Polysilane Optical Fiber
Original Publication Date: 2003-Dec-03
Included in the Prior Art Database: 2003-Dec-03
Polymer photonic crystal hollow-core fibers are drawn by forcing a viscous polymer solution of polysilane through a spinneret orifice. The pattern of the orifice has a large centered hole, which corresponds to the hollow-core, and many small holes, which form a two-dimensional photonic crystal lattice. Each of the holes is connected to pressurized N2 gas. The pressures are regulated to different pressures to obtain the desired photonic crystal hole pattern. The drawn polymer fiber passes through hot zones for a pre-bake process and a post-bake process. Through these processes, the polymer becomes a silica-like photonic crystal hollow-core fiber.
Polysilane Optical Fiber
Disclosed is a polymer optical fiber and its fabrication process for short span optical data transmission, such as optical interconnects for computers. Although the optical absorption losses in polymer fibers are greater than those of quartz optical fibers, polymer photonic crystal hollow-core fibers1) are expected to have smaller absorption losses than conventional bulk optical fibers, because their optical fundamental modes are not located in the polymer part but in the hollow portions, which are naturally filled with air.
The fabrication method so far reported is fiber drawing using a polymer preform, which is a stack of polymer tubes.2) This fabrication method is intrinsically expensive and does not scale well for mass production. In this disclosure, polymer photonic crystal hollow-core fibers are fabricated without using preforms but made by using a continuous drawing of fibers from a spinneret capillary orifice similar to a nylon fiber melt spinning process.3)
Poly(methylphenylsilane) is dissolved in toluene and forms a high-viscosity polymer solution. The solution is ejected into the air from a metal spinneret orifice, which corresponds to the form to produce the polymer photonic crystal hollow-core fiber shown in Fig.1. The large hole in the center of the fiber is the fiber hollow-core, and the small holes are the two-dimensional photonic crystal lattice for 850 nm light.
Figure 2 shows a schematic cross sectional view of the spinneret for this fiber drawing process. The four narrow pipes in the figure are the gas pipes to supply nitrogen gas to small holes in the photonic crystal lattice. In the schematic figures, the number of pipes does not correspond to the actual number of holes, and also the pipe for the large central hole is not shown, which is also connected to a nitrogen gas supply.
The viscous polymer solution is fed into the spinneret and the fiber is drawn with a big hole and many small holes. The nitrogen pressures for each of the pipes are controlled separately to tailor the sizes and positions of each of the holes. It is not necessary to provide different pressures to each of the holes. The rotational symmetry allows for the distribution of ...