High-Precision Micro C-lens for Efficient Laser Alignment

Application:

Optical communication, fiber sensors, laser modules, optical testing, and photonic devices require precise beam collimation.

Products / Modules Include:

• Line Isolator
• FWDM / CWDM / DWDM
• Circulator
• Switch
• 100G–800G Optical Subassemblies
• Laser Modules
• Optical Alignment & Testing Modules

Basic specifications:

• Materials: N-SF11, 7980, JGS1, N-BK7, silicon, etc.
• Minimum outer diameter: 0.49mm
• Minimum length: 0.4mm (for outer diameter 1.0mm)
• Curvature: Infinite (current maximum R88.15)
• Right-angle surface angle: Customize from 0° to 15°, with angle tolerance of 0.5°
• Damage threshold: Meets >25J

The engineering benefits of the Collimating Lens (C-Lens)

1. In-depth customization of optical capabilities

Hobbite supports full-process optical customization from materials, geometries, to coating solutions, covering the UV, VIS, NIR bands, and providing aspherical and microcylindrical structures, special angle of incidence designs from 0–15°, and SM/MM/PM fiber interface moduleization. Each lens can be fine-tuned according to the customer’s actual optical path to suit different system requirements.

2. Independent processing capacity of the whole process

We have a complete in-house process chain from coarse grinding, fine grinding, polishing to coating, including CNC optical machining, ultra-smooth IBF harvesting, high-damage threshold optical coating, and geometry machining capabilities in the 2 μm level. The advantage is that it maintains higher consistency and stability on small optical components.

3. Complete measurement system

All products are strictly measured before leaving the factory by interferometer wavefront detection, surface shape error and roughness scanning, and a traceable full-scale recording system. Complete inspection data can be used directly for quality audits, system modeling, and performance validation.

4. Joint engineering support

Each project is provided by a team of experienced engineers at the system level, including focal length selection, beam divergence control, coating optimization, installation structure design, and optical path alignment solutions. It is suitable for OEM batch projects and R&D trial production stages, achieving efficient development and rapid implementation.

What is C-Lens?

C-Lenses (also often referred to as Fiber Collimation Lenses) are essentially a class of miniature collimating lenses with a flat side on one side and a specific curvature on the other. Its curvature is precisely engineered to closely match the numerical aperture (NA) and divergence angle of the fiber end face, resulting in stable, low-loss beam shaping. Compared with conventional spherical or cylindrical lenses, the optical surface shape of C-Lens is more suitable for the near-field characteristics of optical fiber paths, so it is widely used in optical communication, laser processing, and sensing modules.

Core Functions of C-Lens

1. Collimate the divergent beam of the fiber optic endface

The optical fiber output is a typical Gaussian divergent beam, and if not finished, the spot will rapidly increase, and the energy density will decrease with distance.
The C-Lens converts this divergent beam into a low divergence angle or even near-parallel light with a curvature that matches the fiber NA, making it easier to work with the backstage lens or coupling element and significantly reducing the optical path footprint.

2. Used to improve spot compression and coupling efficiency in laser modules

In laser modules such as LD and VCSER, due to the large and asymmetrical divergence angle of the chip, the spot needs to be “shaped” first to make it more directional and uniform when entering the post-collimation system.
A well-designed C-Lens can control spot size at the micron scale, improving coupling efficiency with fiber, detector, or microlens arrays while reducing reliance on mechanical positioning accuracy.

3. Provides stable angle of incidence control and better wavefront quality

Because the C-Lens is close to the fiber endface, its optical path is virtually unaffected by external disturbances, providing a predictable, stable angle of incidence that keeps the beam consistent as it enters the post-level system (e.g., filters, WDMs, collimator modules).
The curvature and surface quality of the lens also significantly improve the wavefront shape and reduce local distortion, making it easier for the system to achieve the desired spot morphology.

4. Reduce multi-class aberrations and improve alignment tolerance

C-Lens can compensate for spherical aberrations and coma caused by fiber characteristics or module structure.
This results in looser tolerances across the system and reduced sensitivity to thermal drift, mechanical displacement, and angular deviations, improving module consistency in mass production.

Important Notes

Collimation itself changes the energy distribution of the beam, especially when the Gaussian beam transitions to approximately parallel light, where the edge energy ratio may be slightly adjusted. Therefore, in the optical design stage, the following factors need to be considered:

• Focal length (f): affects the divergence angle and spot size after collimation
• Numerical aperture (NA): the degree of matching with the fiber determines the coupling loss
• Refractive materials: glass dispersion and transmittance affect the performance of different wavelengths
• Coating Scheme: AR films are crucial for specific wavelength reflectance

Only when these parameters are carefully weighed can C-Lens perform optimally in real-world optical communications, laser modules, or sensing systems.

Types of C-Lenses / Collimation Lenses

Classification by structure

• Plano-convex/biconvex structure: conventional collimation, cost-friendly
• Achromatic structure: designed for broadband light sources
• Aspherical C-Lens: Smaller aberrations and more stable collimation
• Reflective collimator: suitable for a wide range of UV/IR bands

Classification by module configuration

• Stationary collimator (stable, factory calibrated)
• Adjustable collimator (suitable for R&D)
• Fiber Optic Collimators (FC/APC, FC/PC, SMA, etc.)

Why Hobbite?

• Strong mass production stability: more than 250 million small optical parts have been shipped cumulatively
• High processing consistency: geometric size, curvature, and coating are strictly controlled by batch
• Reliable ability: standard parts in stock + high level of customization
• Focus on module-level applications: support customers to optimize the structure of the whole set of optical modules
• International customer verification: long-term cooperation in communications, laser, medical and other industries

Frequently Asked Questions (FAQs)

Q1: Can C-Lens be used for both single-mode and multimode fibers?
OK. We adjust the curvature and focal length according to the difference in fiber aperture so that both fibers can achieve stable collimation.

Q2: Are there any models in stock?
We retain some of the standard-sized Collimating lenses for rapid customer testing.
If you need to customize, please contact our professional consultants for the general delivery time.

Q3: Can you do coating for specified wavelengths?
OK. UV, visible, and near-infrared bands can all be customized according to the actual wavelength.

Q4: What is the level of tolerance and surface quality of the lens?
Dimensional tolerances up to ±2 μm, surface roughness <5 nm, and wavefront quality λ/4–λ/10 according to customer requirements.

Q5: Do you support a large quantity supply?
In the tank. Hobbite has long-term high-volume optical communication customers with stable processes and sufficient production capacity.

Contact Us

For consultation, quotation, or custom design, please contact the technical team. We support you in selecting the right products, offering coating solutions, and systems integrations to reach the best possible performance in your optical system.