The cycle time of each processing step for the Polarization-Maintaining Fiber Collimator

Processing Flow and Cycle Description of Polarization-Maintaining Fiber Collimator (PMFC)

The Polarization-Maintaining Fiber Collimator (PMFC) is a high-end optical component that ensures the stable transmission of linearly polarized light. It is mainly used in fields such as optical fiber communication, optical fiber sensors, and optical fiber gyroscopes. Its manufacturing process integrates core technologies such as polarization-maintaining fiber processing, precision optical processing, and polarization alignment, and strictly adheres to quality control standards throughout. The following details the standard cycle of each processing step (based on batch production; the cycle for single set customization can be adjusted according to specifications), clearly presenting the complete cycle from raw materials to finished products for customer reference and planning.

I. Core Raw Material Selection and Pre-treatment Cycle (2-3 days) 

The performance of raw materials directly determines the polarization stability of the polarization-maintaining collimator. The selection and pretreatment strictly follow the high-end industrial standards, and the cycle is stable and controllable. 

1.Raw material screening (1 day): 

Focus on carefully selecting core materials such as polarization-maintaining fibers (preferably panda type or bowtie type), optical lenses (quartz glass or sapphire), mechanical structural components (low thermal expansion coefficient ceramics, Kovar alloy), and optical adhesives (353ND adhesive, UV305 adhesive). Polarization-maintaining fibers need to be tested for birefringence performance and extinction ratio, lenses need to be free of bubbles and impurities, and structural components need to be tested for mechanical strength. The entire process is completed through professional testing equipment to screen out unqualified raw materials, laying a foundation for subsequent processing. 

2. Raw material pretreatment (1-2 days): 

For the qualified polarization-maintaining fibers selected, the outer sheath and coating layer are stripped off, and the end faces are cleaned with lint-free cotton swabs dipped in anhydrous ethanol. The optical lenses are cleaned of surface stains and oxide layers, and the mechanical structural components are initially ground to remove burrs. All raw materials undergo constant-temperature drying treatment (with the environmental temperature controlled at 20 ± 1℃) to prevent deformation or performance deviation during subsequent processing. After the pretreatment is completed, a secondary inspection is conducted to ensure compliance with processing standards. 

II. Precision processing cycle of polarization-maintaining fiber (2-3 days) 

1.The processing accuracy of polarization-maintaining fibers directly affects the quality of polarization state transmission. The process is simple but has extremely high precision requirements, with a controllable cycle. Refer to the relevant process specifications for the preparation of polarization-maintaining fibers for execution. 

Fiber end face processing (1 day): Utilizing precise grinding and polishing techniques, the end faces of polarization-maintaining fibers are treated to a mirror finish. The grinding is carried out according to the interface type (PC/UPC/APC), with the APC interface ground to an 8° bevel. The angle tolerance is controlled within 101.79° ± 0.025°, ensuring the flatness and perpendicularity of the fiber end faces. The surface roughness Ra is ≤ 0.5nm, preventing polarization state distortion caused by end face reflection. 

2. Polarization state calibration and cutting (1-2 days): 

Utilize a dedicated polarization-maintaining fiber alignment system to adjust the polarization direction of the fiber, ensuring a stable polarization state. Precisely cut the fiber, leaving a reasonable length of the core (typically 10mm). After cutting, clean the end face again, and measure the fiber mode field diameter and polarization-dependent loss to ensure compliance with processing requirements and avoid affecting the subsequent coupling effect. 

III. Optical Lens Processing Cycle (6-8 days) 

1.Optical lenses, as the core collimating components, have their processing accuracy determine the collimating effect. Ultra-precision processing technology is adopted, and the entire process is carried out in a constant temperature, constant humidity, and clean workshop. 

Lens rough grinding and fine grinding (3-4 days): 

High-precision cutting equipment is used to cut the optical substrate into the preset size with an error controlled within ±0.001mm. Then, the excess material is removed through rough grinding to initially form the lens contour. Subsequently, fine grinding is carried out using CNC polishing technology, combined with in-situ detection technology. Surface shape data is sampled at intervals of 50μm for real-time adjustment of processing parameters to correct surface shape errors, ensuring that the lens radius of curvature tolerance is ≤±0.001mm. 

2. Precision polishing and anti-reflection coating (3-4 days): 

Fine polishing is carried out using magnetic fluid finishing (MRF) technology to further optimize the surface smoothness and remove the marks left by fine grinding. Then, anti-reflection coatings are applied according to the suitable wavelengths (350nm - 2300nm) to reduce light reflection loss and enhance light transmission. After coating, adhesion tests are conducted on the coating layer to ensure there is no peeling or scratches. Finally, an initial performance check of the lens is carried out. 

Four. Processing cycle of mechanical structural parts (4-6 days) 

The mechanical structural components (such as the adjusting cylinder, guiding sleeve, lens mounting seat, etc.) need to ensure the polarization alignment accuracy and structural stability. They are processed by CNC precision machine tools, with the core control of dimensional accuracy and coaxiality. 

3. Numerical control processing (2-3 days): The ceramic and Kovar alloy substrates are processed through a five-axis CNC machine tool. The dimensional accuracy, coaxiality and thread accuracy of each component are strictly controlled (thread pitch 0.2mm, adjustment clearance 0.005-0.015mm). The adjustment cylinder is reserved with a polarization alignment adjustment structure, and the guide sleeve is equipped with a limit device. The entire process adopts thermal balance compensation technology to offset the slight displacement caused by environmental temperature differences. 

4.Surface Treatment and Inspection (2-3 days): After processing, the mechanical components undergo surface anti-corrosion treatment (gold plating, passivation) to enhance wear resistance and corrosion resistance, and remove burrs. Then, high-precision image scanning inspection is carried out, with a focus on controlling concentricity and dimensional deviation to ensure compliance with assembly requirements. Unqualified components are reworked. 

V. Precision Assembly and Polarization Alignment Debugging Cycle (5-7 days) 

This step is the core process, directly determining the polarization performance and collimation accuracy of the product. The entire process is completed in a 10,000-level clean workshop, and the alignment system for polarization-maintaining fibers is optimized to streamline the operation procedures. 

1. Pre-installation and Fixation (1-2 days): 

Pre-install the optical lenses and the processed polarization-maintaining fibers onto the mechanical structural components respectively, and fix them with optical-specific adhesive. Place the assembled components in an oven and bake them following a stepwise process (bake at 85°C for 1-2 hours and at 110°C for 2-3 hours) to ensure a firm assembly without any looseness. At the same time, conduct preliminary alignment of the optical axis and polarization direction. 

2. Polarization alignment and collimation adjustment (3-4 days): 

Utilizing polarization-maintaining fiber alignment systems and six-dimensional adjustment platforms, in conjunction with beam analyzers and CCD image recognition systems, a low-power visible alignment laser is connected. Fine-tuning the adjustment mechanism is carried out to calibrate the polarization directions of the polarization-maintaining fiber and the lens, ensuring an extinction ratio of ≥30dB. At the same time, the collimation accuracy is adjusted to ensure that the collimation accuracy is ≤0.1mrad and the coupling efficiency is ≥95%, and the adjustment parameters are locked. 

3. Sealing treatment (1 day): 

After the alignment and debugging are completed, the interior of the product is sealed to prevent dust and moisture from entering. At the same time, the assembly tightness, polarization stability, and adjustability smoothness are rechecked to ensure there is no looseness or deviation. The relevant packaging technical specifications should be followed. 

VI. Multi-dimensional Quality Inspection and Aging Test Cycle (3-5 days) 

1.Full-process quality inspection and aging tests are carried out to ensure stable product performance and compliance with factory standards, in accordance with the testing norms for optical components and polarization-maintaining devices. 

Optical and polarization performance testing (1-2 days): Test the collimation accuracy, insertion loss (≤0.3dB), return loss (≥60dB for APC interface), polarization-dependent loss (≤0.1dB), and extinction ratio. Build the test optical path using standard polarization-maintaining collimators to ensure that all parameters meet the design requirements. The testing cycle strictly follows relevant standards. 

2. Mechanical Performance and Environmental Adaptability Testing (1 day): Test the smoothness of mechanical component adjustment, the firmness of the structure, and conduct anti-vibration and anti-shock tests (in compliance with military standard GJB 150A). At the same time, perform high and low temperature cycling tests (-40℃ to 85℃, 50 cycles) to ensure no performance fluctuations. 

3. Aging Test and Final Inspection (1-2 days): Conduct short-term aging tests (72 hours) to verify the long-term stability of the product. At the same time, perform final inspections on appearance and performance parameters. Unqualified products will be reworked or scrapped, while qualified products will be numbered, filed, and equipped with test reports. 

VII. Summary and Explanation of the Overall Cycle 

The overall production cycle for standard batch production (≥50 sets) of Polarization-Maintaining Fiber Collimators is 22-32 days. The production cycle for single customized products (with special specifications, wavelengths or interfaces) can be extended by 3-7 days based on customized requirements. All process cycles have been strictly calculated and verified through practice. Relying on digital production processes and precision processing equipment, the cycle can be ensured to be stable and controllable, while also taking into account the polarization stability and collimation accuracy of the products. It is suitable for high-end application scenarios such as optical fiber communication and optical fiber gyroscopes. 

If the customer has an urgent need, they can contact our technical and production teams to optimize the production scheduling plan. Under the premise of ensuring product quality, the overall cycle can be shortened by 10% to 20%. We will provide full-cycle progress tracking services throughout the process to ensure on-time delivery.