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.

We theoretically investigated the effect of the spatial distribution of the active-ion concentration in multimode step-index waveguides on transverse-mode selection for continuous-wave laser operation. We found that uniform doping of a central portion of as much as 60% of the full waveguide core width is highly effective for the selection of fundamental-mode operation, even under highly saturated, high-power conditions. Profiling the dopant distribution to match that of the particular mode desired was also found to be effective, especially if it is the saturated inversion profile that is matched to the shape of the mode.

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Abstract-We report the first fabrication and laser operation of channel waveguides based on LaF 3 planar thin films grown by molecular beam epitaxy. To our knowledge, this is the lowest phonon energy dielectric material to have shown guided-wave laser operation to date. A full characterization, in terms of spectroscopy, laser results, and propagation losses, is given for the planar thin films upon which the channel waveguides are based. Two channel-fabrication methods are then described, the first involves ion milling and the second takes the novel approach of using a photo-definable polymer overlay. Laser operation in Nd-doped samples is demonstrated at 1.06, 1.05, and 1.3 m, and the potential for mid-infrared laser sources based on such guides is discussed.

We demonstrate the suitability of a simple continuous-wave-pumped transition-metal-ion-doped waveguide as a broadband light source in the wavelength region 600-1000 nm for interferometric applications. Spatially coherent (single mode in the confined direction), spectrally broadband (~130-nm FWHM) luminescence with output powers of several hundreds of microwatts is obtained from a Ti:sapphire planar waveguide with incident pump powers from an Ar-ion laser of up to 1 W. This result represents an increase in power by several orders of magnitude from previously reported simple broadband light sources in this wavelength range.