Temperature control for coiled gain fiber in fiber amplifier

A temperature controller for a gain fiber of a fiber amplifier, the temperature controller comprising:

• a heat transfer structure disposed in thermal contact with the gain fiber and being configured to support the gain fiber;
• and
• at least one temperature sink being configured to dissipate heat, at least one first portion of the at least one temperature sink being disposed in first thermal conductivity with at least one first section of the heat transfer structure, at least one second portion of the at least one temperature sink being disposed in second thermal conductivity with at least one second section of the heat transfer structure,
• first and second of the at least one temperature sink, the first and second temperature sinks each having a face disposed in opposing thermal contact with the heat transfer structure,
• wherein the first thermal conductivity conducts the heat from at least one first part of the gain fiber to the at least one temperature sink differently than the second thermal conductivity conducts the heat from at least one second part of the gain fiber,
• wherein the heat transfer structure comprises first and second interfaces each having first and second surfaces, the first surfaces disposed against one another, the first surface of one of the first and second interfaces defining a groove configured to support the gain fiber, the first surface of the other being configured to enclose the gain fiber in the groove, the second surfaces of the first and second interfaces each being disposed in thermal contact with one of the first and second temperature sinks.

A temperature controller for a gain fiber of a fiber amplifier, the temperature controller comprising:

• a heat transfer structure disposed in thermal contact with the gain fiber and being configured to support the gain fiber;
• and
• at least one temperature sink being configured to dissipate heat, at least one first portion of the at least one temperature sink being disposed in first thermal conductivity with at least one first section of the heat transfer structure, at least one second portion of the at least one temperature sink being disposed in second thermal conductivity with at least one second section of the heat transfer structure,
• first and second of the at least one temperature sink, the first and second temperature sinks each having a face disposed in opposing thermal contact with the heat transfer structure,
• wherein the first thermal conductivity conducts the heat from at least one first part of the gain fiber to the at least one temperature sink differently than the second thermal conductivity conducts the heat from at least one second part of the gain fiber,
• wherein the heat transfer structure comprises an encasement having a central passage with the gain fiber disposed therein, the encasement and the gain fiber arranged in a coil, wherein at least one of:
• the encasement comprises extruded material composed of copper, aluminum, or thermally conductive metal;
• the passage of the encasement is filled with fluid to conduct the heat from the gain fiber to the encasement;
• the temperature controller comprises first and second of the at least one temperature sink, the first and second temperature sinks each having a face disposed in opposing thermal contact with the heat transfer structure, wherein the faces define one or more ridges and one or more embossed wells configured to provide the first and second thermal conductivities through different amounts of the thermal contact with the first and second sections of the encasement of the heat transfer structure;
• and
• windings of the coil comprise an insulator material arranged between adjacent ones of the windings.

A temperature controller for a gain fiber of a fiber amplifier, the temperature controller comprising:

• at least one temperature sink being configured to dissipate heat;
• and
• a heat transfer structure disposed in thermal contact with the at least one temperature sink, the heat transfer structure defining a groove in a surface thereof and having a plurality of sections, at least one first of the sections comprising a first material having a first thermal conductivity, at least one second of the sections comprising a second material having a second thermal conductivity different than the first material, the groove configured to support the gain fiber wound on the surface of the heat transfer structure,
• wherein the at least one first section having the first thermal conductivity conducts the heat from at least one first part of the gain fiber to the at least one temperature sink differently than the at least one second section having the second thermal conductivity conducts the heat from at least one second part of the gain fiber.

A method, comprising:

• driving at least one fiber amplifier having a gain fiber disposed along a laser light path of a high-power amplifier system;
• cooling at least one temperature sink disposed in thermal contact with a heat transfer structure supporting the gain fiber;
• transferring first heat from at least one first part of the gain fiber to the at least one temperature sink using at least one first thermal conductivity of at least one first section of the heat transfer structure;
• transferring second heat from at least one second part of the gain fiber to the at least one temperature sink using at least one second thermal conductivity of at least one second section of the heat transfer structure;
• and
• mitigating an onset of Stimulated Brillouin Scattering (SBS) on the laser light path by conducting the first heat with the at least one first thermal conductivity differently than conducting the second heat with the at least one second thermal conductivity,
• wherein transferring the first and second heat using the heat transfer structure comprises using first and second interfaces of the heat transfer structure having the gain fiber supported therebetween, the first interface having a first surface defining a groove configured to support the gain fiber, the second interface having a second surface configured to enclose the gain fiber in the groove;
• and wherein the first and second interfaces each comprise the at least one first and second sections.