The development of coherent sources and other optical components for the mid-infrared has been hampered by the lack of sturdy materials that can withstand high power radiation or exposition to harsh environment. BGG glasses are robust materials transmitting over the 2.5–5 μm region. We report here the direct femtosecond laser fabrication of efficient directional couplers integrated in a BGG glass chip. The photonic components are characterized from 2.1 to 4.2 μm and compared to similar structures inscribed in silica glass samples. At 2.85 μm, a 99% relative cross transmission is reported in BGG glass. The experimental measurements are in good agreement with the coupled mode theory for wavelengths up to 3.5 μm.

中文翻译：

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在BGG玻璃中直接激光写入的集成中红外定向耦合器

由于缺乏能够承受高功率辐射或暴露于恶劣环境的坚固材料，阻碍了中红外相干光源和其他光学组件的开发。BGG眼镜是发送在2.5-5鲁棒材料μ米区域。我们在此报告集成在BGG玻璃芯片中的高效定向耦合器的直接飞秒激光制造。光子组件从2.1表征以4.2 μ m和相比二氧化硅玻璃样品中内接的类似结构。在2.85 μ M，A 99％的相对横传输中报道了BGG玻璃。实验测量是在与耦合模理论一致为波长可达3.5 μ米。