Miniaturized multifunctional laser module and light path control method thereof

Abstract

The invention belongs to the technical field of photoelectricity, and relates to a miniaturized multifunctional laser module and a light path control method thereof, and the structure of the miniaturized multifunctional laser module sequentially comprises a laser module which comprises a laser and a light beam shaping device along the same optical axis direction; the optical control module comprises a polarization splitting prism and a spectroscope; the light path protection and adjustment module comprises a Faraday isolator, a high-speed shutter and an attenuation wheel; and the optical fiber coupling module comprises a collimating lens, a precise adjustment platform and a single-mode polarization maintaining optical fiber, the laser generates a light beam, and after light beam shaping, polarization adjustment, 99: 1 light splitting and protection adjustment, the optical fiber coupling module outputs a stable optical fiber signal. The technical problems that in the prior art, a laser is poor in polarization control and power stability, low in high-speed switch response speed and high in spectrum switching function cost are solved, polarization adjustment, light splitting, protection adjustment and efficient optical fiber coupling functions are achieved in the same light path after light beams are generated, and the laser is suitable for various high-precision optical application scenes.

Description

Technical Field

[0001] The present invention belongs to the field of optoelectronic technology, and in particular, relates to a miniaturized multifunctional laser module and an optical path control method thereof. Background Art

[0002] With the rapid development of optoelectronic technology, laser technology has been widely used in many fields, and the requirements for laser luminescence performance are also increasing. Under the current technical background, lasers and their modules are widely used in high-precision scenarios such as angle measurement, optical surface detection, control, chip detection, ion counting, spectral analysis and DNA molecular sequencing. These application scenarios have put forward higher requirements for lasers, and laser technology is developing towards high quality, high stability, single polarization, low power consumption, low noise and small size.

[0003] However, the existing laser technology still has many shortcomings, which are mainly reflected in the following aspects:

[0004] 1. Polarization control and power stability issues: Currently, laser systems usually use external polarization control modules and independent power stability control modules, such as through polarizers, wave plates or polarization control circuits. This discrete design requires additional optical elements or electronic components, resulting in a complex system structure, larger volume, and increased overall power consumption. In addition, the assembly accuracy of these external modules has an impact on laser performance. A slight deviation may lead to a decrease in polarization ratio or unstable power, especially in environments with large vibrations or temperature changes.

[0005] 2. Response speed and accuracy issues of power regulation and high-speed switching: The power regulation and high-speed switching functions of lasers are usually achieved through electro-optic modulators or mechanical shutters. The regulation speed of these traditional components is limited by the drive circuit and mechanical inertia. For example, the common mechanical shutter response time is several milliseconds, which is difficult to meet the high dynamic range applications that require sub-microsecond regulation. In addition, due to the nonlinear characteristics of the electronic drive circuit and the physical limitations of the components, the control accuracy is usually not high, resulting in power fluctuations or instability during fast switching.

[0006] 3. Stability and cost issues of spectral half-width switching function: Existing technologies usually achieve spectral half-width switching through tunable gratings, filters or tunable laser cavity structures. These structures rely on high-precision optical component positioning and complex mechanical adjustments, and are extremely sensitive to environmental changes (such as temperature and vibration). Especially in multi-band switching applications, mechanical wear of components and reduced adjustment accuracy may lead to degradation of spectral performance. In addition, such designs are usually costly and have complex production processes, making them difficult to promote on a large scale.

[0007] The above technical deficiencies have severely limited the further application of lasers in the field of high-precision measurement and analysis. For example, in DNA sequencing or spectral analysis scenarios, the response speed, stability and spectrum switching capabilities of existing laser technologies are difficult to meet complex operational requirements. Therefore, developing a high-performance, multifunctional integrated laser to overcome the above technical problems has become a key direction for current research and industrial applications. Summary of the invention

[0008] In view of the defects in the prior art, the present invention proposes a miniaturized multifunctional laser module and its optical path control method. The laser module combines innovative structural design with conventional semiconductor laser packaging technology to successfully achieve multiple functions such as polarization control, power stabilization, power attenuation, high-speed switching, and spectral half-maximum full width switching. Compared with the shortcomings of traditional laser modules such as single function and unadjustable spectral half-maximum full width, the present invention provides an integrated, high-performance solution, improves the applicability and reliability of lasers, and provides new technical support for the field of precision measurement and analysis.

[0009] On the one hand, the present invention provides a miniaturized multifunctional laser module, the structure of which includes in sequence along the same optical axis:

[0010] A laser module, including a laser and a beam shaping device;

[0011] An optical control module, comprising a polarization beam splitter prism and a beam splitter; wherein the polarization beam splitter prism is used to adjust the polarization state of the laser beam, and the beam splitter is used to split the beam in a ratio of 99:1;

[0012] Optical path protection and adjustment module, including Faraday isolator, high-speed shutter and attenuation wheel;

[0013] Fiber coupling module, including collimating lens, precision adjustment platform and single-mode polarization-maintaining fiber;

[0014] The laser is used to generate a light beam, which is shaped by a beam shaping device and transmitted to the optical control module; the polarization beam splitter in the optical control module adjusts the light beam into a highly polarized light beam, and transmits the highly polarized light beam to the beam splitter; the beam splitter splits the highly polarized light beam in a ratio of 99:1, wherein 99% of the main light beam is transmitted to the optical path protection and adjustment module, and 1% of the feedback light beam is introduced into the feedback control module for power monitoring; the optical path protection and adjustment module is used to protect and adjust the main light beam, wherein the main light beam passes through the Faraday isolator, the high-speed shutter and the attenuation wheel in sequence, and is transmitted to the optical fiber coupling module; the optical fiber coupling module collimates and adjusts the main light beam through a collimating lens, and finally couples it into the single-mode polarization-maintaining optical fiber through the precision adjustment platform to achieve stable optical fiber output.

[0015] In a preferred implementation, further, the laser module is configured to support two spectral full width at half maximum specifications.

[0016] In a preferred implementation, the laser module further includes a semiconductor refrigerator, which is used to adjust the operating temperature of the laser module and control the temperature within a preset range.

[0017] In a preferred implementation, further, the beam shaping device includes a collimating lens, a beam expander and a converging lens, which are configured to shape the divergent laser beam to adjust it into a Gaussian beam that is approximately circular; the semiconductor refrigerator is configured to monitor the operating temperature of the laser module in real time, and accurately adjust the temperature through a temperature control circuit to ensure the spectral output stability of the laser light source.

[0018] In a preferred implementation, further, the feedback control module includes a light detector and a negative feedback circuit, wherein the light detector is used to detect a power signal of a feedback beam of the spectroscope, and the negative feedback circuit adjusts the output power of the laser module according to the power signal.

[0019] In a preferred implementation, further, the Faraday isolator in the optical path protection and adjustment module is used to isolate the back-reflected light to prevent it from returning to the laser light source; the high-speed shutter is used to achieve rapid switching of the optical path; and the attenuation wheel is used to achieve fixed-rate attenuation of multiple levels of optical power.

[0020] In a preferred implementation, further, the collimating lens in the fiber coupling module is configured to optimize the collimation of the light beam; and the precision adjustment platform is configured to efficiently couple the light beam to the single-mode polarization-maintaining fiber.

[0021] In a preferred implementation, further, the single-mode polarization-maintaining optical fiber is configured to output a light beam having stable polarization characteristics.

[0022] On the other hand, the present invention also provides a light path control method for a miniaturized multifunctional laser module based on any one of the above, the method comprising:

[0023] Step 1: Start the laser light source, the light beam output by the laser light source passes through a collimating lens, a beam expander and a converging lens in sequence, the divergence angle, diameter and shape of the light beam are optimized to shape the light beam into a Gaussian beam that is approximately circular, and the operating temperature of the laser module is adjusted by a semiconductor cooler to control the temperature within a preset range;

[0024] Step 2: passing the shaped light beam to a polarization beam splitter and a beam splitter in the same optical path, wherein the polarization beam splitter is configured to transmit P polarized light and reflect S polarized light by adjusting the alignment direction of the incident angle of the light beam with the optical axis, thereby achieving a polarization extinction ratio of ≥100:1;

[0025] Step 3: The highly polarized light beam transmitted through the polarization beam splitter prism directly enters the beam splitter, which is configured to split the light beam in a ratio of 99:1 in the same optical path, 99% of the light beam is transmitted to the optical path protection and adjustment module of the downstream main optical path, and 1% of the light beam is used as a feedback beam to enter the optical detector for real-time detection of optical power;

[0026] Step 4: The light beam in the main optical path is transmitted to the Faraday isolator, the high-speed shutter and the attenuation wheel in the optical path protection and adjustment module in sequence;

[0027] Step 5: The main beam is optimized for divergence angle through the collimating lens in the fiber coupling module, and the beam is efficiently coupled to the single-mode polarization-maintaining fiber using the precision adjustment platform in the fiber collimating coupler. The polarization characteristics of the beam are output through the single-mode polarization-maintaining fiber.

[0028] In a preferred implementation, further, the polarization state of the light beam is monitored in real time by a polarization measuring device, and the positional relationship between the laser module and the polarization beam splitter prism is locked when the polarization extinction ratio of the light transmitted by the polarization beam splitter prism reaches greater than 100:1.

[0029] The beneficial effects of the present invention are:

[0030] First, the miniaturized multifunctional laser module of the present invention realizes the functions of beam generation, polarization adjustment, splitting, protection adjustment and efficient fiber coupling in the same optical axis direction by integrating the laser module, optical control module, optical path protection and adjustment module and optical fiber coupling module, and has the advantages of compact structure, flexible operation and stable performance; the power is accurately monitored through the 99:1 splitting ratio, and the optical path safety and stable output are ensured by combining the Faraday isolator, high-speed shutter and attenuation wheel. At the same time, high-quality and high-polarization fiber output is realized through the single-mode polarization-maintaining optical fiber, which is suitable for a variety of high-precision optical application scenarios.

[0031] Second, in the preferred implementation, the laser module of the present invention supports the design of two spectral half-width specifications, giving the system higher flexibility and adaptability, enabling it to meet the specific requirements of spectral width in different application scenarios; whether it is a narrow spectrum application with high resolution requirements or a wide spectrum application with high energy output requirements, the module can provide optimized performance.

[0032] Third, in the preferred implementation, the beam shaping device of the present invention shapes the divergent laser beam through a combination of a collimating lens, a beam expander and a converging lens, optimizing it into a nearly circular Gaussian beam, thereby improving the beam quality and adaptability; the semiconductor refrigerator ensures the spectral output stability of the light source by real-time monitoring and precise adjustment of the operating temperature of the laser module.

[0033] Fourth, in the preferred implementation, the laser module of the present invention realizes accurate monitoring and real-time adjustment of laser power through the feedback control module to ensure stable output power; the Faraday isolator, high-speed shutter and attenuation wheel in the optical path protection and adjustment module respectively provide reflection isolation, fast switching and precise power control functions, effectively improving the safety and adaptability of the system; the fiber coupling module realizes efficient and stable fiber coupling through the optimized collimating lens and precision adjustment platform; the application of single-mode polarization-maintaining fiber further ensures the polarization stability of the output beam.

[0034] Fifth, the optical path control method of the present invention shapes the optical beam into a nearly circular Gaussian beam by accurately optimizing the divergence angle, diameter and shape of the optical beam, and simultaneously uses a polarization beam splitter prism and a beam splitter to achieve high polarization characteristics and precise beam splitting, ensuring a polarization extinction ratio ≥ 100:1 and efficient distribution of the beam energy; by adjusting the optical power through real-time detection and feedback, the stability and reliability of the system are improved; combined with the multiple control methods of the optical path protection module, optical path interference and power fluctuations are effectively avoided; and finally, efficient coupling of the optical beam and optimization of the polarization characteristics are achieved through precise adjustment, ensuring the high quality and stability of the output beam.

[0035] Sixth, in a preferred implementation, the present invention monitors the polarization state of the light beam in real time through a polarization measurement device, and locks the positional relationship between the laser module and the polarization beam splitter prism when the polarization extinction ratio of the light transmitted by the polarization beam splitter prism reaches greater than 100:1, thereby effectively ensuring the high polarization extinction ratio stability of the system, improving the accuracy and consistency of the polarization characteristics of the light beam, and avoiding the degradation of polarization performance due to position offset. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 is a schematic diagram of a miniaturized multifunctional laser module according to an embodiment of the present invention;

[0037] Figure 2 is a schematic diagram of a beam transmission path in a laser module of an embodiment of the present invention;

[0038] Figure 3 is a schematic diagram of a light beam transmission path in an optical control module according to an embodiment of the present invention;

[0039] Figure 4 is a schematic diagram of a light beam transmission path in an optical path protection and adjustment module of an embodiment of the present invention;

[0040] Figure 5 is a schematic diagram of a light beam transmission path in a fiber coupling module according to an embodiment of the present invention;

[0041] Figure 6 It is a flow chart of the optical path control method of the miniaturized multifunctional laser module according to an embodiment of the present invention. DETAILED DESCRIPTION

[0042] In order to enable those skilled in the art to better understand the technical solution of the present application, the present application will be further described in detail below with reference to the accompanying drawings and embodiments.

[0043] In the description of this application, the terms "first", "second", and "third" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance; the term "plurality" refers to two or more, unless otherwise expressly defined. Terms such as "installed", "connected", "connected", and "fixed" should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; "connected" can be a direct connection or an indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0044] In the description of the present application, it should be understood that the directions or positional relationships indicated by the terms "up", "down", "left", "right", "front", "back", etc. are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or unit referred to must have a specific direction, be constructed and operated in a specific orientation, and therefore, should not be understood as a limitation on the present application.

[0045] In the description of this specification, the description of the terms "one embodiment / method", "some embodiments / methods", "specific embodiments / methods", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment / method or example are included in at least one embodiment / method or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment / method or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments / methods or examples in a suitable manner.

[0046] As the instruction manual Figure 1The present invention describes a miniaturized multifunctional laser module, whose structure includes a laser module, an optical control module, an optical path protection and adjustment module, and an optical fiber coupling module in sequence along the same optical axis. Through the efficient integration of each module and the optimized transmission of the optical path, multifunctional designs such as polarization control, power stabilization, power attenuation, high-speed switching, and spectral half-maximum full width switching are realized to meet the needs of various precision application scenarios.

[0047] Among them, the laser module includes a laser light source (such as a superluminescent diode SLD or a semiconductor laser LD), a beam shaping device and a semiconductor refrigerator (TEC). The laser light source generates a laser with a central wavelength of 852nm, where the spectrum full width at half maximum (FWHM) is 5nm and 10nm. Light sources with different spectral widths can be selected according to specific applications to achieve a spectrum switching function. The beam shaping device is used to shape the divergent laser beam. Through compression, expansion or convergence operations, the beam is adjusted to a nearly circular Gaussian beam to improve the uniformity and quality of the beam. The semiconductor refrigerator (TEC) works with the thermistor and temperature control circuit to monitor the operating temperature of the laser module in real time, ensure that the light source operates within the optimal temperature range, reduce thermal drift, and enhance the stability of laser power and spectral output.

[0048] As the instruction manual Figure 2 In the laser module, the laser output beam is shaped by the beam shaping device and transmitted to the optical control module through the beam shaping device, providing high-quality input light source for subsequent functions to directly enter the downstream optical control module. Through modular design, the spectrum switching function and beam shaping function are integrated into the laser module, and the temperature control function of the semiconductor cooler (TEC) is combined to improve the stability and adaptability of the light source.

[0049] The number of laser modules is ≥ 1. When there is 1 laser module, only one laser module is used as the light source in the system. The optical path design is simple, the structure is compact, and it is convenient for optical alignment and modular packaging. It can be applied to scenarios with strict requirements for single-wavelength lasers, such as high-precision interferometry, displacement detection, and single-frequency spectral analysis. Since only one laser module is used, the system volume and power consumption are significantly reduced, which is suitable for handheld devices or small optical systems. It can be used for laboratory calibration or as a reference light source to provide stable laser output for other devices.

[0050] When there are multiple laser modules, the system contains multiple laser modules, which can output multiple light beams simultaneously or switch them. The laser modules can work independently, or the light beams can be combined through optical elements (such as beam splitters or fiber couplers). It can be used to support the simultaneous output or rapid switching of multiple wavelength light sources, and is suitable for scenarios that require multi-wavelength lasers, such as fluorescence spectroscopy and biological imaging. The light beams of multiple laser modules are synthesized to increase the output power for laser processing, welding or material surface treatment. Light beams of different wavelengths are used in multi-mode interference experiments to enhance the measurement capabilities of the system. In addition, in industrial and medical applications, the reliability of the system is improved through the redundant design of multiple laser modules.

[0051] The optical control module includes a polarization beam splitter (PBS) and a beam splitter (BS). The polarization beam splitter (PBS) is used to adjust the polarization state of the laser beam, eliminate unnecessary polarization components, and make the polarization extinction ratio of the beam reach a high performance index greater than 100:1. The polarization beam splitter (PBS) improves the consistency and stability of the light beam, and is particularly suitable for precision measurement scenarios with high polarization requirements. The beam splitter (BS) is used to split the power of the light beam at a ratio of 99:1. 99% of the main light beam enters the main light path for further transmission, and 1% of the feedback light beam is introduced into the feedback control module for real-time power monitoring. The precise splitting function of the beam splitter provides reliable guarantee for the coordinated operation of the main light path and feedback control.

[0052] As the instruction manual Figure 3 , the highly polarized light beam output by the polarization beam splitter (PBS) enters the beam splitter (BS); the beam splitter divides the light beam into two parts: the main light beam (99% power) is transmitted to the optical path protection and adjustment module. The feedback light beam (1% power) enters the feedback control module, which detects the optical power. The optical control module closely combines the polarization control and power splitting functions, reduces the number of optical path components, and realizes efficient splitting and real-time feedback control, simplifying the structural design.

[0053] In the implementation of the present application, the feedback control module adopts a photodetector (PD), which is used to detect the power of the light beam after splitting and adjust the output power of the laser through a negative feedback circuit to ensure the stability of the light power.

[0054] The optical path protection and adjustment module includes a Faraday isolator, a high-speed shutter, and an attenuation wheel. The Faraday isolator is used to prevent the back-reflected light of the downstream optical path from returning to the laser light source, avoiding mode hopping, amplitude fluctuation or frequency shift caused by reflected light, and ensuring the stability and safety of the laser. The high-speed shutter uses a voltage-driven mechanical switch to achieve sub-microsecond optical path fast switching function, which can meet the strict requirements of high dynamic range application scenarios on response speed. Its response speed can reach sub-microsecond level, meeting the needs of high dynamic range switching. The attenuation wheel is used to provide multiple fixed-rate optical power attenuation functions. Users can choose the appropriate power output according to their needs to ensure the adaptability of the laser in different scenarios.

[0055] As the instruction manual Figure 4 In the optical path protection and adjustment module, the main optical path beam from the beam splitter passes through the Faraday isolator (isolates back-reflected light), high-speed shutter (realizes fast switching), attenuation wheel (adjusts optical power) in turn, and is transmitted to the fiber coupling module. The optical path protection and adjustment module integrates optical path protection, high-speed switching and power adjustment functions through modular design, which not only improves the safety of optical path operation, but also enhances the flexibility of laser power adjustment.

[0056] The fiber coupling module includes a collimating lens and a single-mode polarization-maintaining fiber. The collimating lens is used to adjust the divergence angle of the spatial light beam, optimize the collimation of the light beam, and ensure that the light beam can be efficiently coupled into the optical fiber. The single-mode polarization-maintaining fiber is used to maintain the polarization characteristics of the optical fiber output light beam, ensure the stability and consistency of the polarized light beam, and improve the coupling efficiency of the optical fiber and the quality of optical path transmission.

[0057] As the instruction manual Figure 5 In the fiber coupling module, the light beam is output from the attenuation wheel and enters the collimating lens. After adjustment, it is finally coupled into the single-mode polarization-maintaining fiber to achieve stable fiber output.

[0058] It should be noted that the output beam of the laser module is non-polarized light, with a certain spatial divergence angle and an uneven polarization state. After passing through the beam shaping device, the beam is adjusted to a Gaussian beam that is approximately circular, but its polarization state still needs to be optimized. A polarization beam splitter is an optical element that can separate polarized beams. PBS depends on the incident angle of the beam and the optical crystal and the polarization direction of the beam to achieve the separation of P-polarized light and S-polarized light: P-polarized light is polarized light parallel to the incident plane of the beam, which can pass through the polarization beam splitter (PBS); S-polarized light is polarized light perpendicular to the incident plane of the beam, which can be reflected by the polarization beam splitter (PBS). The polarization control of existing lasers usually relies on external polarizers or wave plates, which are limited by component accuracy and beam characteristics, and cannot achieve a high polarization extinction ratio. In order to solve this problem, the present application achieves a polarization extinction ratio greater than 100:1 in the optical path design by adjusting the relative position of the laser module and the polarization beam splitter (PBS).

[0059] The core principle of the relative position adjustment between the laser module and the polarization beam splitter (PBS) of this application is that the output beam direction and polarization state of the laser module must be strictly aligned with the optical axis of the PBS after adjustment. By precisely controlling the relative position and angle between the laser module and the PBS, the incident direction of the light beam is optimized to be consistent with the optical axis direction of the PBS crystal, thereby achieving complete separation of S-polarized light. The specific process includes:

[0060] S1: Initial positioning: The laser module and PBS are initially aligned on the optical path to ensure that the laser output beam can completely enter the effective working area of ​​PBS.

[0061] S2: Position fine-tuning: Fine-tune the spatial position of the laser module through a precision optical adjustment device (such as an XYZ three-dimensional fine-tuning platform). Adjust the translation position of the laser along the X-axis direction to ensure that the center of the beam is consistent with the optical axis of the PBS. Adjust the height of the laser along the Y-axis direction so that the beam completely enters the effective transmission area of ​​the PBS. Adjust the incident angle of the laser along the Z-axis direction so that the beam completely matches the optical crystal axis direction of the PBS.

[0062] S3: Polarization state optimization: Use a polarization measurement device to monitor the polarization state of the PBS transmitted light in real time. By adjusting the relative angle between the laser module and the PBS, the transmission ratio of S polarized light is gradually reduced to optimize the polarization state.

[0063] S4: Verification and locking: When the polarization extinction ratio of the PBS transmitted light reaches greater than 100:1, the positional relationship between the laser module and the PBS is locked.

[0064] The transmitted light test of the optical path effect can use a polarization extinction ratio meter to test the polarization performance of the PBS transmitted light to ensure that the purity of the P polarized light is greater than 99%. The reflected light test of the optical path effect: Test the PBS reflected light path to ensure that the S polarized light is completely separated and does not enter the main optical path.

[0065] The miniaturized multifunctional laser module of this application integrates multiple functions such as polarization control, power stabilization, spectrum switching, high-speed switching and power attenuation, simplifying the complex design of traditional laser systems. Through a compact modular structure design, the system volume and power consumption are reduced, which is suitable for portable devices and industrial application scenarios. By providing functions such as a polarization extinction ratio greater than 100:1, sub-microsecond fast response, and high-precision power regulation, it is adapted to a variety of precision application scenarios. The laser module supports laser output with different spectral half-widths (5nm and 10nm) to meet the flexible requirements of spectral width in specific scenarios. With the combination of collimating lenses and polarization-maintaining fibers, high-efficiency fiber-coupled output is achieved to ensure optical path stability and output quality.

[0066] Example 1

[0067] In precision optical measurement systems, lasers are required to have high spectral stability, controllable power output, and excellent polarization characteristics for use in micro-displacement detection, interferometry, and other scenarios. To meet these requirements, the following steps are used to prepare a miniaturized multifunctional laser module that meets the requirements of precision optical measurement. The preparation steps include:

[0068] S1: Select lasers with different spectral full width at half maximum.

[0069] According to the application requirements, a laser light source with a central wavelength of 852nm is selected from the standard superluminescent diode (SLD) or semiconductor laser (LD) series. For example, two specifications of SLD with 5nm and 10nm spectral half-maximum full width (FWHM) are selected to meet various spectral width switching requirements. The light source (laser) is fixed on a dedicated laser mount through an adapter base, and a high-precision calibration tool is used to ensure that its optical axis is consistent with the optical path of the optical system.

[0070] S2: Shape the laser beam.

[0071] The divergent beam output by the SLD is optimized using a beam shaping device. The beam shaping device includes a collimating lens, a beam expander, and a converging lens. First, the collimating lens is made of a high-refractive index material (such as BK7 or quartz), and the beam divergence angle is compressed through the collimating lens to make it have a smaller divergence range; then the beam diameter is expanded to the required range through a high-precision mechanical adjustment frame beam expander to improve the beam uniformity; the converging lens adopts an aspheric design, and the optical simulation software is used to optimize the beam path, and the optimized beam shape is adjusted to an approximately circular Gaussian beam. The above optical components are fixed by a high-precision optical bracket to ensure the alignment of the optical path, and a six-dimensional adjustment platform (XYZ position adjustment and angle adjustment) is used for fine-tuning.

[0072] S3: Assemble the laser and the shaping optical path to form a module.

[0073] Specifically, the laser module is based on an integrated design and is encapsulated in an aluminum alloy or stainless steel shell to ensure the compactness and stability of the structure. The laser light source and the shaped optical path are connected by threaded connections and optical fiber clips to ensure efficient optical path transmission. The integrated semiconductor cooler (TEC) is installed at the bottom of the laser using thermal conductive silicone and heat pipe technology. Combined with the temperature control circuit (composed of a thermistor and a PID controller), the internal temperature of the module is monitored and adjusted in real time to maintain a precise temperature control range of ±0.1°C. After all components are assembled, the module optical path is precisely calibrated using an automatic collimator and a laser interferometer to ensure that the optical axis of the shaped beam is aligned with the optical axis of the optical element.

[0074] S4: Embed the laser module assembled in S3 into the optical control module.

[0075] Specifically, the laser module is embedded in the optical control module through a standardized mechanical interface, using multi-point fixation to reduce the impact of vibration, and ensuring optical alignment through docking optical path flanges.

[0076] The optical control module includes a polarization beam splitter (PBS), a beam splitter (BS), a high-speed shutter, and an optical attenuator. The polarization beam splitter is installed inside the module through a flexible optical fixture. Its incident angle is adjusted to strictly align its optical axis with the laser output beam to ensure a polarization extinction ratio of >100:1. The beam splitter is fixed on a precision rotating platform, splits the light at a ratio of 99:1, and detects the feedback beam power in real time through a photodetector (PD). The negative feedback control circuit is connected to dynamically adjust the laser power. A voltage-driven piezoelectric ceramic actuator is used to achieve sub-microsecond switching response, and the high-speed shutter is assembled in the optical path at the rear end of the module. The optical attenuator is installed at the light outlet of the module using a mechanical turntable design to provide multiple fixed-rate power adjustment.

[0077] S5: Couple the received light and output it through the fiber collimation coupler.

[0078] Specifically, a collimating lens is used to compress the divergence angle of the beam in the main optical path to ensure the collimation of the beam. The fiber collimating coupler is installed at the light outlet of the module, and the beam and the optical fiber are aligned by mechanically adjusting the flange and the fine-tuning platform. A single-mode polarization-maintaining fiber is used as the pigtail, which is fixed to the collimating coupler by a precision fiber clamp. The fiber end face cleaning device is used to clean the surface of the pigtail to avoid coupling loss. After the system is assembled, the polarization purity of the collimated light is tested to ensure that the polarization performance meets the design requirements.

[0079] S6: All modules are integrated into an integrated structure and fixed on a high-precision platform.

[0080] High-precision platforms such as aviation-grade aluminum alloy substrates have excellent heat dissipation performance. Shock-absorbing pads and heat insulation plates are used at key interfaces to reduce the impact of environmental vibration and temperature changes on the module. The module shell is made of lightweight aluminum alloy material, and standard interfaces are reserved on the shell for fixing in portable optical instruments and equipment.

[0081] Through the assembly method of this embodiment, the volume of the module after assembly is less than 200mm×150mm×100mm, the total weight is less than 1.5kg, the spectral width can be flexibly switched between 5nm and 10nm, the output power fluctuation is less than ±0.5%, the polarization extinction ratio is greater than 100:1, and sub-microsecond optical path switching can be achieved through a high-speed shutter, which is suitable for a variety of dynamic precision measurement scenarios.

[0082] Example 2

[0083] By comparing the structures of the laser in the prior art and the miniaturized multifunctional laser module of the present invention, the advantages of the miniaturized multifunctional laser module of the present invention are explained.

[0084]

[0085]

[0086] The present invention also records a method for controlling the optical path of a miniaturized multifunctional laser module, the method comprising: step 1: starting the laser light source, the light beam output by the laser light source passes through a collimating lens, a beam expander and a convergent lens in turn, and the divergence angle, diameter and shape of the light beam are optimized to shape the light beam into a Gaussian beam that is approximately circular, and the operating temperature of the laser module is adjusted by a semiconductor refrigerator, and the temperature is controlled within a preset range. The purpose of step 1 is to reduce the divergence angle of the laser beam by beam shaping, improve the collimation of the light beam, and ensure efficient transmission and processing of subsequent optical paths. Adjust the beam diameter and shape, optimize the light beam into a Gaussian beam that is approximately circular through beam expansion and convergence operations, improve the beam quality, and adapt the optical control module to the beam quality requirements. Use a semiconductor refrigerator (TEC) to monitor and adjust the operating temperature of the laser module in real time, reduce spectral drift and power fluctuations caused by temperature changes, and ensure that the light source operates under high stability conditions.

[0087] It should be noted that in precision spectral measurement, communication and interferometry applications, wavelength drift will reduce the measurement accuracy and stability of the system. In addition, the dynamic instability of laser power (such as an increase in the power fluctuation range) will affect the system's power regulation capability and reduce the reliability of precision measurement equipment.

[0088] The semiconductor cooler (TEC) controls the operating temperature of the light source within the range of ±0.1℃.

[0089] In step 1, the divergence angle θ of the light beam is adjusted to the optimal value through the collimating lens and the beam expander. The divergence angle θ of the light beam is expressed by the following formula:

[0090]

[0091] Where: d is the beam diameter and f is the focal length of the lens.

[0092] The beam diameter d is increased by a beam expander, the divergence angle θ is reduced, and the collimation is improved.

[0093] The central wavelength λ of the semiconductor laser is related to the temperature T. The wavelength drift of the semiconductor laser is expressed by the following formula:

[0094] Δλ=k·ΔT(2)

[0095] Where: k is the temperature sensitivity coefficient.

[0096] By controlling the temperature within ±0.1°C through a semiconductor cooler (TEC), the wavelength drift Δλ can be limited to less than 0.01nm, significantly improving the spectrum and power stability.

[0097] Step 2: The shaped light beam is passed to a polarization beam splitter and a beam splitter in the same optical path. The polarization beam splitter is configured to transmit P polarized light and reflect S polarized light by adjusting the alignment direction of the incident angle of the light beam with the optical axis, thereby achieving a polarization extinction ratio ≥ 100:1.

[0098] The purpose of step 2 is to optimize the polarization state of the light beam using a polarization beam splitter (PBS), separate P polarized light and S polarized light through PBS, eliminate unnecessary polarization components, and improve polarization purity. By adjusting the angle at which the light beam is incident on the PBS, the polarization extinction ratio reaches a high performance index greater than 100:1 to meet application scenarios with high polarization requirements. A polarization meter is used to monitor the polarization state of the PBS transmitted light in real time to ensure that the purity of the P polarized light is greater than 99%, providing high-quality polarized light with good consistency for subsequent optical functions.

[0099] Polarization beam splitter (PBS) uses Brewster angle formula to separate the polarization of light beams in the same optical path:

[0100]

[0101] Where: θ B is the Brewster angle; n1 and n2 are the refractive indices of the medium through which the light beam passes.

[0102] By adjusting the incident angle θ of the polarization beam splitter (PBS) B , so that P polarized light is transmitted and S polarized light is reflected, achieving polarization separation.

[0103] Polarization purity is expressed by:

[0104]

[0105] Where: I P and I S are the intensities of P polarized light and S polarized light respectively.

[0106] This application achieves a polarization extinction ratio of ≥100:1 by precisely adjusting the optical axis of the PBS and the incident direction of the light beam, and the P-polarized light purity of the output light beam is maintained at more than 99%. Efficient polarization control is achieved in the same optical path without the need for additional optical components, reducing the complexity of the optical path. The output beam has a high polarization purity, improves the measurement accuracy, and meets the needs of precision optical measurement.

[0107] Step 3: The highly polarized light beam transmitted through the polarization beam splitter prism directly enters the beam splitter, which is configured to split the light beam in a ratio of 99:1 in the same optical path. 99% of the light beam is transmitted to the optical path protection and adjustment module of the downstream main optical path, and 1% of the light beam is used as a feedback beam to enter the optical detector for real-time detection of optical power.

[0108] The purpose of step 3 is to use a beam splitter (BS) to split the beam into a main beam and a feedback beam at a ratio of 99:1, ensuring that the main beam delivers most of the power for the target application, while the feedback beam is used for real-time power monitoring. The power of the feedback beam is detected by the photodetector (PD) in the feedback control module, and the drive current of the laser is dynamically adjusted in combination with the negative feedback circuit to achieve high-precision stability control of the power. The dynamic fluctuation range of the output optical power is guaranteed to be less than ±0.5%, meeting the strict requirements of high-precision measurement or operation on optical power stability.

[0109] The beam splitting of a beam splitter is expressed by the following formula:

[0110] R+T=1 (5)

[0111] Where: R and T are reflectivity and transmittance respectively.

[0112] The power of the feedback beam checked by the optical detector is expressed by the following formula:

[0113] I=I0+k·P t -P f ) (6)

[0114] Where: I is the laser driving current; I0 ​​is the initial current; k is the feedback gain; P t and P f are the target power and the feedback power respectively.

[0115] The dynamic fluctuation of output power is less than ±0.5% through the feedback adjustment of the optical detector. The power is dynamically monitored and adjusted through the feedback beam in the same optical path to ensure power stability. The output power fluctuation range is extremely small, which is suitable for high-precision measurement and application scenarios.

[0116] Step 4: The light beam in the main optical path is transmitted to the Faraday isolator, high-speed shutter and attenuation wheel in the optical path protection and adjustment module in sequence.

[0117] The purpose of step 4 is to use a Faraday isolator to isolate the downstream reflected light, prevent the reflected light from returning to the laser light source, avoid mode hopping, amplitude fluctuation or frequency shift caused by the reflected light, and ensure the stability of the laser operation. The high-speed shutter is used to achieve sub-microsecond optical path fast switching function to meet the application requirements of high dynamic range scenarios, such as fast signal modulation and high-frequency operation. The attenuation wheel is used for multi-speed optical power adjustment. Users can choose different power outputs according to their needs to ensure that the laser is suitable for various precision application scenarios.

[0118] The attenuation factor of the attenuation wheel is expressed by the following formula:

[0119]

[0120] Where: P in and P out are the powers before and after attenuation respectively; A is the attenuation ratio.

[0121] The attenuation wheel provides precise power output through multi-speed adjustment, and the power adjustment accuracy is high.

[0122] The response time of a high-speed shutter is expressed by the following formula:

[0123]

[0124] Where: τ is the response time; L is the switch stroke; v is the drive speed.

[0125] The high-speed shutter response time of this application is less than 1 microsecond, which meets the requirements of high dynamic range scenarios. The high-speed switch response speed is fast and is suitable for fast signal modulation and high-frequency dynamic applications.

[0126] Spectral switching is achieved through formula (2). This application uses a semiconductor cooler (TEC) to control the temperature within the range of ±0.1°C, which minimizes the wavelength drift and ensures the stability of the 5nm and 10nm spectrum half-width switching. The spectrum switching function is realized in the same optical path, and the output is stable, meeting the application scenarios of various spectrum requirements.

[0127] Step 5: The main beam is optimized for divergence angle through the collimating lens in the fiber coupling module, and the beam is efficiently coupled to the single-mode polarization-maintaining fiber using the precision adjustment platform in the fiber collimating coupler. The polarization characteristics of the beam are output through the single-mode polarization-maintaining fiber.

[0128] The purpose of step 5 is to use a collimating lens to compress the divergence angle of the main beam, optimize the beam collimation, and improve the efficiency of fiber coupling. The fiber collimating coupler ensures efficient alignment of the beam with the single-mode polarization-maintaining fiber through a precision fine-tuning platform, achieves high-quality coupling of the beam, and ensures that the coupling efficiency is greater than 90%. The output single-mode polarization-maintaining fiber maintains the polarization characteristics of the beam, meeting the requirements of high-precision application scenarios for beam consistency and polarization characteristics.

[0129] The collimation and coupling efficiency are expressed by the following equation:

[0130]

[0131] Where: η represents the coupling efficiency between the light beam and the optical fiber, ranging from 0 to 1 (or expressed as a percentage of 0% to 100%). The higher the value, the better the mode matching between the light beam and the optical fiber, and the smaller the coupling loss; E beam (x, y) represents the transverse electric field distribution of the laser output beam, which depends on the intensity distribution of the beam in the cross section (x-axis and y-axis); The conjugate complex number that represents the mode field distribution (transverse electric field distribution) of the optical fiber is used to describe the acceptance mode of the optical fiber; * represents the conjugate complex number (complex conjugate). In the description of electromagnetic waves, the complex conjugate represents the symmetry of the electric field component in phase and is used to calculate the mode overlap integral.

[0132] This application optimizes the matching of the beam and the optical fiber through a collimating lens and a precision adjustment platform to ensure a coupling efficiency of ≥90%. The beam in the same optical path maintains high collimation and polarization consistency and is transmitted to a single-mode polarization-maintaining optical fiber, so the output beam has high stability and high polarization consistency, and the measurement accuracy is high.

[0133] Example 3

[0134] In order to verify the technical effect of the optical path control method of the miniaturized multifunctional laser module of the present invention, a discrete laser module commonly used in the prior art is selected as a comparison object, and the optical path performance of the two systems is compared and analyzed. The following takes the precision spectrum measurement scenario as an example to conduct experimental testing and quantitative analysis.

[0135] The experimental system configuration of the existing technology: single laser light source, external polarizer, power regulator, spectrum switching component; power adjustment range: ±1%; polarization extinction ratio: 80:1; high-speed shutter response time: 2 milliseconds; spectrum half-height full width switching: dependent on mechanical filters.

[0136] The experimental system configuration of the present invention is as follows: miniaturized multifunctional laser module, modular integrated design; power adjustment range: ±0.5%; polarization extinction ratio: ≥100:1; high-speed shutter response time: <1 microsecond; spectral half-width switching: achieved through a built-in laser module (5nm and 10nm).

[0137] The test indicators include polarization extinction ratio, power stability, spectrum switching stability, shutter response time, and fiber coupling efficiency.

[0138] Experimental data and comparison table

[0139]

[0140]

[0141] It can be seen from the experimental data and the comparison table that the existing lasers rely on external polarizers or wave plates, and the polarization extinction ratio is affected by the external environment (such as vibration and temperature), and the extinction ratio is only 80:1; the present invention uses a polarization beam splitter (PBS) and an optimized optical path alignment design to increase the extinction ratio to ≥100:1, and the polarization purity of the output beam is greater than 99%, meeting the needs of precision measurement scenarios with high polarization requirements. The existing laser uses an external power adjustment module, the feedback adjustment is slow, and the dynamic fluctuation range is ±1%; the present invention integrates a feedback control module, combined with a negative feedback circuit, to achieve power dynamic fluctuation range control within ±0.5%, meeting the strict requirements of high-precision optical measurement for power stability. The existing laser switches the spectrum half-height full width through a mechanical filter, the switching time is long (>5 seconds), and the stability is poor; the laser module of the present invention supports fast switching of 5nm and 10nm spectrum widths, the switching time is less than 0.1 seconds, and the semiconductor cooler (TEC) is used to control the wavelength drift to <0.01nm. The existing laser mechanical shutter response time is greater than 2 milliseconds, which is difficult to meet the high dynamic range application scenarios; the present invention has a built-in voltage-driven high-speed shutter with a response time of less than 1 microsecond, which meets the needs of fast signal modulation and high-frequency operation. The existing laser beam collimation and coupling matching performance is limited, and the coupling efficiency is about 80%; the present invention optimizes the collimation and coupling matching through a precision adjustment platform, and the fiber coupling efficiency is increased to ≥90%.

[0142] The miniaturized multifunctional laser module of the present invention realizes the generation, polarization adjustment, splitting, protection and efficient fiber coupling of light beams by integrating laser modules, optical control modules, optical path protection and adjustment modules and fiber coupling modules, and has compact structure and stable performance. The power is accurately monitored through a 99:1 splitting ratio, and the safety and stable output of the light path are ensured by combining a Faraday isolator, a high-speed shutter and an attenuation wheel. The single-mode polarization-maintaining fiber achieves high-quality, highly polarized light beam output. The module supports two spectral half-width specifications to meet the needs of different scenarios; the beam shaping device optimizes the beam quality, and the semiconductor refrigerator ensures spectral stability. The feedback control module adjusts the power in real time, and the polarization measurement device monitors and locks the state where the polarization extinction ratio is greater than 100:1 to avoid performance degradation caused by position offset, and ensure high stability and high polarization characteristics of the system.

[0143] The above is only an embodiment of the present invention, and the common sense such as the known specific structure and characteristics in the scheme is not described in detail here. For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive, and the scope of the present invention is defined by the attached claims rather than the above description, so it is intended to include all changes within the meaning and scope of the equivalent elements of the claims. Any figure mark in the claims should not be regarded as limiting the claims involved.

Claims

1. A miniaturized multifunctional laser module, characterized in that: Its structure includes the following in sequence along the same optical axis: A laser module, including a laser and a beam shaping device; An optical control module, comprising a polarization beam splitter prism and a beam splitter; wherein the polarization beam splitter prism is used to adjust the polarization state of the laser beam, and the beam splitter is used to split the beam in a ratio of 99:1; Optical path protection and adjustment module, including Faraday isolator, high-speed shutter and attenuation wheel; Fiber coupling module, including collimating lens, precision adjustment platform and single-mode polarization-maintaining fiber; The laser is used to generate a light beam, which is shaped by a beam shaping device and transmitted to the optical control module; the polarization beam splitter in the optical control module adjusts the light beam into a highly polarized light beam, and transmits the highly polarized light beam to the beam splitter; the beam splitter splits the highly polarized light beam in a ratio of 99:1, wherein 99% of the main light beam is transmitted to the optical path protection and adjustment module, and 1% of the feedback light beam is introduced into the feedback control module for power monitoring; the optical path protection and adjustment module is used to protect and adjust the main light beam, wherein the main light beam passes through the Faraday isolator, the high-speed shutter and the attenuation wheel in sequence, and is transmitted to the optical fiber coupling module; the optical fiber coupling module collimates and adjusts the main light beam through a collimating lens, and finally couples it into the single-mode polarization-maintaining optical fiber through the precision adjustment platform to achieve stable optical fiber output.

2. The miniaturized multifunctional laser module according to claim 1, characterized in that: The laser module is configured to support two spectral full width half maximum specifications.

3. The miniaturized multifunctional laser module according to claim 1, characterized in that: The laser module also includes a semiconductor refrigerator, which is used to adjust the operating temperature of the laser module and control the temperature within a preset range.

4. The miniaturized multifunctional laser module according to claim 1, characterized in that: The beam shaping device includes a collimating lens, a beam expander and a converging lens, which are configured to shape the divergent laser beam to adjust it into a Gaussian beam that is approximately circular; the semiconductor refrigerator is configured to monitor the operating temperature of the laser module in real time, and accurately adjust the temperature through a temperature control circuit to ensure the spectral output stability of the laser light source.

5. The miniaturized multifunctional laser module according to claim 1, characterized in that: The feedback control module includes a light detector and a negative feedback circuit, wherein the light detector is used to detect the power signal of the beam feedback from the spectroscope, and the negative feedback circuit adjusts the output power of the laser module according to the power signal.

6. The miniaturized multifunctional laser module according to claim 1, characterized in that: The Faraday isolator in the optical path protection and adjustment module is used to isolate the back-reflected light to prevent it from returning to the laser light source; the high-speed shutter is used to achieve rapid switching of the optical path; and the attenuation wheel is used to achieve fixed-rate attenuation of multiple gears of optical power.

7. The miniaturized multifunctional laser module according to claim 1, characterized in that: The collimating lens in the fiber coupling module is configured to optimize the collimation of the light beam; and the precision adjustment platform is configured to efficiently couple the light beam to the single-mode polarization-maintaining fiber.

8. The miniaturized multifunctional laser module according to claim 1, characterized in that: The single-mode polarization-maintaining optical fiber is configured to output a light beam having stable polarization characteristics.

9. A light path control method for a miniaturized multifunctional laser module according to any one of claims 1 to 8, characterized in that: Methods include: Step 1: Start the laser light source, the light beam output by the laser light source passes through a collimating lens, a beam expander and a converging lens in sequence, the divergence angle, diameter and shape of the light beam are optimized to shape the light beam into a Gaussian beam that is approximately circular, and the operating temperature of the laser module is adjusted by a semiconductor cooler to control the temperature within a preset range; Step 2: passing the shaped light beam to a polarization beam splitter and a beam splitter in the same optical path, wherein the polarization beam splitter is configured to transmit P polarized light and reflect S polarized light by adjusting the alignment direction of the incident angle of the light beam with the optical axis, thereby achieving a polarization extinction ratio of ≥100:1; Step 3: The highly polarized light beam transmitted through the polarization beam splitter prism directly enters the beam splitter, which is configured to split the light beam in a ratio of 99:1 in the same optical path, 99% of the light beam is transmitted to the optical path protection and adjustment module of the downstream main optical path, and 1% of the light beam is used as a feedback beam to enter the optical detector for real-time detection of optical power; Step 4: The light beam in the main optical path is transmitted to the Faraday isolator, the high-speed shutter and the attenuation wheel in the optical path protection and adjustment module in sequence; Step 5: The main beam is optimized for divergence angle through the collimating lens in the fiber coupling module, and the beam is efficiently coupled to the single-mode polarization-maintaining fiber using the precision adjustment platform in the fiber collimating coupler. The polarization characteristics of the beam are output through the single-mode polarization-maintaining fiber.

10. The optical path control method according to claim 9, characterized in that: The polarization state of the light beam is monitored in real time by a polarization measuring device, and the positional relationship between the laser module and the polarization beam splitter prism is locked when the polarization extinction ratio of the light transmitted by the polarization beam splitter prism reaches greater than 100:1.

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