Fused Fiber Bundles
Castor Optics’ fused fiber bundles provide a compact solution for combining multiple illumination and collection channels into a single monolithic assembly. Designed with circular symmetry and no air gaps, these structures maximize the effective collection area while minimizing the overall diameter. They are suited for high-precision and low-light sensing conditions.
These bundles are fully customizable, with a range of options for core size and numerical aperture for each fiber. Configurations can include single-mode (SMF), multimode (MMF), and double-clad fibers (DCF), tailored to meet specific application requirements. Our advanced fusion and tapering techniques also allow for control over the final structure diameter. Current configurations support up to 7 fibers.
Contact our team to explore the best solution for your optical system.
Overview
Our fused fiber bundles are engineered for advanced sensing applications, including remote environmental monitoring, high‑precision biomedical diagnostics such as fluorescence, spectroscopy, and optogenetics, and emerging quantum sensing techniques. Designed for compact or harsh environments, these bundles serve effectively as splitters, combiners, or sensing probes tailored to each use case.
What sets our products apart is their compact fused end, which is engineered to maximize the effective collection area. For instance, our 5-fiber configuration enables precise illumination through a central single-mode fiber, while four surrounding multimode fibers provide a large collection area. This setup mimics the performance of a double-clad fiber with an oversized inner cladding, offering enhanced light collection without the need for custom fiber designs. Encased in standard connectors or ferrules, our bundles provide seamless integration with existing optics, light sources, and detectors.
Nomenclature: If the same fiber type is used for all ports, they are defined as an Nx1 configuration. The configuration (N+1)x1 refers to a central illumination fiber with N surrounding collection fibers.
Key features:
- Low Insertion Loss
- Compact design and highly effective collection area
- Custom fiber configuration and packaging available
Product lines
FFB (1+1)x1, Wideband, 105 µm-0.22NA & 400 µm-0.37NA
Port A Fiber: Multimode 105 µm, 0.22 NA
Port B Fiber: Multimode 400 µm, 0.37 NA
Wavelength range: 400-1600 nm
Insertion Loss: <0.5 dB
Optimized for high collection efficiency and compact form factor, this option is ideal for applications where concentricity is not a critical requirement. Available with FC-PC or SMA905 connectors. Other fiber core sizes and NAs available, including any Double-clad fiber from our product list.
FFB (1+1)x1, 1300 nm, 8 µm-0.14NA & 200 µm-0.22NA
Port A Fiber: Single-mode 8 µm, 0.14 NA
Port B Fiber: Multimode 200 µm, 0.22 NA
SM Wavelength range: 1260-1625 nm
MM Wavelength range: 400-1600 nm
Insertion Loss: <0.5 dB
Optimized for high collection efficiency and compact form factor, this option is ideal for applications where concentricity is not a critical requirement. Available with FC-PC or SMA905 connectors. Other fiber core sizes and NAs available, including any Double-clad fiber from our product list.
FFB (2+1)x1, 1300 nm, 125 µm-0.22NA
Port A Fiber: DCF 9/105/125 µm, 0.14/0.22 NA
Ports B1-B2 Fiber: Multimode 105 µm, 0.22 NA
SM Wavelength range: 1260-1625 nm
MM Wavelength range: 400-1600 nm
Insertion Loss: <0.5 dB
Available with FC-PC, FC/APC or SMA905 connectors. Other fiber core sizes and NAs available, including any Double-clad fiber from our product list.
FFB (4+1)x1, 1300 nm, 8 µm-0.14NA & 200 µm-0.22NA
Port A Fiber: Single-mode 8 µm, 0.14 NA
Ports B1-B4 Fiber: Multimode 200 µm, 0.22 NA
SM Wavelength range: 1260-1625 nm
MM Wavelength range: 400-1600 nm
Insertion Loss: <0.5 dB
For applications requiring concentric illumination and detection with minimal dead space between fibers. The surrounding fibers can be packaged individually or in a single connector. Available with FC-PC or SMA905 connectors. Other fiber core sizes and NAs available, including any Double-clad fiber from our product list.
FFB (4+1)x1, Wideband, 50 µm-0.22NA & 105 µm-0.22NA
Port A Fiber: Multimode 50 µm, 0.22 NA
Ports B1-B4 Fiber: Multimode 105 µm, 0.22 NA
MM Wavelength range: 400-1600 nm
Insertion Loss: <0.5 dB
For applications requiring concentric illumination and detection with minimal dead space between fibers. The surrounding fibers can be packaged individually or in a single connector. Available with FC-PC or SMA905 connectors. Other fiber core sizes and NAs available.
FFB 7x1, Wideband, 200 µm-0.22NA
Ports A1-A7 Fiber: Multimode 200 µm, 0.22 NA
MM Wavelength range: 400-1600 nm
Insertion Loss: <0.5 dB
Available with FC-PC, FC/APC or SMA905 connectors. Other fiber core sizes and NAs available.
FFB 7x1, Wideband, 105 µm-0.22NA
Ports A1-A7 Fiber: Multimode 105 µm, 0.22 NA
MM Wavelength range: 400-1600 nm
Insertion Loss: <0.5 dB
Available with FC-PC, FC/APC or SMA905 connectors. Other fiber core sizes and NAs available, including any Double-clad fiber from our product list.
Available soon
Our engineering team is working on prototypes for fused fiber bundles with more than 7 fibers, such as (7+1)x1 and 19x1 compact structures. Contact us for more information.
Applications related to this product
Spectroscopy
Remote Sensing and Communication
Biomedical Imaging
Need a Custom Product?
Castor Optics offers customized options for all of available products. Please provide a detailed description of your inquiry and our team of scientists and engineers will evaluate your request.