Optical fiber with reducing hydrogen sensitivity

A method of producing an optical fiber comprising:

• providing a preform having a consolidated glass core and a first porous glass cladding layer;
• exposing the preform to a first gas atmosphere at a first temperature, the first gas atmosphere comprising a chlorine source material, the chlorine source material providing chlorine for doping the first porous glass cladding layer;
• exposing the preform to a second gas atmosphere at a second temperature;
• the second gas atmosphere comprising a reducing agent;
• and
• heating the preform in the presence of the second gas atmosphere at a third temperature;
• the heating causing sintering of the first porous glass cladding layer, the sintered first porous glass cladding layer having a chlorine dopant concentration of at least 500 ppm by weight;
• wherein the reducing agent is CO and the concentration of CO in the second gas atmosphere is greater than 1000 ppm by volume.

A method of producing an optical fiber comprising:

• providing a preform having a consolidated glass core and a first porous glass cladding layer;
• exposing the preform to a first gas atmosphere at a first temperature, the first gas atmosphere comprising a chlorine source material, the chlorine source material providing chlorine for doping the first porous glass cladding layer;
• exposing the preform to a second gas atmosphere at a second temperature;
• the second gas atmosphere comprising a reducing agent;
• and
• heating the preform in the presence of the second gas atmosphere at a third temperature;
• the heating causing sintering of the first porous glass cladding layer, the sintered first porous glass cladding layer having a chlorine dopant concentration of at least 500 ppm by weight;
• wherein the second gas atmosphere comprises the first gas atmosphere and
• wherein the volumetric ratio of the reducing agent to the chlorine source material in the second gas atmosphere is greater than 0.005.

A method of producing an optical fiber comprising:

• providing a preform having a consolidated glass core and a first porous glass cladding layer;
• exposing the preform to a first gas atmosphere at a first temperature, the first gas atmosphere comprising a chlorine source material, the chlorine source material providing chlorine for doping the first porous glass cladding layer;
• exposing the preform to a second gas atmosphere at a second temperature;
• the second gas atmosphere comprising a reducing agent;
• and
• heating the preform in the presence of the second gas atmosphere at a third temperature;
• the heating causing sintering of the first porous glass cladding layer, the sintered first porous glass cladding layer having a chlorine dopant concentration of at least 500 ppm by weight;
• wherein the reducing agent is CO and the ratio of the concentration of CO in the second gas atmosphere in units of ppm by volume to the chlorine dopant concentration in the sintered first porous glass cladding layer in units of ppm by weight is greater than 0.5.

A method of producing an optical fiber comprising:

• providing a preform having a consolidated glass core and a first porous glass cladding layer;
• exposing the preform to a first gas atmosphere at a first temperature, the first gas atmosphere comprising a chlorine source material, the chlorine source material providing chlorine for doping the first porous glass cladding layer;
• exposing the preform to a second gas atmosphere at a second temperature;
• the second gas atmosphere comprising a reducing agent;
• and
• heating the preform in the presence of the second gas atmosphere at a third temperature;
• the of the first glass cladding layer, the sintered first porous glass cladding layer having a chlorine dopant concentration of at least 500 ppm by weight;
• wherein the chlorine dopant concentration in the sintered first porous glass cladding layer is greater than 2000 ppm by weight.

A method of producing an optical fiber comprising:

• providing a preform having a consolidated glass core and a first porous glass cladding layer;
• exposing the preform to a first gas atmosphere at a first temperature, the first gas atmosphere comprising a chlorine source material, the chlorine source material providing chlorine for doping the first porous glass cladding layer;
• exposing the preform to a second gas atmosphere at a second temperature;
• the second gas atmosphere comprising a reducing agent;
• and
• heating the preform in the presence of the second gas atmosphere at a third temperature;
• the heating causing sintering of the first porous glass cladding layer, the sintered first porous glass cladding layer having a chlorine dopant concentration of at least 500 ppm by weight;
• wherein the preform further comprises a second porous glass cladding layer, the second porous glass cladding layer surrounding the first porous glass cladding layer.