Step Index High-OH Ultraviolet Light Optimized Fiber(BGUV)

Step Index High-OH Ultraviolet Light Optimized Fiber(BGUV)

The BGUV series optical fibers employ a step-index multimode structure, combined with a unique 'high water peak' process (retaining the 1380nm OH⁻ absorption peak), significantly reducing color center defects (photodarkening) caused by ultraviolet irradiation. Compared to traditional low-water-peak silica fibers, BGUV exhibits more stable transmittance under continuous ultraviolet laser (e.g., 266nm, 355nm) or high-pressure mercury lamp environments. With a numerical aperture of 0.22, it supports various core diameters from 100µm to 1000µm and is compatible with standard connectors such as SMA905, FC, and ST, making it an ideal transmission medium for ultraviolet curing, ultraviolet laser medical applications, and spectral analysis.

Core Advantages

1. High Water Peak & UV Enhancement Mechanism: Conventional low water peak fibers are prone to developing non-bridging oxygen holes and other color centers under UV irradiation, leading to darkening. BGUV intentionally retains a high water peak at ~1380nm (OH⁻ content approximately 800–1500ppm), where hydroxyl groups bind to defect sites, suppressing color center formation. Actual measurement: Loss increment after 200 hours of continuous 266nm laser irradiation <0.08dB/m.

2. Step-Index Multimode Design: Precisely controlled step refractive index distribution supports high-power UV transmission with large core diameters (100–1000µm). Numerical aperture NA 0.22 ±0.02, high coupling efficiency, uniform mode scattering, and avoidance of hotspot effects.

3. Superior UV Radiation Resistance: Through special fluorine doping and annealing processes, the transmittance retains >95% (5000-hour accelerated aging test) under long-term irradiation by UV laser diodes, excimer lasers (248nm, 308nm), and UV LEDs.

4. Wide Temperature Range and High Mechanical Strength: Operating temperature -40℃ ~ +150℃ (acrylate coating) or -55℃ ~ +300℃ (polyimide coating). Dynamic fatigue parameter Nd ≥ 28, short-term bending radius as low as 15mm (for small core diameters), meeting the requirements of flexible wiring.

Applications

Ultraviolet Laser Processing (355nm, 266nm Q-switched/nanosecond laser transmission)

Ultraviolet Curing Systems (UV LED, High-Pressure Mercury Lamp Guides)

Spectrometers and Ultraviolet Water Quality Analysis (Fiber Optic Probes)

Semiconductor Testing and Lithography Equipment

Medical Ultraviolet Beam Guiding (308nm Excimer Laser Treatment)

Ultraviolet Fiber Optic Sensing (Ultraviolet Radiation Monitoring)

Research-Grade Ultrafast Ultraviolet Pulse Transmission

Security Ultraviolet Raman Spectroscopy Systems

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 0.22
  

High-OH fiber attenuation curve:

BGUV Optical Fiber selection reference TableTe:

Standard length: 500 meters/reel, custom cutting available.

Optional end connectors: SMA905, FC, ST, D80, etc.

UV patch cords and branched fiber bundles are available.

Why is a high water peak beneficial for ultraviolet transmission?

In ordinary silica optical fiber, manufacturers try to minimize the water absorption peak at 1380nm to achieve low loss across the entire wavelength range. However, for UV-optimized fibers, retaining a moderate water peak (high water peak) can actually neutralize the color center precursors generated by ultraviolet irradiation. BGUV, by precisely controlling the hydroxyl concentration, allows OH⁻ to interact with defects such as dangling bonds and oxygen vacancies in the silica network, thereby significantly mitigating the UV-induced 'eclipse effect.' Actual measurement data shows that after 1000 hours of irradiation with a 248nm KrF excimer laser (20mJ/cm², 500Hz), BGUV retains 92% transmittance, while conventional low-water-peak ultraviolet fiber retains only 70%.

(FAQ)

1. Will high water peak UV fiber affect visible or near-infrared performance?

BGUV is primarily optimized for the UV band. It still has moderate transmission efficiency (approximately 70%/meter) in the visible light (400–700nm), but experiences higher absorption loss in the near-infrared region due to the water peak. Therefore, it is best suited for pure UV or UV-Vis hybrid applications and is not recommended for near-infrared-dominant systems.

2. What is the core difference between BGUV and ordinary UV multimode fiber?

Ordinary UV multimode fiber typically uses a low water peak design, neglecting the accumulation of color centers under long-term UV irradiation, resulting in severe darkening. BGUV intentionally retains a high water peak, significantly improving the UV damage threshold, and its step-index refractive index ensures mode stability.

3. Can it be used for high-power excimer lasers (308nm / 248nm)?

Yes. A core diameter of 400µm or larger is recommended, combined with a polyimide coating, to support peak power in the MW/cm² range. For detailed power thresholds, please consult the technical manual or conduct actual tests.

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