Device and method of integrated optical injection conical power amplifier

Abstract

The invention relates to the technical field of semiconductor light amplification, in particular to a device and method of an integrated light injection conical power amplifier. A semiconductor laser provides a seed light source for the conical power amplifier; the optical fiber collimator converts the seed light source into a space collimated light beam; the polarization direction of the space collimated light beam is adjusted to be the horizontal direction by the half-wave plate; the focusing lens focuses the space collimated light beam in the horizontal direction to the input end of the conical power amplifier; the conical power amplifier amplifies the output power of the focused beam and outputs an amplified beam; the output collimating lens preliminarily collimates the amplified light beam; the opto-isolator allows the amplified light beam to pass through and reduces subsequent return light. According to the device disclosed by the embodiment of the invention, the seed light is efficiently coupled into the optical fiber collimator, power amplification is realized in cooperation with the synergistic effect of subsequent optical elements, tedious matching of light beam directions is avoided, adjustment variables are reduced, and the seed light injection process is simpler, more convenient and more efficient.

Description

Technical Field

[0001] The present disclosure relates to the technical field of semiconductor optical amplification, and in particular to a device and method for an integrated optical injection tapered power amplifier. Background Art

[0002] In the field of weak magnetic field detection, narrow-linewidth, tunable semiconductor lasers, as the light source of optical magnetometers, are crucial for improving the sensitivity of weak magnetic field detection. However, the output optical power of narrow-linewidth tunable semiconductor laser chips is usually limited, requiring secondary amplification with semiconductor optical amplifiers (such as tapered power amplifiers).

[0003] In the conventional optical amplification process, the injection of a seed light source often requires multiple lenses for beam collimation, shaping, and polarization adjustment. The beam injection direction is then adjusted using a pair of adjustment mounts. This large number of adjustment variables and the large space required during the injection process lead to poor stability in the amplified output power. Therefore, how to address these issues during the injection process and improve the stability of the amplified output power has become a pressing issue. Summary of the Invention

[0004] In view of this, the present disclosure provides an apparatus and method for an integrated optical injection tapered power amplifier to solve the problems of large adjustment variables and large space occupied during the injection process, thereby improving the stability of the amplified output power.

[0005] The present disclosure provides an integrated light injection device for a tapered power amplifier, comprising: a laser, a fiber collimator, a half-wave plate, a focusing lens, a tapered power amplifier, an output collimating lens, and an optical isolator. The laser is a semiconductor laser and is used to provide a seed light source for the tapered power amplifier; the fiber collimator has a fiber interface at its rear end that matches the output end of the laser and is used to convert the seed light source into a spatially collimated light beam with adjustable direction; the half-wave plate is used to adjust the polarization direction of the spatially collimated light beam to a horizontal direction to match the polarization requirements of the tapered power amplifier; the focusing lens is used to focus the spatially collimated light beam at the input end of the tapered power amplifier; the tapered power amplifier is used to amplify the output power of the focused light beam and output the amplified light beam; the output collimating lens is used to perform preliminary collimation processing on the divergent amplified light beam; and the optical isolator is used to allow the amplified light beam to pass through and attenuate the return light propagating back to the tapered power amplifier.

[0006] In one possible implementation, the output end of the laser is connected to the optical fiber interface through a fiber coupler, and the optical fiber interface is connected to the output end of the optical fiber collimator through a polarization-maintaining fiber; the seed light source provided by the laser enters the optical fiber interface through the fiber coupler and is transmitted to the output end of the optical fiber collimator through the polarization-maintaining fiber.

[0007] In one possible implementation, the output end of the fiber collimator and the fiber interface provided at the rear end of the fiber collimator are connected by a polarization-maintaining fiber; the output end of the fiber collimator is composed of a glass ferrule, a glass sleeve and a fiber collimating lens, which is used to convert the seed light source transmitted through the polarization-maintaining fiber into a Gaussian collimated beam that meets preset conditions.

[0008] In one possible implementation, the fiber collimator, the half-wave plate, and the focusing lens are all mounted on a heat sink of the tapered power amplifier.

[0009] In one possible implementation, the half-wave plate, focusing lens, fiber collimating lens, output collimating lens, and the input and output ends of the tapered power amplifier are all coated with anti-reflection coatings to reduce light reflection losses on the surfaces of optical components and the ports of the tapered power amplifier. In one possible implementation, the apparatus further includes: a multi-dimensional adjustment mount for an optical fiber collimator, wherein: The multi-dimensional adjustment frame for the optical fiber collimator is composed of a six-dimensional adjustment frame and a combined bracket installed in conjunction with the optical fiber collimator. The six-dimensional adjustment frame is used to adjust the azimuth and tilt angle of the optical fiber collimator through the combined bracket.

[0010] In one possible implementation, the device further includes: a focusing lens plane adjustment device, wherein: the focusing lens plane adjustment device has a mounting slot for the focusing lens and is provided with several adjustment screws for controlling the front and rear position of the focusing lens and the mirror tilt angle.

[0011] The present disclosure also provides a method for integrated light injection into a tapered power amplifier, the method comprising: providing a seed light source for the tapered power amplifier through a laser; wherein the laser is a semiconductor laser; receiving the seed light source through a fiber collimator, converting the seed light source into a spatially collimated light beam, and injecting the spatially collimated light beam into a half-wave plate; wherein the tail of the fiber collimator is provided with a fiber interface that matches the fiber coupler at the output end of the laser; adjusting the polarization direction of the spatially collimated light beam to a horizontal direction through the half-wave plate, and injecting the adjusted light beam into a focusing lens; focusing the horizontal spatially collimated light beam onto the input end of the tapered power amplifier through the focusing lens; amplifying the output power of the focused light beam through the tapered power amplifier, and outputting the amplified light beam; collimating the divergent amplified light beam through the output collimating lens, and injecting the collimated amplified light beam into an optical isolator; allowing the collimated amplified light beam to pass through through the optical isolator, and attenuating the return light propagating back to the tapered power amplifier.

[0012] In one possible implementation, a seed light source is received through a fiber collimator, and the seed light source is converted into a spatially collimated beam, and the spatially collimated beam is injected into a half-wave plate, including: receiving the seed light source from the fiber coupler at the output end of the laser through the fiber interface at the rear end of the fiber collimator; wherein the output end of the laser is connected to the fiber interface through the fiber coupler, and the fiber interface is connected to the fiber collimator through a polarization-maintaining fiber; through the glass core, glass sleeve and fiber collimating lens at the output end of the fiber collimator, the seed light source transmitted by the polarization-maintaining fiber is converted into a Gaussian collimated beam that meets preset conditions; wherein the Gaussian collimated beam is a spatially collimated beam; and injecting the Gaussian collimated beam into the half-wave plate.

[0013] In one possible implementation, the method further includes: before converting the seed light source into a spatially collimated light beam through the fiber collimator, determining a fiber collimator assembly that matches the output beam diameter according to the wavelength of the seed light source, the focal length of the focusing lens, and the mode field diameter at the input end of the tapered power amplifier using the following formula:

[0014] in, is the output beam diameter, is the wavelength of the seed light source, is the focal length of the focusing lens, is the mode field diameter at the input of the tapered power amplifier.

[0015] By using the device and method for an integrated light injection tapered power amplifier according to the above-mentioned embodiment of the present disclosure, seed light is coupled into a polarization-maintaining fiber and then transmitted to the output end of a fiber collimator. In combination with the synergistic effect of subsequent optical elements, the tedious operation of adjusting the light beam injection direction through a pair of reflector adjustment mounts is avoided, the adjustment variables are reduced, and the seed light injection process is made simpler and more efficient.

[0016] In addition, the fiber collimator, half-wave plate, and focusing lens are integrated and installed on the heat sink of the tapered power amplifier, which greatly saves space and reduces the interference of external factors such as ambient temperature on various optical components. This helps to improve the stability of the amplified output power and overcomes the poor stability problem caused by the complex optical path of traditional solutions. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the specific embodiments of the present disclosure or the technical solutions in the related technologies, the following briefly introduces the drawings required for use in the specific embodiments or related technical descriptions. Obviously, the drawings described below are some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 11 is a schematic structural diagram of an integrated optical injection tapered power amplifier device provided by an embodiment of the present disclosure; Figure 2 This is a schematic diagram of the specific structure of an integrated light injection tapered power amplifier device provided by an embodiment of the present disclosure; Figure 3 1 is a detailed structural diagram of an integrated optical injection tapered power amplifier device provided by an embodiment of the present disclosure; Figure 4 It is a flow chart of a method for integrated light injection into a tapered power amplifier provided by an embodiment of the present disclosure. DETAILED DESCRIPTION

[0019] The rapid development of ultra-high-sensitivity atomic magnetometers has achieved the highest magnetic sensitivity in weak magnetic field measurements, offering significant advantages in quantum sensors and weak magnetic detection. In weak magnetic field detection, narrow-linewidth, tunable semiconductor lasers, used as the light source for optical magnetometers, can enhance detection sensitivity. However, the output power of these laser chips is limited, requiring secondary amplification by semiconductor optical amplifiers (SOAs).

[0020] Tapered power amplifiers (PAs) can achieve output powers of several watts. They consist of a ridge waveguide (a few microns wide, where the input light is guided) and a tapered structure (with increasing lateral dimensions but a constant height, where the seed light is amplified). Both the input and output ends are coated with anti-reflection (AR). Besides expensive commercial pre-aligned butterfly packages, commonly used C-mount PAs often suffer from the following issues: 1. When injecting seed light, it needs to be collimated, shaped, and polarized by a half-wave plate. Then, the beam direction is matched with the help of a double-mirror adjustment frame, and finally, it is focused and injected with a focusing lens (the injection port is only a few microns); 2. It is easily affected by the quality of the seed light beam, has large adjustment variables, occupies a large space, and the optical mechanical structure is affected by ambient temperature fluctuations, resulting in poor stability of the amplified output power.

[0021] To address the above-mentioned problems, various embodiments of the present disclosure provide an integrated light injection device for a tapered power amplifier, comprising: a laser, a fiber collimator, a half-wave plate, a focusing lens, a tapered power amplifier, an output collimating lens, and an optical isolator, wherein: the laser is a semiconductor laser, used to provide a seed light source for the tapered power amplifier; the fiber collimator has a fiber interface at its rear end that matches the output end of the laser, and is used to convert the seed light source into a spatially collimated light beam with adjustable direction; the half-wave plate is used to adjust the polarization direction of the spatially collimated light beam to a horizontal direction to match the polarization requirements of the tapered power amplifier; the focusing lens is used to focus the spatially collimated light beam at the input end of the tapered power amplifier; the tapered power amplifier is used to amplify the output power of the focused light beam and output an amplified light beam; the output collimating lens is used to perform preliminary collimation processing on the divergent amplified light beam; and the optical isolator is used to allow the amplified light beam to pass through and attenuate the return light propagating back to the tapered power amplifier.

[0022] To make the purpose, technical solutions, and advantages of the embodiments of the present disclosure more clear, the technical solutions in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments of the present disclosure, all other embodiments obtained by those skilled in the art without making creative efforts shall fall within the scope of protection of the present disclosure.

[0023] Please refer to Figure 1 , Figure 1 1 is a schematic diagram of the structure of an integrated light injection tapered power amplifier device provided by an embodiment of the present disclosure. The structure of the device may include: a laser 101, a fiber collimator 102, a half-wave plate 103, a focusing lens 104, a tapered power amplifier 105, an output collimating lens 106, and an optical isolator 107, wherein: The laser 101 is a semiconductor laser and is used to provide a seed light source for the tapered power amplifier 105 .

[0024] In this embodiment, the laser 101 uses a Bragg grating to form distributed feedback to achieve single longitudinal mode lasing, and is used to output laser light with a narrow linewidth and stable wavelength as a seed light source.

[0025] Preferably, the laser 101 is a distributed feedback semiconductor laser.

[0026] Here, the seed light source may refer to a low-power laser source provided by the laser 101 and waiting to be further amplified by the tapered power amplifier 105. For example, the output power of the seed laser may be in the milliwatt level, and after amplification by the tapered power amplifier 105, the output power may reach the watt level.

[0027] The tapered power amplifier 105 for amplifying the power of the seed light source is a semiconductor optical amplifier with a tapered output end. It can amplify the low-power seed light to a watt-level output power while maintaining the wavelength and polarization direction of the light beam.

[0028] Here, the tapered power amplifier 105 consists of a ridge waveguide region and a trapezoidal active region. The ridge waveguide region is located at the front end, with a waveguide width of only a few microns, which is used to guide and constrain the input seed light signal. The trapezoidal active region is located at the back end, with the waveguide width gradually increasing along the direction of light propagation, which is used to increase the amplification power.

[0029] The fiber collimator 102 has a fiber interface at its rear end that matches the output end of the laser 101 and is used to convert the seed light source into a spatially collimated beam with adjustable direction.

[0030] In this embodiment, the laser 101 couples the seed beam into the fiber core of the fiber collimator 102 through a fiber coupler. The fiber interface is connected to the output end of the fiber collimator 102 via a polarization-maintaining fiber. The polarization-maintaining fiber can maintain the polarization state of the seed beam stable during transmission.

[0031] Here, the optical fiber interface at the rear of the optical fiber collimator 102 is used to provide a physical connection interface with the polarization-maintaining optical fiber to ensure stable docking between the polarization-maintaining optical fiber and the optical fiber collimator 102, thereby realizing the physical transmission path of the seed light from the polarization-maintaining optical fiber to the optical fiber collimator 102.

[0032] Furthermore, the optical fiber collimating lens used by the optical fiber collimator 102 at least includes: a spherical lens, an aspherical lens or a gradient refractive index lens.

[0033] In this embodiment, the optical fiber collimating lens used in the optical fiber collimator 102 can be a spherical lens, an aspheric lens or a gradient refractive index lens; among them, the aspheric lens, through a special curved surface design, can eliminate spherical aberration and efficiently convert the divergent light output by the optical fiber into collimated light with extremely high parallelism; the internal refractive index of the gradient refractive index lens changes gradiently along the radial direction, and light beam collimation can be achieved without the need for complex curved surfaces.

[0034] The half wave plate 103 is used to adjust the polarization direction of the spatially collimated light beam to a horizontal direction to match the polarization requirement of the tapered power amplifier 105 .

[0035] In this embodiment, the half wave plate 103 is used to generate an optical path difference between two mutually perpendicular vibration components of the polarized light when the spatially collimated light beam is incident, thereby rotating and adjusting the polarization direction of the spatially collimated light beam to a horizontal direction.

[0036] Here, the internal waveguide structure of the tapered power amplifier 105 has strict requirements on the polarization direction of the incident light. When the incident light is in the horizontal direction, the maximum amplification efficiency can be achieved.

[0037] The focusing lens 104 is used to focus the horizontal spatial collimated light beam onto the input end of the tapered power amplifier 105 .

[0038] In this embodiment, the focusing lens 104 is specifically used to compress the size of the spatially collimated light beam in the horizontal direction through the refraction effect, so that the energy of the spatially collimated light beam is concentrated at the input end of the tapered power amplifier 105, thereby ensuring that the seed beam can be efficiently injected into the ridge waveguide region of the tapered power amplifier 105.

[0039] The tapered power amplifier 105 is used to amplify the output power of the focused light beam and output the amplified light beam.

[0040] The output collimating lens 106 is used to perform preliminary collimation processing on the divergent amplified light beam.

[0041] In this embodiment, the amplified light beam output by the tapered power amplifier 105 diverges, and the output collimating lens 106 needs to perform preliminary collimation on the divergent amplified light beam to adjust the X-axis light beam with a larger divergence angle in the amplified light beam to be less than or equal to 0 degrees.

[0042] The optical isolator 107 is used to allow the amplified light beam to pass through and attenuate the return light propagating back to the tapered power amplifier 105 .

[0043] In this embodiment, the optical isolator 107 is used to allow the amplified light beam to be transmitted in a forward direction with low loss, and to isolate most of the light transmitted in the reverse direction, thereby blocking the propagation path of the return light.

[0044] Here, placing the optical isolator 107 in the output optical path of the tapered power amplifier 105 can ensure stable operation of the amplifier.

[0045] Furthermore, the transmission path of the seed light source in the above device is: laser 101 → fiber collimator 102 → half wave plate 103 → focusing lens 104 → tapered power amplifier 105 → output collimating lens 106 → optical isolator 107 .

[0046] The apparatus and method for integrated light injection into a tapered power amplifier according to the above-described embodiments of the present disclosure couples the seed light from laser 101 into a polarization-maintaining fiber and transmits it to the output end of fiber collimator 102. This, in conjunction with the synergistic effects of subsequent optical components, avoids the tedious operation of beam direction matching using a reflector adjustment mount, reduces adjustment variables, and makes the seed light injection process simpler and more efficient. Optical isolator 107 effectively blocks reverse return light, preventing it from interfering with the operating state of tapered power amplifier 105 and reducing output power fluctuations. Furthermore, the polarization-maintaining fiber maintains polarization stability during transmission, ensuring the accuracy of subsequent polarization adjustment and further guaranteeing the stability of the amplification process.

[0047] In a possible implementation of the above embodiment, the output end of the laser 101 is connected to the optical fiber interface through a fiber coupler, and the optical fiber interface is connected to the output end of the optical fiber collimator 102 through a polarization-maintaining optical fiber; the seed light source provided by the laser 101 enters the optical fiber interface through the fiber coupler and is transmitted to the output end of the optical fiber collimator 102 through the polarization-maintaining optical fiber.

[0048] In this embodiment, the transmission path of the seed light source from the laser 101 to the fiber collimator 102 is: output end of the laser 101 → fiber coupler → fiber interface → polarization-maintaining fiber → output end of the fiber collimator 102 .

[0049] Specifically, the laser 101 serves as the emission source of the seed light source, and the seed light outputted is a low-power laser with a narrow linewidth and stable wavelength. A fiber coupler matching the fiber interface of the fiber collimator is provided at the output end of the laser 101 to ensure physical docking with the fiber collimator.

[0050] The fiber coupler provided at the output end of the laser 101 is used to achieve efficient coupling of the output light of the laser 101 and the fiber interface, and to guide the seed light source into the polarization-maintaining fiber to the maximum extent.

[0051] Here, by fine-tuning the alignment accuracy of the fiber coupler (such as axial position and angle), the fiber coupling efficiency can be optimized to ensure that the seed light source enters the polarization-maintaining fiber with minimal loss.

[0052] Furthermore, the optical fiber interface is physically connected to the output end of the optical fiber coupler, and the optical fiber interface is connected to the output end of the optical fiber collimator 102 through the polarization-maintaining optical fiber, forming a full-link polarization-stabilized transmission.

[0053] Through the device and method of the integrated light injection tapered power amplifier of the above-mentioned embodiment of the present disclosure, the output end of the laser 101 is provided with a fiber coupler that matches the fiber interface of the fiber collimator to ensure the stability of the physical docking. In combination with the fine-tuning function of the fiber coupler, the coupling efficiency can be significantly optimized and the power loss of the seed light when entering the fiber interface can be minimized, thereby improving the transmission efficiency of the seed light source. The fiber interface at the tail of the fiber collimator 102 transmits the coupled seed light through the polarization-maintaining fiber through the fiber coupler at the output end of the laser, reducing the complex mechanical alignment steps in the free-space optical path of the related technology. This structured docking method reduces the operational complexity when setting up the system and improves the stability and repeatability of the optical path.

[0054] In a possible implementation of the above embodiment, the output end of the fiber collimator 102 and the fiber interface provided at the rear end of the fiber collimator are connected by a polarization-maintaining fiber; the output end of the fiber collimator 102 is composed of a glass ferrule, a glass sleeve and a fiber collimating lens, which is used to convert the seed light source transmitted through the polarization-maintaining fiber into a Gaussian collimated beam that meets preset conditions.

[0055] In this embodiment, a fiber optic interface is provided at the tail end of the fiber optic collimator 102 serving as the input end, and an input path for the seed light source is formed by connecting the polarization-maintaining fiber and the fiber optic interface; the output end of the fiber optic collimator 102 is composed of a glass ferrule, a glass sleeve, and a fiber optic collimating lens, which is used to convert the seed light source into a Gaussian collimated beam that meets preset conditions.

[0056] Here, the Gaussian collimated light beam meeting the preset conditions may refer to a Gaussian collimated light having a shape close to a circle and a divergence angle close to zero.

[0057] Specifically, the polarization-maintaining fiber extends from the fiber interface to the interior of the fiber collimator 102 and directly interfaces with the glass ferrule, thereby maintaining a stable polarization state for the seed light source transmitted to the fiber collimator 102. The polarization-maintaining fiber is fixed with glue to prevent polarization disturbances caused by loose interfaces or mechanical stress, providing a stable input for subsequent collimation and polarization adjustment.

[0058] The glass ferrule can be made of high-precision ceramic or glass and has a central through-hole. The core end of the polarization-maintaining fiber is fixed within the through-hole to ensure that the center of the fiber's output light coincides with the ferrule's axis, serving as the reference point for the fiber's collimating lens. A glass sleeve can be placed over the glass ferrule to secure and protect it. Fine-tuning the ferrule's position within the sleeve further calibrates the relative position of the polarization-maintaining fiber and the fiber's collimating lens, thereby outputting a horizontal Gaussian collimated beam.

[0059] The apparatus and method for an integrated light-injection tapered power amplifier disclosed in the aforementioned embodiments of the present invention achieve a symmetrical Gaussian collimated beam with a minimal divergence angle, avoiding the beam distortion caused by multiple lens shaping in related technologies. This provides ideal incident light for subsequent polarization adjustment of half-wave plate 103 and precise focusing of focusing lens 104, reducing injection efficiency losses due to poor beam quality. The conversion of fiber light to spatially collimated light is directly achieved through fiber collimator 102, replacing the complex structure of multiple lens shaping and collimation, reducing system size and adjustment difficulty.

[0060] In a possible implementation of the above embodiment, please refer to Figure 1 ,like Figure 1 As shown, the structure of the device may further include: a heat sink 108 ; wherein the fiber collimator 102 , the half wave plate 103 and the focusing lens 104 are all mounted on the heat sink 108 of the tapered power amplifier 105 .

[0061] In this embodiment, the heat sink 108 may be a passive heat dissipation device, which is used to transfer the heat of the heat source to the heat sink body through contact with the heat source, and then dissipate the heat to the external environment through air convection, radiation or heat conduction.

[0062] Here, since the tapered power amplifier 105 generates a large amount of heat during operation, the tapered power amplifier 105 needs to be mounted on a heat sink to achieve heat dissipation.

[0063] Furthermore, the fiber collimator 102, half-wave plate 103 and focusing lens 104 are also installed on the heat sink 108 of the tapered power amplifier 105, which can realize the integration of the structure and thus improve the anti-disturbance capability; by using the heat sink 108 as an integration platform, the coordinate system can be unified, thereby facilitating the injection of the seed beam.

[0064] By using the device and method for integrated light injection into a tapered power amplifier according to the above-mentioned embodiment of the present disclosure, the fiber collimator 102, the half-wave plate 103, and the focusing lens 104 are integrated and mounted on the heat sink 108 of the tapered power amplifier 105, thereby significantly saving space and reducing the interference of external factors such as ambient temperature on the various optical components. This helps to improve the stability of the amplified output power and overcomes the problem of poor stability caused by the complex optical path of traditional solutions.

[0065] In one possible implementation of the above embodiment, the half-wave plate 103, the focusing lens 104, the fiber collimating lens, the output collimating lens 106, and the input and output ends of the tapered power amplifier 105 are all coated with anti-reflection coatings to reduce the reflection loss of light on the surfaces of each optical component and the port of the tapered power amplifier 105.

[0066] In this embodiment, the anti-reflection coating (AR coating) can be one or more thin films coated on the surface of the optical element. It uses the principle of destructive interference of light reflected from the upper and lower surfaces of the film to reduce the reflection of light at the interface, thereby improving the transmittance of light.

[0067] Specifically, the AR coating on the fiber collimating lens, the half-wave plate 103 and the focusing lens 104 is used to reduce the reflection of the seed light source on the lens surface; the AR coating on the tapered power amplifier 105 and the output collimating lens 106 is used to ensure that the tapered power amplifier 105 operates in a stable amplification state.

[0068] Through the device and method of the integrated light injection tapered power amplifier of the above embodiment of the present disclosure, the optical power utilization and stability of the system are directly improved by reducing reflection loss and suppressing interference through the AR coating.

[0069] In a possible implementation of the above embodiment, please refer to Figure 2 , Figure 2 1 is a schematic diagram of the specific structure of an integrated light injection tapered power amplifier device provided by an embodiment of the present disclosure. The structure of the device may also include: a fiber collimator multi-dimensional adjustment frame 109, a focusing lens plane adjustment device 110, wherein: The optical fiber collimator multi-dimensional adjustment frame 109 is composed of a six-dimensional adjustment frame and a combined bracket for mounting the optical fiber collimator 102. The six-dimensional adjustment frame is used to adjust the orientation and tilt angle of the optical fiber collimator 102 through the combined bracket. The focusing lens plane adjustment device 110 has a mounting slot for the focusing lens 104 and is provided with several adjustment screws for controlling the front and rear position of the focusing lens 104 and the tilt angle of the mirror surface.

[0070] In this embodiment, the six-dimensional adjustment frame can be composed of precision mechanical guide rails and fine-tuning knobs, which can realize translation adjustment along the X, Y, and Z axes and rotation adjustment around the X, Y, and Z axes, covering six degrees of freedom motion control.

[0071] Specifically, when the direction of the light emitted from the fiber collimator 102 needs to be adjusted, the fine-tuning knob of the six-dimensional adjustment frame is rotated to drive the combined bracket to drive the fiber collimator 102 to complete a slight change in the azimuth and tilt angle, thereby changing the emission direction of the Gaussian collimated light beam.

[0072] Here, in order to adapt to the external dimensions of the optical fiber collimator 102 , the optical fiber collimator 102 can be fixed to the bracket by bolts, and the other end of the bracket is rigidly connected to the six-dimensional adjustment frame.

[0073] Furthermore, the focusing lens plane adjustment device 110 is provided with a mounting slot for the focusing lens 104 that matches the outer diameter of the focusing lens 104 to ensure that the optical axis of the focusing lens 104 is consistent with the center of the slot after installation.

[0074] The focusing lens plane adjustment device 110 may include a front-back position adjustment slider and a mirror tilt adjustment knob for controlling the front-back position and mirror tilt angle of the focusing lens 104 .

[0075] The devices and methods for integrated light injection into a tapered power amplifier according to the above-mentioned embodiments of the present disclosure simplify the adjustment process through the step-by-step operation of collimator pointing adjustment and lens focus adjustment, allowing ordinary operators to complete optical path alignment in a short time. Both devices are compact and can be directly mounted on the heat sink 108 of the tapered power amplifier 105, forming a compact integrated system with other optical components, without taking up additional space and meeting the requirements of device miniaturization.

[0076] In a specific embodiment, please refer to Figure 3 , Figure 3 This is a detailed structural diagram of an integrated light injection tapered power amplifier device provided by an embodiment of the present disclosure. The device may include: a fiber collimator 102, a half-wave plate 103, a focusing lens 104, a tapered power amplifier 105, an output collimating lens 106, a heat sink 108 and a focusing lens plane adjustment device 110.

[0077] Among them, the fiber collimator 102 specifically includes a glass core, a glass sleeve and a fiber collimating lens; the focusing lens plane adjustment device 110 is provided with a mounting slot for the focusing lens 104; the fiber collimator 102, the half wave plate 103 and the focusing lens 104 are all installed on the heat sink 108 of the tapered power amplifier 105.

[0078] Please refer to Figure 4 , Figure 4 FIG. 1 is a flow chart of a method for integrated optical injection into a tapered power amplifier provided by an embodiment of the present disclosure. The flow of the method may include: Step S401 : providing a seed light source for the tapered power amplifier 105 via the laser 101 .

[0079] In this embodiment, the laser 101 is a distributed feedback semiconductor laser.

[0080] The seed light source is transmitted to the fiber collimator 102 via the polarization-maintaining fiber. The fiber collimator 102 is provided with a fiber interface at the tail end thereof that matches the fiber coupler at the output end of the laser 101 , and the fiber collimator 102 and the fiber interface are connected via the polarization-maintaining fiber.

[0081] In step S402 , the seed light source is received by the fiber collimator 102 , and the seed light source is converted into a spatially collimated light beam, and the spatially collimated light beam is emitted into the half-wave plate 103 .

[0082] In this embodiment, a fiber optic interface that matches the fiber optic coupler at the output end of the laser 101 is provided at the tail end of the fiber optic collimator 102 .

[0083] In step S403 , the polarization direction of the spatially collimated light beam is adjusted to a horizontal direction by the half-wave plate 103 , and the adjusted light beam is emitted into the focusing lens 104 .

[0084] In this embodiment, the polarization direction of the spatially collimated light beam is adjusted to a horizontal direction to match the polarization requirement of the tapered power amplifier 105 .

[0085] In step S404 , the horizontal spatial collimated light beam is focused on the input end of the tapered power amplifier 105 by the focusing lens 104 .

[0086] Step S405 : amplify the output power of the focused light beam by the tapered power amplifier 105 , and output the amplified light beam.

[0087] In this embodiment, the fiber collimator 102 , the half-wave plate 103 , and the focusing lens 104 are all mounted on a heat sink 108 of the tapered power amplifier 105 .

[0088] In step S406 , the divergent amplified light beam is collimated by the output collimating lens 106 , and the collimated amplified light beam is emitted into the optical isolator 107 .

[0089] In step S407 , the collimated amplified light beam is allowed to pass through the optical isolator 107 , and the return light propagating in the reverse direction to the tapered power amplifier 105 is attenuated.

[0090] In this embodiment, the process of the above method may specifically include: providing a seed light source for the tapered power amplifier 105 through a distributed feedback semiconductor laser 101, the seed light source is transmitted to the output end of the fiber collimator 102 through a polarization-maintaining fiber, the rear end of the fiber collimator 102 is provided with a fiber interface that matches the fiber coupler at the output end of the laser 101, and the output end of the fiber collimator 102 and the fiber interface are connected by a polarization-maintaining fiber; The seed light source is received by the fiber collimator 102 and converted into a Gaussian collimated beam with a shape close to a circle and a divergence angle close to zero. The orientation and tilt angle of the fiber collimator 102 are adjusted by the fiber collimator multi-dimensional adjustment frame 109 to control the beam direction; The polarization direction of the Gaussian collimated beam is adjusted to the horizontal direction by the half-wave plate 103 to match the polarization requirement of the tapered power amplifier 105; A horizontally polarized Gaussian collimated light beam is focused onto the light injection port of a tapered power amplifier 105 by a focusing lens 104 coated with an anti-reflection coating and controlled by a focusing lens plane adjustment device 110. Both the input and output ends of the tapered power amplifier 105 are coated with an anti-reflection coating. The injected seed light is amplified by the tapered power amplifier 105 to output an amplified light beam, wherein the fiber collimator 102, the half-wave plate 103, and the focusing lens 104 are all mounted on the heat sink 108 of the tapered power amplifier 105 to achieve integrated operation; The amplified light beam is initially collimated by the output collimating lens 106 so that the X-axis light beam divergence angle is adjusted to be no greater than 0 degrees; The optical isolator 107 allows the amplified light beam to pass through and reduces the impact of subsequent return light on the tapered power amplifier 105.

[0091] In one possible implementation, a seed light source is received by a fiber collimator 102, and the seed light source is converted into a spatially collimated light beam, and the spatially collimated light beam is injected into a half-wave plate 103, including: The seed light source is received from the fiber coupler at the output end of the laser 101 through the fiber interface at the tail end of the fiber collimator 102; wherein the output end of the laser is connected to the fiber interface through the fiber coupler and transmitted to the output end of the fiber collimator through the polarization-maintaining fiber; The glass ferrule, glass sleeve and fiber collimating lens at the output end of the fiber collimator 102 are combined to convert the seed light source transmitted by the polarization-maintaining fiber into a Gaussian collimated beam that meets preset conditions; wherein the Gaussian collimated beam is a spatially collimated beam; The Gaussian collimated beam is injected into the half wave plate 103 .

[0092] In this embodiment, a fastening screw or a buckle can be used to fix the interface to form a rigid connection, thereby preventing the polarization-maintaining optical fiber from loosening in a vibrating environment and causing the optical axis to shift.

[0093] Furthermore, after the seed light source output by the laser 101 enters the polarization-maintaining fiber, the polarization state of the seed light source is maintained stable by the internal stress region of the polarization-maintaining fiber, thereby suppressing the influence of external interference on the polarization direction.

[0094] Insert the core end of the polarization-maintaining fiber into the central microhole of the glass ferrule, ensuring that the fiber core and the ferrule axis coincide with each other, and insert the glass ferrule with the optical fiber into the central hole of the glass sleeve. Adjust the position of the ferrule in the sleeve through the fine-tuning mechanism so that the center of the optical fiber output light coincides with the sleeve axis.

[0095] Furthermore, when the seed light is emitted from the end face of the glass ferrule, it is incident on the fiber optic collimating lens, and the divergent light is refracted by the special curved surface of the fiber optic collimating lens, eliminating spherical aberration, and the light beam wavefront is converted into a plane wave, forming a Gaussian collimated light beam with extremely high parallelism, and the Gaussian collimated light beam is emitted into the half wave plate 103.

[0096] In a possible implementation of the above embodiment, the method further includes: Before converting the seed light source into a spatially collimated beam through a fiber collimator, the fiber collimator assembly that matches the output beam diameter is determined using the following formula based on the seed light source wavelength, the focal length of the focusing lens, and the mode field diameter at the input end of the tapered power amplifier:

[0097] in, is the output beam diameter, is the wavelength of the seed light source, is the focal length of the focusing lens, is the mode field diameter at the input of the tapered power amplifier.

[0098] Although the embodiments of the present disclosure have been described with reference to the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present disclosure, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. An integrated light injection tapered power amplifier device, characterized in that: The device includes: Laser, fiber collimator, half wave plate, focusing lens, tapered power amplifier, output collimating lens and optical isolator, including: The laser is a semiconductor laser, used to provide a seed light source for the tapered power amplifier; The fiber collimator has a fiber interface at its rear end that matches the output end of the laser and is used to convert the seed light source into a spatially collimated beam with adjustable direction; The half-wave plate is used to adjust the polarization direction of the spatially collimated light beam to a horizontal direction to match the polarization requirement of the tapered power amplifier; The focusing lens is used to focus the spatially collimated light beam onto the input end of the tapered power amplifier; The tapered power amplifier is used to amplify the output power of the focused light beam and output an amplified light beam; The output collimating lens is used to perform preliminary collimation processing on the divergent amplified light beam; The optical isolator is used to allow the amplified light beam to pass through and attenuate the return light propagating back to the tapered power amplifier.

2. The device according to claim 1, characterized in that The output end of the laser is connected to the optical fiber interface through a fiber coupler, and the optical fiber interface is connected to the output end of the optical fiber collimator through a polarization-maintaining optical fiber; the seed light source provided by the laser enters the optical fiber interface through the fiber coupler and is transmitted to the output end of the optical fiber collimator through the polarization-maintaining optical fiber.

3. The device according to claim 2, characterized in that The output end of the fiber collimator and the fiber interface provided at the tail of the fiber collimator are connected through the polarization-maintaining fiber; the output end of the fiber collimator is composed of a glass ferrule, a glass sleeve and a fiber collimating lens, which is used to convert the seed light source transmitted through the polarization-maintaining fiber into a Gaussian collimated beam that meets preset conditions.

4. The device according to claim 1, characterized in that The optical fiber collimator, the half-wave plate and the focusing lens are all mounted on a heat sink of the tapered power amplifier.

5. The device according to claim 1, characterized in that The half-wave plate, focusing lens, fiber collimating lens, output collimating lens and the input and output ends of the tapered power amplifier are all coated with anti-reflection coatings to reduce the reflection loss of light on the surface of optical components and the port of the tapered power amplifier.

6. The device according to any one of claims 1 to 5, characterized in that The device further comprises: a multi-dimensional adjustment frame for an optical fiber collimator, wherein: The fiber collimator multi-dimensional adjustment frame is composed of a six-dimensional adjustment frame and a combined bracket installed in conjunction with the fiber collimator. The six-dimensional adjustment frame is used to adjust the orientation and tilt angle of the fiber collimator through the combined bracket.

7. The device according to claim 6, characterized in that The device further comprises: a focusing lens plane adjustment device, wherein: The focusing lens plane adjustment device has a mounting slot for the focusing lens and is provided with several adjustment screws for controlling the front and rear positions of the focusing lens and the tilt angle of the mirror surface.

8. A method for integrating light injection into a tapered power amplifier, characterized in that: The method comprises: Providing a seed light source for the tapered power amplifier through a laser; wherein the laser is a semiconductor laser; The seed light source is received through a fiber collimator, and the seed light source is converted into a spatial collimated beam, and the spatial collimated beam is injected into a half-wave plate; wherein the tail of the fiber collimator is provided with a fiber interface that matches the output end fiber coupler of the laser; Adjusting the polarization direction of the spatially collimated light beam to a horizontal direction through the half-wave plate, and injecting the adjusted light beam into a focusing lens; Focusing the horizontal spatial collimated light beam onto the input end of the tapered power amplifier through the focusing lens; amplifying the output power of the focused light beam by the tapered power amplifier and outputting the amplified light beam; collimating the divergent amplified light beam through an output collimating lens, and injecting the collimated amplified light beam into an optical isolator; The collimated amplified light beam is allowed to pass through the optical isolator, and the return light propagating back to the tapered power amplifier is attenuated.

9. The method according to claim 8, characterized in that The step of receiving the seed light source through a fiber collimator, converting the seed light source into a spatial collimated light beam, and injecting the spatial collimated light beam into a half-wave plate comprises: The seed light source is received from the fiber coupler at the output end of the laser through the fiber interface at the tail end of the fiber collimator; wherein the output end of the laser is connected to the fiber interface through the fiber coupler, and the fiber interface is connected to the fiber collimator through a polarization-maintaining fiber; The seed light source transmitted by the polarization-maintaining optical fiber is converted into a Gaussian collimated beam that meets preset conditions through the glass ferrule, glass sleeve and optical fiber collimating lens at the output end of the optical fiber collimator; wherein the Gaussian collimated beam is a spatially collimated beam; The Gaussian collimated beam is injected into a half-wave plate.

10. The method according to any one of claims 8 to 9, characterized in that The method further comprises: Before converting the seed light source into a spatially collimated beam through a fiber collimator, the fiber collimator assembly that matches the output beam diameter is determined using the following formula based on the seed light source wavelength, the focal length of the focusing lens, and the mode field diameter at the input end of the tapered power amplifier: in, is the output beam diameter, is the wavelength of the seed light source, is the focal length of the focusing lens, is the mode field diameter of the input end of the tapered power amplifier.

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