Effect of noise-induced wavelength fluctuation in tunable diode lasers on narrow-linewidth absorption measurements.

Tunable diode laser absorption spectroscopy is being widely used to make sensors for diagnostic purposes in various engineering applications. Since the wavelength of many diode lasers used in such sensors is sensitive to the driving current, even noise as small as a few μA in the driving current can cause a wavelength fluctuation of ∼±0.5  pm, which is large enough to interfere with sensitive absorption measurements.