New Broad Spectrum Fiber for Industrial Fiber Sensing Applications
DOWNLOAD PDF
Authors: John Shannon, Rick Timmerman and Valery Khalilov
Introduction
In the field of fiber sensing, many industrial applications require the capability to measure optical signals across a very wide spectral range. Historically, optical fibers have been limited in their transmission spectral range. Fibers with high OH content perform better at UV wavelengths, however, the OH content creates very large absorption regions in the Near Infrared (NIR) wavelengths. Conversely, fibers with low OH content can perform very well in the NIR region of the spectrum, but tend to have very poor UV performance. Both types of traditional fibers transmit well in most of the visible spectrum.
The New FBPI Fiber
A new silica-based fiber design has been developed at Polymicro Technologies which exhibits improved transmission properties over a very wide spectral range. This fiber is known as FBPI fiber and can be produced in core diameters from 50μm to 600μm. In the near infrared wavelength region to beyond 2100nm, the attenuation of the new fiber is similar to standard low OH fibers. Simultaneously, the fiber has excellent UV transmission down to 200nm comparable to standard high OH fibers.
Another important characteristic of optical fibers is its resistance to solarization damage caused by exposure to high levels of UV illumination. In the case of the new FBPI fiber, the UV-defect concentrations have been reduced significantly, such that the solarization degradation properties are close to UV optimized high OH fibers with high radiation resistance.
Broad Spectral Performance
Below is a chart of the spectral attenuation performance for four separate fiber types for comparison. The fiber types are:
-
FIP- Standard low OH core for near IR
- FVP- Standard high OH core for UV/Visible
- FBP- Existing broad spectrum fiber, not optimized for near IR attenuation or UV solarization resistance
- FBPI- New broad spectrum fiber, optimized for near IR attenuation and UV solarization resistance
As can be seen in the chart, the new FBPI demonstrates the optimum performance of high OH fibers in the UV and low OH fibers in the near IR.
UV Solarization Resistance
In order to evaluate the resistance to solarization caused by exposure to high levels of UV light, a “4 Hour UV Exposure Test” is performed. This test is performed by taking a prepared two meter length of the test fiber and coupling it to a high output deuterium lamp source. The output of the fiber is monitored using a UV spectrometer over a period of four hours. The results of this test are shown in the chart below, with the induced attenuation for the two meter section given for six separate wavelengths in the UV region.
The FBPI exhibits a low level of induced attenuation. Additionally, the induced attenuation stabilizes to a saturation level after a short time period for each of the tested wavelengths.
Summary
Polymicro Technologies has developed a new broadband fiber which exhibits the UV performance of a high OH fiber and the near IR performance of a low OH fiber. This fiber is optimized for sensing applications where extremely wide spectral performance is required. In addition, excellent UV solarization resistance has been demonstrated.
# # #
Polymicro Technologies,
A subsidiary of Molex Incorporated
18019 N 25th Ave., Phoenix, AZ
85023-1200
Ph: 602-375-4100
Fax: 602-375-4110
www.polymicro.com
Media Contact:
602-375-4100
|
