Double-clad structures and proximity coupling for diode-bar-pumped planar waveguide lasers

Abstract

Abstract-We report, for the first time, fabrication of double-clad planar waveguide structures and their use for multiwatt, diode-bar-pumped, planar waveguide lasers based on Nd 3+ -and Yb 3+ -doped YAG. The direct-bonded, five-layer structures of sapphire, YAG, and rare-earth-doped YAG have sufficient numerical aperture to capture the fast-axis divergence of a diode bar by proximity coupling with no intervening optics, leading to very simple and compact devices. The restriction of the doped region to the central core leads to diffraction-limited laser output in the guided direction. We also show that the direct-bonding fabrication process can lead to a linearly polarized output.

Modeling of high-power continuous-wave Tm:YAG side-pumped double-clad waveguide lasers

“…The fitted one-way transmission corresponds to a propagation loss coefficient at 2.02 m of 0.04 dB/cm. This is somewhat lower than the values found at 1 m for similar Nd-and Yb-doped double-clad waveguides [10], [11] (0.2 dB/cm) and is approaching reported values at 1 m for bulk Nd:YAG rods [12] (0.03 dB/cm). The excellent fit to the experimental results using reasonable parameter values allows predictions to be made for optimization and power scaling of this system with some confidence.…”

“…The output characteristic of this waveguide has important implications for which method could be used to control the spatial properties of the laser in the nonguided plane. Typically, the combination of side-pumping with the plane/plane laser resonator used here leads to highly multi-mode output in the non-guided plane [5], [10], [15]. It has been proposed [16] that monolithic hybrid-guided/unstable resonators would be a potential solution to this problem because of the high gains available from diode-pumped waveguide lasers.…”

Low phonon energy, Nd:LaF/sub 3/ channel waveguide lasers fabricated by molecular beam epitaxy

“…Planar devices are geometrically well suited to highpower diode pumping [6] and also hold the potential for the production of on-chip integrated devices. However, demonstrations of laser action in fluoride dielectric planar geometries have so far been quite limited, with only recent reports of near-IR ( 1.06 m) lasing in Nd : YLF grown by liquid-phase-epitaxy [7] and Nd-doped fluoroaluminate glass by spin-coating [8].…”

Growth of a multilayer garnet crystal double-clad waveguide structure by pulsed laser deposition

“…Directbonding has been used to create advanced multilayer structures on sapphire substrates with Nd:YAG cores and YAG inner cladding layers capped with a sapphire layer [4].…”