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Fully-monolithic single-active fiber difference frequency generation source for simultaneous multi-species gas sensing

Laser spectroscopy based trace gas detection systems are implemented in various applications: industry, medicine, homeland security, environmental monitoring and several more [1]. More sophisticated applications require simultaneous monitoring of several gas species, that possess strong absorption lines in the mid-IR wavelength region. This usually requires using several independent laser sources that will enable targeting the desired transitions of the analytes — for example relatively expensive quantum cascade lasers [2]. We propose a novel, multi-wavelength, fully-monolithic, fiber-based difference frequency generation mid-IR source, incorporating our patented dual-wavelength double-clad (DC) configuration, which enables amplification of ∼1.55 μm radiation and simultaneous generation of 1.064 μm wavelength [3-5]. Schematic is shown in Fig. 1.