Low-Cost Fiber-Based Dual-Comb Spectrometer for Near-Infrared Molecular Spectroscopy

Two erbium-fiber-based 100 MHz optical frequency combs centered at 1550 nm of two different designs have been constructed and stabilized by undergraduate students at a small liberal-arts college using a combination of low-cost and home-built instrumentation. Designs for their construction and stabilization are presented, as well as their spectra and performance details. Electronic stabilization is inexpensively achieved using an Arduino Uno for temperature control, and Red Pitaya FPGAs to control a pair of intracavity piezoelectric transducers and the pump current of each oscillator. The fully stabilized system of both combs is suitable for near-infrared dual-comb spectroscopy, and costs roughly $30,000 in equipment and parts — a fraction of the price of a comparable commercial system — demonstrating the feasibility of building a comparable system in other financially constrained laboratories.