Fiber core for a 1-to-2 optical splitter

The fiber core for a 1-to-2 optical splitter typically ranges from 50 µm to 200 µm for multimode fibers, while single-mode splitters use cores around 8–10 µm, depending on the application and wavelength.

Fiber Core Considerations

Single-mode fibers (SMF) have a core diameter of approximately 8–10 µm, optimized for long-distance, low-loss transmission at wavelengths like 1310 nm or 1550 nm. They are commonly used in FTTH networks, data centers, and enterprise LANs where precise signal splitting and minimal insertion loss are critical . Multimode fibers (MMF) have larger cores, typically 50 µm or 62.5 µm, suitable for short-distance applications, laboratory setups, or high-power light delivery. Large-core fibers, such as 200 µm, are used in spectroscopic or industrial applications where higher light throughput is needed .

Splitter Types and Core Compatibility

1. Fused Biconical Taper (FBT) Splitters: Fabricated by fusing and tapering fibers together. They support both SMF and MMF, but insertion loss and wavelength sensitivity vary. MMF FBT splitters often use 50–200 µm cores .
2. Planar Lightwave Circuit (PLC) Splitters: Typically single-mode, with fixed uniform splitting ratios. Core size is standard SMF (~8–10 µm), suitable for high fiber counts and broadband applications .
3. Filter-Type Splitters (TFF): Use thin-film filters to separate wavelengths. Core size matches the input fiber, usually SMF for telecom wavelengths, ensuring low insertion loss and precise wavelength separation .

Practical Recommendations

• For telecom or FTTH applications, use single-mode 8–10 µm cores with PLC or filter-type 1×2 splitters.
• For laboratory or high-power light applications, multimode 50–200 µm cores are preferred, especially when using fused fiber splitters for spectroscopy or sensor systems .
• Ensure the core size matches the input fiber to minimize coupling loss and maintain signal integrity.
• Consider the wavelength range and splitting ratio when selecting the splitter type, as these affect insertion loss and performance. By selecting the appropriate fiber core size and splitter type, you can achieve efficient 1-to-2 light distribution with minimal loss and optimal performance for your specific application .