Specialty optical fiber fabrication: preform manufacturing based on asymmetrical CO laser heating

Abstract

Here, we present an innovative preform manufacturing technique for specialty optical fibers based on a carbon monoxide laser heating a rotating preform. The setup performance is evaluated with the aid of finite element modeling. The fabrication process is described in detail using silicon core preforms as a benchmark. The hybrid material nature of such a preform is addressed, together with the relevant characteristics, such as the difference in thermal conductivity and thermal expansion. Silicon core preforms with a wide range of core sizes were manufactured, proving the viability of this system for the development of specialty optical fibers based on novel materials.

Advances in laser‐based manufacturing techniques for specialty optical fiber

“…With these advantages in consideration, a CO laser (λ ≈ 5.5 µm) represents a suitable source. It was successfully utilized by Oriekhov et al and Harvey et al in preform making 110 and lab-scale draw tower, respectively. 71 In the 2-m tall draw tower described in detail in Harvey et al, 71 the laser-based furnace consisted of four beams obtained by splitting the primary beam with a diffraction grating.…”

“…Due to these benefits, laser-based heating is broadly used in fiber fabrication and post-processing. 110,[113][114][115][116][117][118][119]…”

“…and Harvey et al. in preform making 110 and lab‐scale draw tower, respectively 71 . In the 2‐m tall draw tower described in detail in Harvey et al., 71 the laser‐based furnace consisted of four beams obtained by splitting the primary beam with a diffraction grating.…”

“…Moreover, the rapid temperature control and open architecture of laser‐based furnace allow for faster process monitoring and feedback. Due to these benefits, laser‐based heating is broadly used in fiber fabrication and post‐processing 110,113–119 …”

Specialty fiber fabrication using carbon monoxide laser heating

“…Preforms were prepared using a rod-in-tube approach, with fused silica inserts at each end of the core rod. 8 Figure 1a shows an example of a camera view of the neckdown region during fiber draw of a silica core fiber (preform diameter 6 mm, core diameter 1 mm), with Fig 1b and c showing micrograph of drawn fiber with a silicon core diameter of 20 µm and 1.3 µm, respectively. The CO laser based draw tower is easy to operate and draw speeds above 30 m/min have been achieved.…”