There are basically two types of multi-mode fibers: graded-index fibers and step-index fibers. In step-index fibers, the refractive index decreases dramatically between the core and the cladding. They are available as quartz/quartz fibers or as so-called HCS fibers (with a quartz core and a plastic cladding). In graded-index fibers, however, the refractive index decreases steadily with increasing radial distance from the fiber axis.
Long life, deep UV transmission is possible with Polymicro’s solarization resistant optical fibers.
Solarization is a change in material characteristics due to illumination of a material with ultraviolet (“solar”) light. High intensities of UV illumination can cause photo-thermal damage in quartz optical fibers, dramatically increasing the scattering and attenuation.
The breakthrough in fiber technology allows optical fibers to be used with deuterium lamps and a wide variety of deep UV laser sources. This fiber overcomes the age-old problem of UV induced color centers around 210 nm - 214 nm. It is ideal for deep UV spectroscopy, lithography, and excimer laser delivery systems.
Fiber core sizes can be produced from 50 mm to greater than 1000 mm. Custom cables or assemblies are available.
Recently, with the availability of a modified core preform, a new fiber became available designated as UVM. This fiber provides long term stability, but at a cost of some transmission.
By combining hydrogen loading and the modified core material designated as UVMI, advantages are seen that provide the excellent performance of hydrogen loading and, if over time the hydrogen loading is lost by diffusion, the fiber will revert to the characteristic UVM performance.
New is the FDP fiber. The FDP fiber undergoes a series of proprietary processing steps and offers excellent solarization resistance without the concerns related to Hydrogen diffusion. It has excellent lifetime and superior long term stability with only minimal initial attenuation loss. It is the fiber of choice for most deep UV applications, especially when smaller diameter fiber is required.
To simplify the product line, Polymicro is currently offering: