The high-precision Coaxial Fiber Collimator

Technical Specification for High-Precision Coaxial Fiber Collimator Manufacturing 

High-precision Coaxial Fiber Collimator is a core optical component in high-end fields such as telemetry, optical communication, and precision detection. Its manufacturing process has strict requirements for material selection, processing accuracy, assembly calibration, and quality control. This technical specification elaborates on the core logic, key processes, and quality assurance system of high-precision coaxial fiber collimators, highlighting our company's technical strength in the field of optical component manufacturing and providing professional technical references for customers. 

Manufacturing core principles: 

Centered on "precise coaxiality control, optimal optical performance, and environmental adaptability matching", this principle runs through the entire process from material selection, precision processing, assembly calibration to aging tests, ensuring that the product's collimation accuracy is ≤ 0.1 mrad and coaxial deviation is ≤ 0.005 mm. This enables efficient coupling between fiber and free-space optical paths, guaranteeing the stability and low loss of signal transmission. 

I. Core Material Selection and Precise Screening (Manufacturing Foundation) 

The performance of the materials directly determines the upper limit of the collimator's accuracy and its long-term stability. It requires multiple rounds of screening and testing to ensure that each raw material meets the manufacturing standards for high-end optical devices, with a particular focus on the optical properties, mechanical strength, and environmental adaptability of the materials. 

(1) Core Optical Materials 

Collimating lens: High transmittance and low absorption loss optical materials are preferred. The type is precisely selected based on the application band - ZnSe (zinc selenide) material is chosen for the mid-infrared band (3-5um), with a transmittance exceeding 85% in this band, strong thermal stability, and good refractive index compatibility, effectively controlling the spot size and divergence angle. For the conventional band, high-purity quartz glass or sapphire is selected, ensuring a refractive index uniformity of ≤1×10⁻⁶, free of bubbles, impurities, and internal stress, to prevent beam distortion. The lens adopts plano-convex or achromatic design. The plano-convex design simplifies the optical path layout and facilitates precise control of the focal length. The achromatic design can prevent focal length drift and spot shift in broadband optical systems, suitable for multi-wavelength application scenarios. 

2. Coaxial optical fiber: 

Select single-mode or polarization-maintaining optical fiber (depending on the application requirements), with the core diameter precisely controlled (typically 9 μm), cladding concentricity deviation ≤ 0.1 μm, and loss ≤ 0.2 dB/km to ensure the integrity of optical signal transmission; the fiber end faces are precisely polished, with a roughness Ra ≤ 0.5 nm, to prevent signal attenuation caused by end face reflection, and at the same time match the optical parameters of the lens to enhance coupling efficiency. 

Structure and Auxiliary Materials 

1. Shell and base: Made of high-strength aerospace aluminum alloy or stainless steel, processed through multiple stress relief procedures, the structure has excellent rigidity and remains shape-stable over long-term use. The surface undergoes anodic oxidation or gold plating treatment to enhance corrosion resistance and electromagnetic interference resistance, making it suitable for complex environments such as aerospace and industrial telemetry. 

2. Adhesive and sealing materials: Special optical adhesives with low shrinkage and high stability are selected. After curing, there are no bubbles or cracks, and the refractive index matches that of the optical components, avoiding light axis deviation caused by bonding stress. The sealing material uses high-temperature resistant, waterproof and dustproof silicone rubber to ensure stable operation of the equipment in an environment of -40℃ to 85℃ and relative humidity ≤ 85%, preventing dust and water vapor from entering the internal components. 

3. Optical Coating: High-quality AR (anti-reflection) films are coated on the end faces of the lenses, with the passband bandwidth covering the product's compatible wavelength range. This can reduce the reflection loss to below 0.1%, significantly enhancing the light transmission rate, reducing the waste of light energy, and ensuring the stability of the collimation performance. 

Key Manufacturing Processes (Precision Core Assurance) 

The core of manufacturing high-precision coaxial fiber collimators lies in "precisely controlling the error of each link". Through precise processing, accurate assembly and strict calibration, the coaxiality of the fiber, lens and housing is precisely matched. The core process is divided into four major links. 

(1) Precision Processing of Optical Components 

Lens processing: Utilizing ultra-precision diamond turning and polishing techniques, the processing accuracy is controlled at the nanometer level. The surface flatness of the lens is ≤λ/20 (λ=632.8nm), the radius of curvature tolerance is ≤±0.001mm, and there are no chipped edges or scratches on the periphery. After processing, the surface quality and optical parameters are inspected through professional optical testing equipment (such as interferometers). Unqualified products are directly eliminated to ensure that each lens meets the optical performance requirements. 

2. Fiber optic end face processing: 

Utilizing precise grinding and polishing techniques, the fiber optic end face is polished to a mirror-like finish, with an end face perpendicularity of ≤0.1°, to prevent light axis deviation caused by end face tilt. At the same time, the fiber optic is cleaned to remove surface impurities and oil stains, ensuring no impact on subsequent coupling performance. 

3. Shell and base processing: 

Utilizing a CNC precision machining center, high-precision processing of the inner holes and installation grooves of the shell is achieved, with the roundness of the inner holes ≤ 0.001mm, coaxiality ≤ 0.002mm, and flatness of the installation surface ≤ 0.001mm. After processing, deburring and cleaning are carried out to ensure there are no impurities or burrs inside and to prevent scratches on optical components. 

II.High-Precision Coaxial Assembly 

The assembly process is the key to controlling coaxiality and must be carried out in a 10,000-level clean workshop. The entire process adopts dust-free operation to prevent dust and impurities from affecting product performance. The core steps are as follows: 

1. Positioning reference calibration: 

Taking the inner hole of the shell as the reference, the installation positions of the lens and the optical fiber are determined through a high-precision positioning fixture (positioning accuracy ≤ 0.001mm), ensuring the initial alignment of their optical axes. An XYZ + θz four-dimensional adjustment frame is used to achieve integrated adjustment of three-axis translation and 360° rotation around the optical axis, completely eliminating inter-axis crosstalk and ensuring zero eccentricity and zero displacement of the optical axis. 

2. Lens assembly:

Qualified lenses are installed into the housing. The position of the lenses is finely adjusted through a precise adjustment mechanism. The path of the light beam is monitored in real time with a CCD image recognition system and a beam analyzer to ensure that the optical axis of the lens is completely aligned with the center axis of the housing, with a deviation of no more than 0.002mm. After the adjustment is completed, the lenses are fixed with optical-specific adhesive. During the curing process, the offset of the optical axis is monitored in real time to ensure that there is no stress deformation after curing. 

3. Fiber assembly: 

Insert the processed coaxial fiber into the base, adjust the distance between the fiber end face and the lens (precisely control the air gap), monitor the coupling efficiency through a precision coupling device, and fine-tune the fiber position to ensure the coupling efficiency is ≥ 95% and the signal attenuation is ≤ 0.3 dB. After fixing the fiber, recheck the coaxiality to ensure the deviation between the fiber and the lens optical axis is ≤ 0.005 mm, avoiding a decrease in collimation accuracy due to fiber offset. 

Optical Calibration and Alignment 

Calibration and debugging are the core steps to enhance the collimation accuracy. Professional calibration equipment is adopted to achieve precise calibration of multiple parameters, ensuring that the product performance meets the standards. 

1.Collimation accuracy calibration: 

Connect the assembled collimator to a standard optical signal, monitor the spot shape, parallelism and divergence angle of the collimated beam through a beam analyzer, and fine-tune the relative position of the lens and the fiber to ensure that the collimation accuracy is ≤ 0.1 mrad, the spot ellipticity is ≥ 90%, and the beam parallelism meets the requirements of high-end applications. 

2. Coaxiality recheck: 

A laser interferometer and a CCD image recognition system are used to recheck the coaxiality of the optical fiber, lens, and housing, ensuring that the overall coaxial deviation is ≤ 0.005mm. For the dedicated collimator for telemetry, an additional optical path coupling test is conducted to simulate the actual application scenario, ensuring that it can maintain precise coaxiality even in complex environments. 

3. Performance parameter debugging: 

Test the product's wavelength adaptation range, power carrying capacity, signal transmission loss and other parameters to ensure they are in line with the design standards; conduct personalized parameter debugging for different application scenarios (such as aerospace, industrial telemetry) to meet customers' customized demands. 

4.Solidification and Encapsulation Process 

1.Curing process: Place the calibrated collimator into a constant-temperature curing box and adopt a stepwise curing process. Control the curing temperature (80°C to 120°C) and time to ensure that the optical adhesive is fully cured without any bubbles or cracks. At the same time, prevent stress from being generated during the curing process, which could cause the optical axis to shift. 

2. Sealed Encapsulation: Utilizing a waterproof and dustproof sealing process, the interfaces of the outer casing and the fiber optic lead-out ends are sealed to prevent the intrusion of dust, moisture, and corrosive gases. After the encapsulation is completed, a gas tightness test is conducted to ensure no leakage under high pressure and high humidity conditions, thereby enhancing the product's environmental adaptability. 

3. Surface treatment: Clean and polish the product shell, affix the product nameplate (including parameters such as wavelength, collimation accuracy, and power), ensuring the product's appearance is neat and the markings are clear, in compliance with industrial product standards. 

Full-process Quality Control System (Quality Assurance) 

To ensure the stable performance and reliable quality of each high-precision coaxial fiber collimator, a full-process quality control system from raw material selection to finished product delivery has been established. We strictly adhere to the ISO9001 quality management standard. The key control points are as follows: 

1. Raw Material Inspection 

All raw materials must undergo professional testing before being admitted to the warehouse: optical materials are tested for transmittance, refractive index and surface quality; structural materials are tested for mechanical strength, dimensional accuracy and corrosion resistance; auxiliary materials are tested for bonding strength, curing performance and environmental adaptability. Unqualified raw materials are strictly prohibited from being admitted to the warehouse to control product quality from the source. 

Process Inspection 

After each manufacturing process is completed, a dedicated inspection is carried out: the surface quality and dimensional accuracy of the lens are inspected after optical processing; the coaxiality and coupling efficiency are inspected in real time during assembly; the offset of the optical axis and the stability of the bonding are inspected after curing. If any process is not up to standard, rework or scrapping is required to prevent the accumulation of errors. 

III.Comprehensive Inspection of Finished Products 

Before leaving the factory, the finished products undergo comprehensive performance testing. The core testing items include: coaxiality (≤0.005mm), collimation accuracy (≤0.1mrad), coupling efficiency (≥95%), signal attenuation (≤0.3dB), environmental adaptability (high and low temperature, humidity, and vibration tests), and airtightness test. A patented detection method is adopted, with a standard collimator as the benchmark. The spot size information is collected by a camera, and the divergence angle and ellipticity are calculated to determine the product's qualification. Only after passing the tests can the products be released from the factory. 

Aging Tests and Reliability Verification 

Select some finished products for long-term aging tests, simulating actual application environments (high and low temperature cycles, vibration, humidity changes), and continuously monitor the performance changes of the products to ensure that the collimation accuracy and coupling efficiency do not significantly decline during long-term use (service life ≥ 5 years). At the same time, conduct impact tests and anti-electromagnetic interference tests to verify the reliability of the products under complex working conditions, meeting the usage requirements of high-end scenarios such as aerospace and industrial telemetry. 

IV. Manufacturing Technology Advantages and Application Adaptability 

1.With years of experience in the manufacturing of optical components, our company has developed core technical advantages in the field of high-precision coaxial fiber collimators, ensuring that the performance of our products remains at the forefront of the industry. 

Precision control advantage: 

By using the four-dimensional adjustment frame and laser interferometer linked calibration technology, the coaxiality and collimation accuracy can be controlled at the nanometer level, with an error within 0.001mm, far exceeding the industry's conventional standards. 

2. Material compatibility advantage: 

According to the application band of the customer (350nm - 2300nm), optical materials and coatings can be precisely selected to adapt to different scenarios such as mid-infrared and conventional bands, meeting the demands of multiple fields including remote sensing, optical communication, and precision detection. 

3. Stability Advantage: 

Through full-process stress control and aging tests, the product has strong environmental adaptability and can operate stably in complex environments such as -40℃ to 85℃, strong electromagnetic interference, and vibration, with low signal transmission loss and high stability. 

4. Customization Advantage: 

According to the specific requirements of customers, the size of the lens, the type of optical fiber, interface specifications (such as SMA, BNC, FC/PC), and performance parameters can be customized. We provide exclusive manufacturing solutions to meet the personalized needs of different scenarios. 

The manufacturing of high-precision coaxial fiber collimators is a perfect combination of optical technology, precision processing and quality control. Our company has always adhered to the concept of "precise manufacturing and quality first", and with strict process standards, advanced manufacturing equipment and a complete quality system, we provide high-performance and highly reliable coaxial fiber collimators for global customers, contributing to the technological upgrading and industrial development of the high-end optical field. If you need to know more about manufacturing details, customized solutions or technical parameters, you can contact our technical team for exclusive support.