The uniqueness of glass for passive thermal management for optical fibers

Optical fiber‐based lasers and amplifiers are ubiquitous tools across many practical applications including communications, metrology, sensing, manufacturing, machining, and directed energy. Even for the most efficient cases where only a few percent of the optical power is converted into heat, this heat generation can have wide‐ranging detrimental effects on overall system performance. In homage to the 2022 International Year of Glass, this paper provides a new look into the enabling roles that glass can play in the fully passive thermal management of active fiber lasers and amplifiers. Partially didactic, complemented with new insights and novel approaches and results, specific topics include means by which glass compositions can reduce the amount of heat generated by an active dopant and how the glass’ response to heat generation, for example, thermo‐optic and thermal expansion coefficients, can be minimized or otherwise used to largely mitigate parasitic thermal effects.