One of the main applications of Photodigm DBR lasers is absorption spectroscopy.  In this application, the laser is tuned by varying either current or temperature to sweep the narrow bandwidth output across an absorption line of a species of interest.  Tunable laser diode absorption spectroscopy (TLDAS) can be used to establish a precise frequency reference when the laser output is locked to an atomic transition.  Because these electronic transitions are sensitive to minute perturbations in their physical environment, these frequency references can be used as the basis for atomic clocks, gyros, magnetometers, and gravimeters. TLDAS can also be used to monitor changes in concentration of absorption species, such as O₂ or I₂. 

Photodigm DBR lasers are precisely tunable by varying either current or temperature.  Tuning coefficients are approximately 0.06 nm/C  (25GHz/ deg C) by temperature or  0.003 nm/mA (1 GHz/mA) by current.  With a linewidth of a MHz or less,  and a side mode suppression of greater than 30 dB, the Photodigm DBR laser is able to effectively probe a variety of atomic and molecular species.