#Glass preform software#

Important equipment considerations to achieve design goalsĪs an operator, what can you do to make sure you meet your design goals? As discussed, you must tightly control the barrier layers and depressed well layers. The depressed well thickness must be carefully designed to prevent main mode cutoff. This design increases the refractive index difference between barrier and core layers without increasing core germanium and increases the NA. The depressed well layers can be formed with dopants like fluorine. One tactic is to reduce the refractive index of the high-purity barrier layers around the core. However, the more you add, the higher your fiber losses become.

Depressed well (index < silica) barrier layers (to minimize core GeO2) can be used to minimize core glass losses – MCVD operators know that germanium in cores increases the refractive index.

If the barrier layer isn’t thick enough, the mode field may encounter the deposition tube glass, with potential absorptions or reflections leading to increased fiber loss. Some light may be guided in the barrier layer depending on the optical design. The pure glass is important because, depending on the waveguide design, the mode field traveling through the fiber’s core will expand depending on wavelength. You typically deposit several layers of high-purity glass inside the substrate tube to form a pristine surface for your critical deposition layers, which will guide light.

Barrier layers slow OH migration, provide high-purity glass substrate for critical deposition layers, and create pure glass for expanding mode fields – As you know, the glass barrier layers are typically index matched to the starting tube but have much higher purity.

As an operator, this gives you vital information to plan MCVD process changes that will meet specified design goals.

#Glass preform software#

Typically, the profiler has software to predict the drawn fiber’s cutoff wavelength, MFD, and NA. This is critical information to analyze the completed preform and predict the ability to meet design goals. The preform profiler is critical to meeting design goalsĪs an MCVD operator, you rely on the profiler to measure the completed preform’s refractive index and dimensions, such as the thickness of glass layers. The following paragraphs offer a high-level review of critical design goals for optical fiber preforms, along with tips for MCVD operators to manufacture the specified glass waveguides and achieve reproducible designs. In addition to resolving design issues with the designer, the MCVD operator must tightly control multiple equipment and process variables throughout the fabrication process.

The “blueprint” may look great on paper, yet the two professionals need to work closely together to figure out real-world specifics. In fact, the preform fabrication’s designer/operator team is similar to how architects and homebuilders work together. In my years of operating and maintaining an MCVD fabrication system at 3M, I worked closely with the designers and was intimately involved in the design process to ensure designs were manufacturable in regard to expansion coefficients and so forth. Additional waveguide design fabrication goals include high purity, low OH, uniformity, and reproducibility. In addition, there are many design tactics to meet cutoff wavelength, mode field diameter (MFD), and numerical aperture (NA). Low metallic impurities prevent reflective loses, and dry raw materials prevent absorptions. As we all know, high-purity raw materials are critical to achieve design goals.