A tapered fiber bundle device couples optical power from an optical power source into an output fiber. The tapered fiber bundle device includes a tapered fiber bundle including a set of bundled fibers having a near end and a distal end. The near end of the tapered fiber bundle is configured to collect the optical power from the optical power source. Each fiber k in the set of bundled fibers has a first cross-sectional area Ak(1) at the near end and a second cross-sectional area Ak(2) at the distal end such that Ak(2) is substantially smaller than Ak(1). Each fiber also has a substantially uniform core and a substantially uniform numerical aperture value NAin. A cross-sectional area of the set of bundled fibers at the distal end has a cross-sectional area value Adist substantially equal to Aout.