Step Index Plastic Cladding Hight Numerical Aperture(BGHP)

Step-index plastic-clad large numerical aperture silica fiber (BGHP) | High NA 0.37-0.48 | Core diameter 100-1000µm | High-efficiency coupling

The BGHP series of optical fibers employs a step-index multimode structure, with a high-purity synthetic silica core and a low-refractive-index polymer cladding (silicone resin or fluorinated acrylate), making it a typical plastic-clad silica fiber (PCS). Leveraging its large core (100–1000µm) and high numerical aperture (0.37–0.48), it can capture incident light at extremely wide angles, significantly improving coupling efficiency with light sources such as LEDs and laser diodes, and allowing the use of low-cost fiber optic connectors.

The operating wavelength covers 300–2400nm, offering both high-OH and low-OH versions optimized for ultraviolet-visible and near-infrared-shortwave infrared light, respectively. Polyimide or ETFE buffer layers are optional, making it suitable for harsh environments such as medical sterilization and high-temperature industrial applications.

Product Advantages

1. Ultra-high Numerical Aperture & Ultimate Coupling Efficiency

NA 0.37–0.48, far exceeding conventional 0.22 fiber. A wider beam-gathering angle effectively captures the power of high-divergent light sources such as LEDs, VCSELs, and laser diodes, allowing for low-cost, high-tolerance connectors and reducing overall system costs.

2. Large Core 100–1000µm & High Power Tolerance & Wide Spectral Coverage

The large core diameter reduces power density, supporting laser transmission from tens to hundreds of watts (1064nm CW damage threshold >1.3 kW/mm²). High OH version (220–1100nm) optimizes for UV/Vis light, while low OH version (350–2400nm) optimizes for near-infrared/short-wave infrared.

3. Biocompatibility & Multiple Sterilization Methods • Medical-Grade Reliability

The synthetic quartz core with silicone cladding is biocompatible and can be sterilized via ETO, high-pressure steam, electron beam, and gamma radiation. High tensile strength (≥70 kpsi) makes it suitable for repeated sterilization.

4. Wide Temperature Range & Strong Chemical Stability

The silicone cladding reaches -40℃ to 180℃, while the polyimide coating extends to -190℃ to 385℃. A secondary epoxy and Teflon coating enhances chemical resistance.

Applications:

• Spectral analysis, photo genetics and medical diagnosis
  
• Optical fiber lighting, optical fiber temperature measurement, medium distance communication
  
• High power energy laser
  

Geometry & optical characteristics:

• Multiple core diameters can be chosen 100 / 200 / 300 / 400 / 600 / 800 / 1000 um
  
• The ratio of cladding to core is about 1: 1.1.
  
• Numerical aperture of NA 0.37-0.39
  

BGHP Optical fiber structure:

BGIR Optical Fiber selection reference Table:

Advantages of Step-Index Plastic-Clad Fiber Design

1. Large Numerical Aperture Principle

NA = √(n_core² − n_clad²). The refractive index of the plastic cladding (~1.41) is much lower than that of the quartz core (~1.458), creating a large refractive index difference. NA can reach 0.37–0.48, far exceeding that of all-quartz fiber. High NA allows for a larger receiver cone angle, simplifying optical path alignment with high divergence angle light sources.

2. High OH / Low OH Quartz Selection

High OH (High Water Peak): Hydroxyl content approximately 700–1200 ppm, better UV transmission, suitable for 220–1100 nm.

Low OH (Low Water Peak): Hydroxyl content ≤0.5 ppm, eliminates the 1380 nm water peak, suitable for 350–2400 nm.

(FAQ)

1. What are the main differences between BGHP and all-quartz fiber (AS)?

PCS offers higher NA (0.37–0.48) and larger core diameter, resulting in high coupling efficiency and low cost, making it suitable for short-distance, high-power transmission. All-quartz fiber has lower attenuation, making it suitable for long-distance communication.

2. What are the differences between PCS and plastic fiber (POF)?

POF is all polymer, with extremely low cost but high attenuation and short range (<100m). PCS has a quartz core and plastic cladding, combining the advantages of low attenuation and high NA.

3. How to choose between high OH and low OH?

Main wavelength 200–1100nm (UV laser, visible light) → High OH.

Main wavelength 800–2400nm (Near-infrared laser, infrared sensing) → Low OH.

4. Sterilization methods?

ETO, high-pressure steam (limited to high-temperature buffer layers), electron beam, gamma radiation.