This embodiment integrates a first laser module, an external cavity module, and a second laser module. Different optical signals are generated and tuned using either the first or second laser module in different scenarios. This allows the tunable range of the laser provided in this embodiment to fully cover the tuning ranges of both the first and second laser modules, thus widening the laser's tuning range. Furthermore, the optical signals generated by either the first or second laser module can be tuned separately in different scenarios. Therefore, the increased tuning range does not affect the laser's tuning accuracy or tuning difficulty. The laser provided in this embodiment can also form a single-mode laser oscillation between the first reflective film, the external cavity module, and the second reflective film, and this oscillation is amplified by either the first or second laser module, enabling the output of a high-power, narrow-linewidth single-mode laser.

[0071] It should be understood that the phrase "an embodiment" or "one embodiment" throughout the specification means that a specific feature, structure, or characteristic related to the embodiment is included in at least one embodiment of this disclosure. Therefore, "in one embodiment" or "one embodiment" appearing throughout the specification does not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. It should be understood that in the various embodiments of this disclosure, the sequence numbers of the above-described processes do not imply a sequential order of execution; the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this disclosure. The sequence numbers of the above-described embodiments are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0072] The above description is merely a preferred embodiment of this disclosure and does not limit the patent scope of this disclosure. Any equivalent structural transformations made using the contents of this specification and drawings under the inventive concept of this disclosure, or direct / indirect applications in other related technical fields, are included within the patent protection scope of this disclosure.

Claims

1. A wide tuning laser, characterized by, The first laser module, the external cavity module and the second laser module are connected in sequence. The first laser module is provided with a first reflective film away from the end face of the external cavity module, and the second laser module is provided with a second reflective film away from the end face of the external cavity module; the reflectivity of the first reflective film is greater than the reflectivity of the second reflective film. The first laser module or the second laser module is used for generating an optical signal and injecting the optical signal into the external cavity module; wherein the first laser module is used for generating an optical signal with a first tunable waveband, and the second laser module is used for generating an optical signal with a second tunable waveband, and the first tunable waveband is different from the second tunable waveband. The external cavity module is used for narrowing the linewidth of the optical signal and selecting the mode of the optical signal, and transmitting the optical signal meeting a preset mode to the second laser module or the first laser module. The optical signal meeting the preset mode is transmitted between the first reflective film, the external cavity module and the second reflective film for multiple times to form laser oscillation, and is output through the second reflective film.

2. The wide tuning laser of claim 1, wherein, The reflection waveband of the first reflective film covers at least the first tunable waveband and the second tunable waveband, and the reflection waveband of the second reflective film covers at least the first tunable waveband and the second tunable waveband.

3. The wide tuning laser of claim 1, wherein, The external cavity module comprises at least three waveguides arranged along a first direction, and the extension direction of the waveguides intersects the first direction. A micro-ring is arranged between any adjacent two waveguides of the at least three waveguides.

4. The wide tuning laser of claim 3, wherein, The free spectral range of each micro-ring is different.

5. The widely tunable laser of claim 3, wherein, A first modulation unit is arranged on the first waveguide and the last waveguide, and the first modulation unit is a phase modulator.

6. The widely tunable laser of claim 3, wherein, A second modulation unit is arranged on at least one micro-ring, and the second modulation unit is a thermal modulator or an electro-optical modulator.

7. The wide tuning laser of claim 3, wherein, The micro-ring is a racetrack micro-ring, and the straight waveguide part of the racetrack micro-ring is coupled with the adjacent two waveguides.

8. The broad tuning laser of claim 1, wherein, The end face of the first laser module connected with the external cavity module is provided with a first anti-reflection film, and the end face of the second laser module connected with the external cavity module is provided with a second anti-reflection film.

9. The broad tuning laser of claim 1, wherein, Further comprising: A first coupling unit connected between the first laser module and the first end of the external cavity module, the first coupling unit is used for coupling the optical signal output by the first laser module to the first end of the external cavity module, or coupling the optical signal output by the first end of the external cavity module to the first laser module; A second coupling unit connected between the second laser module and the second end of the external cavity module, the second coupling unit is used for coupling the optical signal output by the second laser module to the second end of the external cavity module, or coupling the optical signal output by the second end of the external cavity module to the second laser module; the first end and the second end of the external cavity module are two end faces opposite to each other.

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