Frequency stabilization of 1.5-μm InGaAsP distributed feedback laser to NH3 absorption lines

Abstract

NH3 absorption lines due to vibration-rotation transitions are observed at 1.50–1.54 μm by using an InGaAsP superluminescent diode. A 1.5-μm InGaAsP distributed feedback (DFB) laser is frequency stabilized to an NH3 linear absorption line at 15196 Å. Frequency stability of σ(2,τ)=8×10−11τ−1 is achieved for an averaging time range of 10 ms≤τ≤1 s. Such an absolute frequency-stabilized DFB laser is useful for coherent optical system applications, since it is free from the longitudinal mode jumping which results from a wide range of temperature changes and long-term device degradation.