High power broadband superluminescent diode for compact gas sensor

Tunable mid-infrared semiconductor light sources are of particular interest for molecular spectroscopy; for example, CO2 and other atmospheric gases have strong absorption lines in this wavelength range. Currently, to detect multiple gases simultaneously one needs several continuous-wave (CW) operated mid-infrared laser diodes (LDs) with wide tuning range. For a miniaturized gas sensing system, a single high power and broadband light source is desired. To this end, we have proposed a novel, programmable/tunable light source for gas detection utilizing broadband superluminescent diode (SLD) and Si-based photonic integrated components [1]. When it comes to light source development, the preferred material system for reaching the 2-3 μm wavelength range is GaSb. Even though the performance of GaSb-based devices [2] are superior to InP-based emitters [3] in this wavelength range, the development of GaSb-based SLD have not been notable until recently [4].