Patent ID: 9586853
Date: 2017-03-07
CPC Classifications: C03B,G02B,Y02P

Claim:
1. A method of producing an optical fiber comprising: providing a porous soot cladding monolith, said soot cladding monolith including a first porous glass cladding layer and having an internal cavity; inserting a core cane into said internal cavity to form a core-cladding assembly, said core-cladding assembly including a channel between said core cane and said soot cladding monolith; exposing said core-cladding assembly to a first gas atmosphere at a first temperature, said first gas atmosphere comprising a chlorine source material, said chlorine source material providing chlorine for doping said first porous glass cladding layer; exposing said core-cladding assembly to a second gas atmosphere at a second temperature, said second gas atmosphere comprising a reducing agent, said reducing agent being CO and having a concentration in said second gas atmosphere greater than 3000 ppm by volume; and heating said core-cladding assembly in the presence of said second gas atmosphere at a third temperature, said heating causing sintering of said first porous glass cladding layer, said sintered first porous glass cladding layer having a chlorine dopant concentration of at least 500 ppm by weight.