The acetylene (12C2H2) P(9) absorption near 1530 nm was measured by recording the transmission of CW laser after 10 m gain fiber filled with 0.3 mbar acetylene gas. A thermal power meter (Ophir 3A-SH) was used to measure the laser power. The tunable laser diode (ID Photonics GMBH, CoBrite DX1, linewidth <100 kHz, maximum output power ~40 mW) was used as a source after amplification.