The lasing wavelength shift characteristics of amplified spontaneous emission (ASE)-injected wavelength-locked Fabry-Perot laser-diodes used in the wavelength division multiplexed passive optical network are studied. The lasing wavelength shift at different injected-ASE powers and different bias currents are experimentally evaluated. The saturation effect has been found as the bias current increases. (C) 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53: 1522-1524, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26088