| 摘要 |
A planar waveguide with a glass core and a crystalline cladding. In a specific embodiment, the core is doped preferably with Neodymium, Ytterbium, or Erbium. In the best mode, the core is athermal glass with a refractive index uniformity 10−6 or better and the crystalline cladding has a refractive index lower than that of the core by 10−4 to 10−3 with a refractive index uniformity of 10−4. The cladding has high transparency at pump and lasing wavelengths. The coefficient of thermal expansion of the cladding is close to that of the core. In illustrative embodiments, the cladding is Sapphire and the core is aluminate glass. In an alternative embodiment, the cladding is crystal quartz and the core—is phosphate glass. By utilizing different materials for the core and cladding, the properties of each are optimized. Use of glass for the core allows much more flexibility in tailoring the properties of the core and the PWG geometry readily accommodates the low thermal conductivity of a glass core because the overall thermal performance is dominated by the higher thermal conductivity of the crystalline cladding.
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