Fiber optic connector sub-assemblies and related methods

A fiber optic connector sub-assembly, comprising:

• a ferrule having a front end, a rear end, and a ferrule bore extending between the front and rear ends along a longitudinal axis, wherein the ferrule bore includes a first section extending inwardly from the rear end of the ferrule and having a first width, a second section extending inwardly from the front end of the ferrule and having a second width that is less than the first width, and a transition section located between the first section and the second section;
• and
• a bonding agent disposed in at least a portion of both the transition section and the second section of the ferrule bore;
• wherein:
• the bonding agent occupies at least 90% by volume of the second section of the ferrule bore;
• and
• at least 90% of the bonding agent disposed within the second section of the ferrule bore has been melted and solidified;
• the bonding agent comprises a partially cross-linkable polymer resin having a melting point between about 250° C. and about 350° C.;
• and
• the bonding agent that has been melted and solidified comprises the partially cross-linkable polymer resin in a partially crystalline form.

A fiber optic connector sub-assembly, comprising:

• a ferrule having a front end, a rear end, and a ferrule bore extending between the front and rear ends along a longitudinal axis, wherein the ferrule bore includes a first section extending inwardly from the rear end of the ferrule and having a first width, a second section extending inwardly from the front end of the ferrule and having a second width that is less than the first width, and a transition section located between the first section and the second section;
• and
• a bonding agent disposed in at least a portion of both the transition section and the second section of the ferrule bore;
• wherein:
• the bonding agent occupies at least 90% by volume of the second section of the ferrule bore;
• at least 90% of the bonding agent in the second section of the ferrule bore has been melted and solidified;
• the bonding agent that has not been melted and solidified comprises a powdered material;
• the bonding agent has first and second ends along the longitudinal axis, the first end being located in the first section or the transition section of the ferrule bore, and the second end being located in the transition section or the second section of the ferrule bore;
• and
• the first and second ends of the bonding agent have been melted and solidified.

A method of making a fiber optic connector sub-assembly, comprising:

• (a) providing a ferrule having a front end, a rear end, a ferrule bore extending between the front and rear ends along a longitudinal axis, wherein the ferrule bore includes a first section extending inwardly from the rear end of the ferrule and having a first width, a second section extending inwardly from the front end of the ferrule and having a second width that is less than the first width, and a transition section located between the first section and the second section;
• (b) initially disposing a bonding agent in at least the transition section of the ferrule bore;
• (c) heating at least a portion of the ferrule above a melting temperature of the bonding agent initially disposed in the ferrule bore so that at least some of the bonding agent melts;
• and
• (d) solidifying the bonding agent that has melted in step (c), wherein at least some of the bonding agent that has been melted and solidified is disposed in the second section of the ferrule bore;
• wherein a portion of the bonding agent initially disposed in the ferrule bore in step (b) remains below the melting temperature of the bonding agent during steps (c) and (d) so as to not melt and solidify during steps (c) and (d).