A novel all-optical address decoder (AOAD) using an external-cavity-based single-mode Fabry-Perot laser diode (SMFP-LD) is proposed and demonstrated. The proposed AOAD is the combination of logic gates that are cascaded together to give specific functions of the decoder. The working principles of all logic gates are based on the single- and multi-input injection-locking properties of SMFP-LD. The outputs of the proposed AOAD have contrast ratios of above 27 dB in the spectrum domain, clear waveforms, and clear eyes diagrams with good BER at the data rate of 10 Gb/s. The proposed AOAD has several advantages such as a simple and cascadable structure, low cost, and low bias current (below 19 mA) compared with other optical technologies.