Plastic optical fiber preform, and process and apparatus for producing the same

A preform for plastic optical fiber, comprising:

• a core comprising an organic polymer;
• a cladding layer comprising an organic polymer and disposed on the outer circumference of the core;
• and
• a jacket layer disposed on the outer circumference of the cladding layer;
• wherein a refractive index modifier b having a refractive index higher than the polymer of the core is optionally added to the core, and a refractive index modifier c having a refractive index lower than the organic polymer of the cladding is optionally added to the cladding layer so that the refractive index of the preform gradually decreases from the center outward, and the core has a higher refractive index than the cladding layer;
• and
• wherein the jacket layer further comprises a functional material.

A preform for plastic optical fiber, comprising:

• a core comprising an organic polymer;
• a cladding layer comprising an organic polymer and disposed on the outer circumference of the core;
• and
• a jacket layer disposed on the outer circumference of the cladding layer;
• wherein a refractive index modifier b having a refractive index higher than the polymer of the core is optionally added to the core, and a refractive index modifier c having a refractive index lower than the organic polymer of the cladding is optionally added to the cladding layer so that the refractive index of the preform gradually decreases from the center outward, and the core has a higher refractive index than the cladding layer;
• and
• wherein the jacket layer further comprises a light absorbing agent.

A preform for plastic optical fiber, comprising:

• a core comprising an organic polymer;
• a cladding layer comprising an organic polymer and disposed on the outer circumference of the core;
• and
• a jacket layer disposed on the outer circumference of the cladding layer;
• wherein a refractive index modifier b having a refractive index higher than the polymer of the core is optionally added to the core, and a refractive index modifier c having a refractive index lower than the organic polymer of the cladding is optionally added to the cladding layer so that the refractive index of the preform gradually decreases from the center outward, and the core has a higher refractive index than the cladding layer;
• and
• wherein the jacket layer further comprises TiO.sub.2 as light scattering agent.

A preform for plastic optical fiber, comprising:

• a core comprising an organic polymer;
• a cladding layer comprising an organic polymer and disposed on the outer circumference of the core;
• and
• a jacket layer disposed on the outer circumference of the cladding layer;
• wherein a refractive index modifier b having a refractive index higher than the polymer of the core is optionally added to the core, and a refractive index modifier c having a refractive index lower than the organic polymer of the cladding is optionally added to the cladding layer so that the refractive index of the preform gradually decreases from the center outward, and the core has a higher refractive index than the cladding layer;
• and
• wherein the organic polymer of the cladding layer is polymethyl methacrylate and the refractive index modifier c is selected from the group consisting of hexyl acetate, bis(3,5,5-methylhexyl) phthalate and bis(2-methylhexyl)phthalate.

A preform for plastic optical fiber comprising:

• a core comprising a first organic polymer;
• a cladding layer comprising a second organic polymer and disposed on the outer circumference of said core;
• and
• a jacket layer comprising a third organic polymer and disposed on the outer circumference of said cladding layer;
• wherein said third organic polymer comprises at least 90 mol % of the same monomer or monomers as contained in said second organic polymer and has a melting point substantially the same as that of the first organic polymer;
• and
• wherein a refractive index modifier b having a refractive index higher than the first organic polymer is optionally added to the core so that the refractive index of the preform gradually decreases from the center outward, and the core has a higher refractive index than the cladding layer.