A Taper-Fused Microspherical Laser Source

Abstract

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> We report on the realization of an integrated lasing device consisting of a microsphere optical resonator fused to a tapered optical fiber. A microsphere fabricated from Er : Yb-codoped phosphate glass is heated above its glass transition temperature of 375 <emphasis><formula formulatype="inline"> <tex>$^\circ$</tex></formula></emphasis>C by pumping it at 977 nm with 70 mW via a tapered optical fiber. The onset of thermal stress in the glass at a maximum pumping power results in the sphere melting and fusing to the taper coupler, without inhibition of whispering gallery mode lasing. A taper-fused microsphere laser with <emphasis><formula formulatype="inline"><tex>$\sim$</tex> </formula></emphasis>4.5 <emphasis><formula formulatype="inline"> <tex>$\mu$</tex></formula></emphasis>W of lasing power at 1593 nm is demonstrated. </para>