CO2 sensing using absorption bands near 1570nm is very attractive by taking advantage of the mature fiber-amplifier technology derived from fiber-optic telecom heritage. This necessitates sufficient power scaling in 1.5 micrometer fiber-amplifiers, either in the pulsed-mode, or in the cw-mode for modulation spectroscopy. In this SBIR program we propose the design, optimization, experimental evaluation and prototype development of a high-power, high wall-plug efficiency, 1571 nm fiber-amplifier laser transmitter, compatible with multi-line cw intensity-modulated integrated-path differential absorption spectroscopy, with the size, weight and power (SWaP) optimized for airborne and directly supports and enables space-qualifiable roadmap for Earth Venture (2015) and ASCENDS missions. We leverage innovations in high-power 1.5 micrometer fiber-optic technology and fiber-amplifier architecture, while using high-reliability 1.5 micrometer silica-fiber based passive/active components. Our expectation is that at the end of Phase 2, a TRL-6 level hardware can be developed and delivered for an airborne mission, and which is also compatible with a space-flight maturation roadmap.