This paper describes a cantilever-based photoacoustic spectrometer that is capable of gas detection at ppm levels. The use of optical fiber components enables the first demonstration of modulation frequency divisional multiplexing (MFDM) using tunable diode lasers and the photoacoustic spectrometer. The best-case sensitivity of 3.4 × 10-10 cm-1 W Hz-1/2 (3σ) for measurements using a CO2-containing gas standard are consistent with a previously published value of 1.7 × 10-10 cm-1 W Hz-1/2 (1σ). To the best of our knowledge we have presented the first demonstration of MFDM using a cantilever-based photoacoustic spectrometer. An erbium doped fiber amplifier (EDFA) has been used to amplify simultaneous two distributed feedback tunable diode lasers of closely spaced wavelengths as demonstrated by recording photoacoustic (PA) signals of CO and CO2.© (2007) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.