Miniaturized multifunctional laser module and optical path control method thereof

Abstract

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

Description

Technical Field

[0001] This invention belongs to the field of optoelectronic technology, and more specifically, relates to a miniaturized multifunctional laser module and its optical path control method. Background Technology

[0002] With the rapid development of optoelectronic technology, laser technology has been widely applied in many fields, and the requirements for laser luminescence performance are also increasing. In the current technological context, lasers and their modules are widely used in high-precision applications such as angle measurement, optical surface inspection, control, chip inspection, ion counting, spectral analysis, and DNA molecular sequencing. These applications place higher demands on lasers, and laser technology is continuously developing towards higher quality, higher stability, single polarization, low power consumption, low noise, and smaller size.

[0003] However, existing laser technology still has several shortcomings, mainly in the following aspects:

[0004] 1. Polarization Control and Power Stability Issues: Current laser systems typically employ external polarization control modules and independent power stability control modules, implemented through polarizers, waveplates, or polarization control circuits. This discrete design requires additional optical or electronic components, leading to system complexity, increased size, and higher overall power consumption. Furthermore, the assembly accuracy of these external modules affects laser performance; even slight deviations can result in a reduced polarization ratio or power instability, especially in environments with significant vibration or temperature variations.

[0005] 2. Power Regulation and High-Speed ​​Switching Response Speed ​​and Accuracy Issues: Power regulation and high-speed switching functions of lasers are typically achieved through electro-optic modulators or mechanical shutters. The regulation speed of these traditional components is limited by the drive circuitry and mechanical inertia. For example, the response time of common mechanical shutters is several milliseconds, which is insufficient for high dynamic range applications requiring sub-microsecond regulation. Furthermore, due to the nonlinear characteristics of electronic drive circuits and the physical limitations of components, control accuracy is usually not high, leading to power fluctuations or instability during rapid switching.

[0006] 3. Stability and Cost Issues of Spectral Full Width-at-Half (FWHM) Switching: Existing technologies typically achieve FWHM 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 decreased adjustment accuracy can lead to spectral performance degradation. Furthermore, such designs are generally costly, have complex manufacturing processes, and are difficult to scale up.

[0007] The aforementioned technical limitations severely restrict the further application of lasers in high-precision measurement and analysis. For example, in DNA sequencing or spectral analysis scenarios, the response speed, stability, and spectral switching capabilities of existing laser technologies are insufficient to meet the demands of complex operations. Therefore, developing a high-performance, multifunctional integrated laser to overcome these technical problems has become a key direction for current research and industrial applications. Summary of the Invention

[0008] This invention addresses the shortcomings of existing technologies by proposing a miniaturized multifunctional laser module and its optical path control method. Through innovative structural design combined with conventional semiconductor laser packaging technology, this laser module successfully achieves multiple functions, including polarization control, power stabilization, power attenuation, high-speed switching, and full width at half maximum (FWHM) switching. Compared to the limitations of traditional laser modules, such as single functionality and non-adjustable FWHM, this invention provides an integrated, high-performance solution, improving the applicability and reliability of lasers and offering new technical support for the field of precision measurement and analysis.

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

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

[0011] The optical control module includes a polarizing beam splitter and a beam splitter; the polarizing beam splitter is used to adjust the polarization state of the laser beam, and the beam splitter is used to split the beam at a ratio of 99:1.

[0012] The optical path protection and adjustment module includes a Faraday isolator, a high-speed shutter, and an attenuation wheel;

[0013] The fiber optic coupling module includes a collimating lens, a precision adjustment platform, and a single-mode polarization-maintaining fiber;

[0014] The laser generates a beam, which is shaped by a beam shaping device and then transmitted to the optical control module. A polarizing beam splitter in the optical control module adjusts the beam into a highly polarized beam and transmits it to the beam splitter. The beam splitter splits the highly polarized beam at a 99:1 ratio, with 99% of the main beam transmitted to the optical path protection and adjustment module and 1% of the feedback beam fed into the feedback control module for power monitoring. The optical path protection and adjustment module protects and adjusts the main beam, which sequentially passes through the Faraday isolator, high-speed shutter, and attenuation wheel before being transmitted to the fiber coupling module. The fiber coupling module collimates and adjusts the main beam using a collimating lens, and finally couples it into the single-mode polarization-maintaining fiber via the precision adjustment platform to achieve stable fiber output.

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

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

[0017] In a preferred embodiment, the beam shaping device further includes a collimating lens, a beam expander, and a converging lens, configured to shape the diverging laser beam into an approximately circular Gaussian beam; the semiconductor cooler is configured to monitor the operating temperature of the laser module in real time and precisely adjust the temperature through a temperature control circuit to ensure the spectral output stability of the laser source.

[0018] In a preferred implementation, the feedback control module further includes a photodetector and a negative feedback circuit, wherein the photodetector is used to detect the power signal of the beam fed back by the beam splitter, and the negative feedback circuit adjusts the output power of the laser module according to the power signal.

[0019] In a preferred implementation, the Faraday isolator in the optical path protection and adjustment module is used to isolate back-reflected light to prevent it from returning to the laser 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 optical power levels.

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

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

[0022] On the other hand, the present invention also provides an optical path control method based on any one of the miniaturized multifunctional laser modules described above, the method comprising:

[0023] Step 1: Start the laser source. The laser beam output by the laser source passes through a collimating lens, a beam expander and a converging lens in sequence to optimize the divergence angle, diameter and shape of the beam, so as to shape the beam into an approximately circular Gaussian beam. The operating temperature of the laser module is adjusted by a semiconductor cooler and the temperature is controlled within a preset range.

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

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

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

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

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

[0029] The beneficial effects of this invention are:

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

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

[0032] Third, in the preferred implementation, the beam shaping device of the present invention shapes the diverging laser beam into an approximately circular Gaussian beam by combining a collimating lens, a beam expander, and a converging lens, thereby improving the beam quality and adaptability; the semiconductor cooler ensures the stability of the light source's spectral output by real-time monitoring and precise adjustment of the laser module's operating temperature.

[0033] Fourth, in the preferred implementation, the laser module of the present invention achieves precise monitoring and real-time adjustment of laser power through a feedback control module, ensuring stable output power; the Faraday isolator, high-speed shutter, and attenuation wheel in the optical path protection and adjustment module provide reflection isolation, fast switching, and precise power control functions, respectively, effectively improving the system's safety and adaptability; the fiber coupling module achieves efficient and stable fiber coupling through an optimized collimating lens and a 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 this invention precisely optimizes the divergence angle, diameter, and shape of the beam to shape it into an approximately circular Gaussian beam. Simultaneously, it utilizes a polarizing beam splitter and a beam splitter to achieve high polarization characteristics and precise beam splitting, ensuring a polarization extinction ratio ≥100:1 and efficient energy distribution of the beam. Real-time detection and feedback adjustment of the optical power improve the system's stability and reliability. Combined with multiple control methods of the optical path protection module, optical path interference and power fluctuations are effectively avoided. Finally, precise adjustment achieves efficient beam coupling and polarization characteristic optimization, ensuring high quality and stability of the output beam.

[0035] Sixth, in the preferred implementation, the present invention monitors the polarization state of the beam in real time through a polarization measurement device, and locks the positional relationship between the laser module and the polarization beam splitter when the polarization extinction ratio of the transmitted light of the polarization beam splitter reaches greater than 100:1, which effectively ensures the stability of the high polarization extinction ratio of the system, improves the accuracy and consistency of the beam polarization characteristics, and avoids the degradation of polarization performance caused by positional offset. Attached Figure Description

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

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

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

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

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

[0041] Figure 6 This is a flowchart of an optical path control method for a miniaturized multifunctional laser module according to an embodiment of the present invention. Detailed Implementation

[0042] To enable those skilled in the art to better understand the technical solutions of this application, the following will provide a more detailed description of this application in conjunction with 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 should not be construed as indicating or implying relative importance; the term "multiple" refers to two or more unless otherwise expressly defined. The terms "install," "connect," "link," and "fix" should be interpreted broadly. For example, "connect" can mean a fixed connection, a detachable connection, or an integral connection; "link" can mean a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0044] In the description of this application, it should be understood that the terms "upper", "lower", "left", "right", "front", "rear", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or unit referred to must have a specific orientation or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0045] In the description of this specification, the terms "one embodiment / mode," "some embodiments / modes," "specific embodiment / mode," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment / mode or example, which is included in at least one embodiment / mode or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment / mode or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments / modes or examples.

[0046] As per the instruction manual Figure 1This invention describes a miniaturized multifunctional laser module, whose structure includes, sequentially along the same optical axis, a laser module, an optical control module, an optical path protection and adjustment module, and an optical fiber coupling module. Through efficient integration of these modules and optimized optical path transmission, it achieves multifunctional designs such as polarization control, power stabilization, power attenuation, high-speed switching, and full-width-half-maximum (FWHM) spectral switching, meeting the needs of various precision applications.

[0047] The laser module includes a laser source (such as a superluminescent diode (SLD) or a semiconductor laser (LD), a beam shaping device, and a thermoelectric cooler (TEC). The laser source generates a laser beam with a center wavelength of 852 nm, with a full width at half maximum (FWHM) of 5 nm and 10 nm. Different spectral widths can be selected for specific applications, enabling spectral switching. The beam shaping device shapes the diverging laser beam through compression, expansion, or convergence operations, adjusting the beam into a nearly circular Gaussian beam, improving beam uniformity and quality. The TEC works in conjunction with a thermistor and temperature control circuit to monitor the laser module's operating temperature in real time, ensuring the source operates within its optimal temperature range, reducing thermal drift, and enhancing the stability of laser power and spectral output.

[0048] As per the instruction manual Figure 2 In the laser module, the laser output beam is shaped by a beam shaping device and then transmitted to the optical control module, providing a high-quality input light source for subsequent functions. Through modular design, the spectral switching and beam shaping functions are integrated into the laser module, while the temperature control function of the thermoelectric 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 only one laser module, the system uses only one laser module as the light source, resulting in a simple optical path design, compact structure, and ease of 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. Because only one laser module is used, the system size and power consumption are significantly reduced, making it suitable for handheld devices or small optical systems. It can be used for laboratory calibration or as a reference light source, providing stable laser output for other devices.

[0050] When multiple laser modules are used, the system contains multiple laser modules capable of simultaneously or switching between outputting multiple beams. The laser modules can operate independently or combine beams using optical elements (such as beam splitters or fiber couplers). This allows for simultaneous output or rapid switching of multiple wavelength light sources, suitable for applications requiring multi-wavelength lasers, such as fluorescence spectroscopy and bioimaging. Beams from multiple laser modules can be combined to increase output power for laser processing, welding, or material surface treatment. Beams of different wavelengths can be used for multi-mode interferometry experiments, enhancing the system's measurement capabilities. Furthermore, in industrial and medical applications, the redundancy of multiple laser modules improves system reliability.

[0051] The optical control module includes a polarizing beam splitter (PBS) and a beam splitter (BS). The PBS adjusts the polarization state of the laser beam, eliminating unnecessary polarization components and achieving a high-performance beam polarization extinction ratio greater than 100:1. The PBS improves beam consistency and stability, making it particularly suitable for precision measurement scenarios with high polarization requirements. The BS splits the beam at a 99:1 power ratio, with 99% of the main beam entering the main optical path for further propagation, and the remaining 1% being fed back to the feedback control module for real-time power monitoring. The precise beam splitting function of the BS provides a reliable guarantee for the coordinated operation of the main optical path and feedback control.

[0052] As per the instruction manual Figure 3 The highly polarized beam output from the polarizing beam splitter (PBS) enters the beam splitter (BS). The beam splitter divides the beam into two parts: the main beam (99% power) is transmitted to the optical path protection and adjustment module, and the feedback beam (1% power) enters the feedback control module, where the optical power is detected. By tightly integrating polarization control and power splitting functions through the optical control module, the number of optical path components is reduced, while efficient beam splitting and real-time feedback control are achieved, simplifying the structural design.

[0053] In the implementation of this application, the feedback control module uses a photodetector (PD). The photodetector (PD) is used to detect the power of the beam after splitting and adjusts the output power of the laser through a negative feedback circuit to ensure the stability of the optical power.

[0054] The optical path protection and adjustment module includes a Faraday isolator, a high-speed shutter, and an attenuation wheel. The Faraday isolator prevents back-reflected light from the downstream optical path from returning to the laser source, avoiding mode hopping, amplitude fluctuations, or frequency shifts caused by reflected light, thus ensuring the stability and safety of the laser. The high-speed shutter uses a voltage-driven mechanical switch to achieve sub-microsecond-level rapid optical path switching, meeting the stringent response speed requirements of high dynamic range applications. Its response speed reaches the sub-microsecond level, satisfying the switching needs of high dynamic range applications. The attenuation wheel provides multiple fixed-rate optical power attenuation functions, allowing users to select the appropriate power output according to their needs, ensuring the laser's adaptability in different scenarios.

[0055] As per the instruction manual Figure 4 In the optical path protection and adjustment module, the main optical beam from the beam splitter passes sequentially through a Faraday isolator (to isolate back-reflected light), a high-speed shutter (to enable rapid switching), and an attenuation wheel (to adjust optical power) before being 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 a modular design, improving both the safety of optical path operation and the flexibility of laser power adjustment.

[0056] The fiber optic 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 beam, optimize the collimation of the beam, and ensure that the beam can be efficiently coupled into the fiber. The single-mode polarization-maintaining fiber is used to maintain the polarization characteristics of the output beam from the fiber, ensuring the stability and consistency of the polarized beam, and improving the coupling efficiency and optical path transmission quality of the fiber.

[0057] As per 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 laser module output beam is unpolarized light with a certain spatial divergence angle and non-uniform polarization. After passing through the beam shaping device, the beam is adjusted into an approximately circular Gaussian beam, but its polarization state still needs optimization. A polarizing beam splitter (PBS) is an optical element capable of separating polarized beams. The PBS relies on the incident angle between the beam and the optical crystal, as well as the beam's polarization direction, to separate P-polarized and S-polarized light: P-polarized light is parallel to the beam's incident plane and can pass through the PBS; S-polarized light is perpendicular to the beam's incident plane and can be reflected by the PBS. Existing laser polarization control typically relies on external polarizers or waveplates, which, limited by component precision and beam characteristics, cannot achieve a high polarization extinction ratio. To address this issue, this 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 PBS.

[0059] The core principle of this application's adjustment of the relative position of the laser module and the polarization beam splitter (PBS) is that, after adjustment, the output beam direction and polarization state of the laser module must be strictly aligned with the optical axis of the PBS. By precisely controlling the relative position and angle between the laser module and the PBS, the incident direction of the 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 in the optical path to ensure that the laser output beam can completely enter the effective working area of ​​the PBS.

[0061] S2: Position Fine-tuning: The spatial position of the laser module is fine-tuned using 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 to ensure the beam center is aligned with the optical axis of the PBS. Adjust the laser height along the Y-axis to ensure the beam fully enters the effective transmission region of the PBS. Adjust the laser's incident angle along the Z-axis to perfectly match the beam with the optical crystal axis of the PBS.

[0062] S3: Polarization State Optimization: The polarization state of the transmitted light from the PBS is monitored in real time using a polarization measurement device. By adjusting the relative angle between the laser module and the PBS, the transmission ratio of S-polarized light is gradually reduced, thus optimizing the polarization state.

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

[0064] The transmitted light effect of the optical path can be tested using a polarization extinction ratio meter to measure the polarization performance of the transmitted light from the PBS, ensuring that the purity of the P-polarized light is greater than 99%. The reflected light effect of the optical path is tested by testing the reflected light path of the PBS to ensure that the S-polarized light is completely separated and does not enter the main optical path.

[0065] This application presents a miniaturized multifunctional laser module that integrates polarization control, power stabilization, spectral switching, high-speed switching, and power attenuation, simplifying the complex design of traditional laser systems. Its compact modular structure reduces system size and power consumption, making it suitable for portable devices and industrial applications. By providing a polarization extinction ratio greater than 100:1, sub-microsecond fast response, and high-precision power adjustment, it adapts to various precision applications. The laser module supports laser output at different spectral full width at half maximum (FWHM) (5nm and 10nm), meeting the flexible spectral width requirements of specific scenarios. The combination of a collimating lens and polarization-maintaining fiber achieves high-efficiency fiber-coupled output, ensuring optical path stability and output quality.

[0066] Example 1

[0067] In precision optical measurement systems, lasers are required to possess high spectral stability, controllable power output, and excellent polarization characteristics for applications such as micro-displacement detection and interferometry. To meet these requirements, a miniaturized multifunctional laser module that satisfies the requirements of precision optical measurement is fabricated using the following steps. The fabrication steps include:

[0068] S1: Select lasers with different full width at half maximum (FWHM) of their spectrum.

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

[0070] S2: Shape the laser beam.

[0071] The diverging beam output from the SLD is optimized using a beam shaping device. This 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). The collimating lens compresses the beam divergence angle, resulting in a smaller divergence range. Then, a high-precision mechanical adjustment frame expands the beam diameter to the required range, improving beam uniformity. The converging lens employs an aspherical design, and optical simulation software optimizes the beam path, adjusting the optimized beam shape to an approximately circular Gaussian beam. All these optical components are fixed by a high-precision optical support to ensure optical path alignment, 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, encapsulated in an aluminum alloy or stainless steel housing to ensure structural compactness and stability. The laser source and the shaping optical path are connected via threaded connections and fiber optic clips, ensuring efficient optical path transmission. An integrated thermoelectric cooler (TEC) is mounted at the bottom of the laser using thermally conductive silicone and heat pipe technology. Combined with a temperature control circuit (composed of a thermistor and a PID controller), it monitors and adjusts the internal temperature of the module in real time, maintaining it within a precise temperature control range of ±0.1℃. After all components are assembled, an automatic collimator and laser interferometer are used to precisely calibrate the module's optical path, ensuring that the shaped beam's optical axis is aligned with the optical axis of the optical components.

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

[0075] Specifically, the laser module is embedded into the optical control module through a standardized mechanical interface, using multi-point fixation to reduce the impact of vibration, while optical alignment is ensured through a docking optical path flange.

[0076] The optical control module includes a polarizing beam splitter (PBS), a beam splitter (BS), a high-speed shutter, and an optical attenuator. The polarizing beam splitter is mounted inside the module using a flexible optical clamp. Its incident angle is adjusted to ensure its optical axis is precisely aligned with the laser output beam, guaranteeing a polarization extinction ratio >100:1. The beam splitter is fixed on a precision rotating platform, splitting the beam at a 99:1 ratio. A photodetector (PD) monitors and provides real-time feedback of the beam power, which is then connected to a negative feedback control circuit to dynamically adjust the laser power. A voltage-driven piezoelectric ceramic actuator achieves sub-microsecond switching response, and the high-speed shutter is integrated into the optical path at the rear of the module. A mechanical rotary design houses the optical attenuator at the module's output port, providing multiple fixed-magnification power adjustments.

[0077] S5: Optical output is coupled and received via an optical fiber collimator.

[0078] Specifically, a collimating lens is used to compress the beam divergence angle of the main optical path, ensuring beam collimation. An optical fiber collimating coupler is installed at the module's output port, and the beam is aligned with the fiber using a mechanical adjustment flange and a fine-tuning platform. A single-mode polarization-maintaining fiber is used as the pigtail, fixed to the collimating coupler with a precision fiber clamp. The pigtail surface is cleaned using a fiber end-face cleaning device to avoid coupling loss. After system assembly, the polarization purity of the collimated light is tested to ensure that the polarization performance meets design requirements.

[0079] S6: Integrates all modules into a single structure and fixes it on a high-precision platform.

[0080] The high-precision platform uses an aerospace-grade aluminum alloy substrate, which has excellent heat dissipation performance. Shock-absorbing pads and heat insulation plates are used at critical interfaces to reduce the impact of environmental vibration and temperature changes on the module. The module housing is made of lightweight aluminum alloy and has pre-installed standard interfaces for mounting in portable optical instruments and equipment.

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

[0082] Example 2

[0083] By comparing the structure of existing lasers with that of 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] This invention also describes an optical path control method for a miniaturized multifunctional laser module. The method includes: Step 1: Starting the laser source, the laser beam output from the laser source sequentially passes through a collimating lens, a beam expander, and a converging lens to optimize the beam's divergence angle, diameter, and shape, shaping the beam into an approximately circular Gaussian beam. The operating temperature of the laser module is adjusted using a thermoelectric cooler (TEC) and controlled within a preset range. The purpose of Step 1 is to reduce the divergence angle of the laser beam by beam shaping, improve beam collimation, and ensure efficient transmission and processing of subsequent optical paths. Adjusting the beam diameter and shape, and optimizing the beam into an approximately circular Gaussian beam through beam expansion and converging operations, improves beam quality and meets the beam quality requirements of the optical control module. The operating temperature of the laser module is monitored and adjusted in real time using a thermoelectric cooler (TEC) to reduce spectral drift and power fluctuations caused by temperature changes, ensuring 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 increased power fluctuation range) will affect the power control capability of the system and reduce the reliability of precision measurement equipment.

[0088] The thermoelectric cooler (TEC) controls the operating temperature of the light source within ±0.1°C.

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

[0090]

[0091] In the formula: d is the beam diameter, and f is the lens focal length.

[0092] Increasing the beam diameter d by using a beam expander reduces the divergence angle θ and improves collimation.

[0093] The center wavelength λ of a semiconductor laser is related to the temperature T, and the wavelength drift of a semiconductor laser is expressed by the following formula:

[0094] Δλ=k·ΔT(2)

[0095] In the formula: k is the temperature sensitivity coefficient.

[0096] By controlling the temperature within ±0.1℃ using a semiconductor cooler (TEC), the wavelength drift Δλ can be limited to below 0.01nm, significantly improving spectral and power stability.

[0097] Step 2: The shaped beam is transmitted to the polarizing beam splitter and beam splitter in the same optical path. The polarizing beam splitter is configured to transmit P-polarized light and reflect S-polarized light by adjusting the incident angle of the beam and the alignment direction of 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 beam using a polarizing beam splitter (PBS). The PBS separates P-polarized and S-polarized light, eliminating unnecessary polarization components and improving polarization purity. By adjusting the angle of the beam incident on the PBS, a high-performance polarization extinction ratio greater than 100:1 is achieved to meet the high polarization requirements of applications. A polarization meter is used to monitor the polarization state of the light transmitted through the PBS in real time, ensuring that the purity of the P-polarized light is greater than 99%, providing consistently high-quality polarized light for subsequent optical functions.

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

[0100]

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

[0102] By adjusting the incident angle θ of the polarizing beam splitter (PBS) B This allows P-polarized light to be transmitted and S-polarized light to be reflected, thus achieving polarization separation.

[0103] Polarization purity is expressed by the following formula:

[0104]

[0105] In the formula: I P and I S These represent the intensities of P-polarized light and S-polarized light, respectively.

[0106] This application achieves a polarization extinction ratio of ≥100:1 and maintains the P-polarized light purity of the output beam above 99% by precisely adjusting the optical axis and incident direction of the PBS. It realizes efficient polarization control within the same optical path, eliminating the need for additional optical components and reducing optical path complexity. The output beam has high polarization purity, improving measurement accuracy and meeting the requirements of precision optical measurements.

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

[0108] The purpose of step 3 is to use a beam splitter (BS) to split the laser beam into a main beam and a feedback beam at a ratio of 99:1. This ensures 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 a photodetector (PD) in the feedback control module, and the laser's drive current is dynamically adjusted using a negative feedback circuit to achieve high-precision and stable power control. This ensures that the dynamic fluctuation range of the output optical power is less than ±0.5%, meeting the stringent requirements for optical power stability in high-precision measurements or operations.

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

[0110] R+T=1 (5)

[0111] In the formula: R and T are reflectivity and transmittance, respectively.

[0112] The power of the feedback beam detected by the photodetector is expressed by the following formula:

[0113] I = I0 + k·P t -P f (6)

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

[0115] Output power dynamic fluctuations are kept below ±0.5% through photodetector feedback adjustment. Power stability is ensured by dynamically monitoring and adjusting the power via a feedback beam within the same optical path. The extremely small output power fluctuation range makes it suitable for high-precision measurement and application scenarios.

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

[0117] The purpose of step 4 is to isolate downstream reflected light using a Faraday isolator, preventing reflected light from returning to the laser source and avoiding mode hopping, amplitude fluctuations, or frequency shifts caused by reflected light, thus ensuring the stability of laser operation. A high-speed shutter enables sub-microsecond-level rapid optical path switching, meeting the application requirements of high dynamic range scenarios, such as fast signal modulation and high-frequency operation. An attenuation wheel allows for multi-level optical power adjustment, enabling users to select different power outputs according to their needs, ensuring the laser is adaptable to various precision application scenarios.

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

[0119]

[0120] In the formula: P in and P out These represent the power before and after attenuation, respectively; A is the attenuation ratio.

[0121] The attenuation wheel provides precise power output through multiple adjustment levels, with high power adjustment accuracy.

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

[0123]

[0124] In the formula: τ is the response time; L is the switching stroke; v is the driving 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 switching response is fast and it is suitable for fast signal modulation and high-frequency dynamic applications.

[0126] Spectral switching is achieved through formula (2). This application uses a thermoelectric cooler (TEC) to control the temperature within ±0.1℃, minimizing wavelength drift and ensuring the stability of the full width at half maximum (FWHM) switching between 5nm and 10nm spectra. The spectral switching function is implemented within the same optical path, providing stable output and meeting the needs of various application scenarios requiring diverse spectral capabilities.

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

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

[0129] Collimation and coupling efficiency are expressed by the following formula:

[0130]

[0131] In the formula: η represents the coupling efficiency between the beam and the fiber, ranging from 0 to 1 (or expressed as a percentage from 0% to 100%). A higher value indicates better mode matching between the beam and the fiber, and lower 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 on the cross-section (x-axis and y-axis); The complex conjugate of the mode field distribution (transverse electric field distribution) of the optical fiber is used to describe the receiving modes of the optical fiber; * denotes the complex conjugate, which in the description of electromagnetic waves represents the phase symmetry of the electric field components and is used to calculate the mode overlap integral.

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

[0133] Example 3

[0134] To verify the technical effectiveness of the optical path control method for the miniaturized multifunctional laser module of this invention, a commonly used discrete laser module in the prior art was selected as a comparison object, and the optical path performance of the two systems was compared and analyzed. The following uses a precision spectral measurement scenario as an example for experimental testing and quantitative analysis.

[0135] The existing experimental system configuration includes: a single laser light source, an external polarizer, a power regulator, and a spectral switching component; power adjustment range: ±1%; polarization extinction ratio: 80:1; high-speed shutter response time: 2 milliseconds; spectral half-width switching: dependent on a mechanical filter.

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

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

[0138] Experimental Data and Comparison Table

[0139]

[0140]

[0141] As can be seen from the experimental data and comparison table, existing lasers rely on external polarizers or waveplates, and their polarization extinction ratio is affected by external environmental factors (such as vibration and temperature), reaching only 80:1. This invention, through a polarizing beam splitter (PBS) and optimized optical path alignment design, improves the extinction ratio to ≥100:1, achieving an output beam polarization purity greater than 99%, meeting the requirements of precision measurement scenarios with high polarization requirements. Existing lasers use external power adjustment modules, resulting in slow feedback adjustment and dynamic fluctuations of ±1%. This invention integrates a feedback control module, combined with a negative feedback circuit, to control the dynamic power fluctuation range within ±0.5%, meeting the stringent power stability requirements of high-precision optical measurements. Existing lasers switch the full width at half maximum (FWHM) of the spectrum using mechanical filters, resulting in long switching times (>5 seconds) and poor stability. The laser module of this invention supports rapid switching between 5nm and 10nm spectral widths, with a switching time of less than 0.1 seconds, while utilizing a semiconductor cooler (TEC) to control wavelength drift to <0.01nm. Existing laser mechanical shutters have response times greater than 2 milliseconds, which is insufficient for high dynamic range applications. This invention incorporates a voltage-driven high-speed shutter with a response time of less than 1 microsecond, meeting the requirements for rapid signal modulation and high-frequency operation. Existing lasers have limited beam collimation and coupling matching performance, with a coupling efficiency of approximately 80%. This invention optimizes collimation and coupling matching through a precision adjustment platform, increasing fiber coupling efficiency to ≥90%.

[0142] This invention presents a miniaturized multifunctional laser module that integrates a laser module, an optical control module, an optical path protection and adjustment module, and an optical fiber coupling module. This achieves beam generation, polarization adjustment, beam splitting, protection, and efficient optical fiber coupling, resulting in a compact structure and stable performance. A 99:1 splitting ratio ensures precise power monitoring, and combined with a Faraday isolator, high-speed shutter, and attenuation wheel, it guarantees safe and stable optical path output. Single-mode polarization-maintaining fiber enables high-quality, highly polarized beam output. The module supports two spectral full width at half maximum (FWHM) specifications to meet the needs of different scenarios. A beam shaping device optimizes beam quality, and a semiconductor cooler ensures spectral stability. A feedback control module adjusts the power in real time, and a polarization measurement device monitors and locks the state where the polarization extinction ratio is greater than 100:1, avoiding performance degradation caused by positional shifts and ensuring high system stability and high polarization characteristics.

[0143] The above descriptions are merely embodiments of the present invention, and common knowledge regarding specific structures and characteristics of the solutions is not described in detail here. It will be apparent to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the present invention is defined by the appended claims rather than the foregoing description. Therefore, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A miniaturized multifunctional laser module, characterized in that, Its structure, along the same optical axis, includes the following components in sequence: A laser module includes a laser and a beam shaping device; the beam shaping device includes a collimating lens, a beam expander, and a converging lens, configured to shape the diverging laser beam into an approximately circular Gaussian beam. The optical control module includes a polarizing beam splitter and a beam splitter; wherein the polarizing beam splitter is used to adjust the polarization state of the laser beam to obtain a highly polarized beam, and the polarization extinction ratio of the highly polarized beam reaches ≥100:1, and the beam splitter is used to split the highly polarized beam at a ratio of 99:

1. The optical path protection and adjustment module includes a Faraday isolator, a high-speed shutter, and an attenuation wheel. The Faraday isolator in the optical path protection and adjustment module is used to isolate back-reflected light to prevent it from returning to the laser source. The high-speed shutter is used to achieve rapid switching of the optical path. The attenuation wheel is used to achieve fixed-rate attenuation of multiple optical power levels. The fiber optic coupling module includes a collimating lens, a precision adjustment platform, and a single-mode polarization-maintaining fiber; The laser generates a beam, which is shaped by a beam shaping device and then transmitted to the optical control module. A polarizing beam splitter in the optical control module adjusts the beam into a highly polarized beam and transmits it to the beam splitter. The beam splitter splits the highly polarized beam at a 99:1 ratio, with 99% of the main beam transmitted to the optical path protection and adjustment module, and 1% of the feedback beam fed into the feedback control module for power monitoring. The optical path protection and adjustment module protects and adjusts the main beam, which sequentially passes through the Faraday isolator, high-speed shutter, and attenuation wheel before being transmitted to the fiber coupling module. The fiber coupling module collimates and adjusts the main beam using a collimating lens, and finally couples it into the single-mode polarization-maintaining fiber through the precision adjustment platform to achieve stable fiber output. The feedback control module includes a photodetector and a negative feedback circuit. The photodetector is used to detect the power signal of the beam fed back by the beam splitter, and the negative feedback circuit adjusts the output power of the laser module according to the power signal. The laser module is configured to support two spectral full width at half maximum (FWHM) specifications.

2. The miniaturized multifunctional laser module according to claim 1, characterized in that, The laser module also includes a semiconductor cooler, which is configured to monitor the operating temperature of the laser module in real time and precisely adjust the temperature through a temperature control circuit to ensure the stability of the spectral output of the laser source.

3. 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 beam; the precision adjustment platform is configured to efficiently couple the beam to a single-mode polarization-maintaining fiber.

4. The miniaturized multifunctional laser module according to claim 1, characterized in that, The single-mode polarization-maintaining fiber is configured to output a beam with stable polarization characteristics.

5. A method for optical path control based on a miniaturized multifunctional laser module according to any one of claims 1-4, characterized in that, The methods include: Step 1: Start the laser source. The laser beam output by the laser source passes through a collimating lens, a beam expander and a converging lens in sequence to optimize the divergence angle, diameter and shape of the beam, so as to shape the beam into an approximately circular Gaussian beam. The operating temperature of the laser module is adjusted by a semiconductor cooler and the temperature is controlled within a preset range. Step 2: The shaped beam is transmitted to a polarizing beam splitter and a beam splitter in the same optical path. The polarizing beam splitter is configured to transmit P-polarized light and reflect S-polarized light by adjusting the incident angle of the beam and the alignment direction of the optical axis, thereby achieving a polarization extinction ratio ≥100:

1. Step 3: The highly polarized beam transmitted through the polarizing beam splitter directly enters the beam splitter. The beam splitter is configured to split the beam in the same optical path at a ratio of 99:

1. 99% of the beam is transmitted to the downstream main optical path optical path protection and adjustment module, and 1% of the beam is used as a feedback beam to enter the photodetector for real-time detection of optical power. Step 4: The beam in the main optical path is sequentially transmitted to the Faraday isolator, high-speed shutter, and attenuation wheel in the optical path protection and adjustment module; Step 5: The main beam is optimized for divergence angle by the collimating lens in the fiber coupling module. The beam is then efficiently coupled to a single-mode polarization-maintaining fiber using the precision adjustment platform in the fiber collimating coupler. The polarization characteristics of the beam are then output through the single-mode polarization-maintaining fiber.

6. The optical path control method according to claim 5, characterized in that, The beam polarization state is monitored in real time by a polarization measurement device, and the positional relationship between the laser module and the polarization beam splitter is locked when the polarization extinction ratio of the transmitted light from the polarization beam splitter reaches greater than 100:1.

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