Reflective semiconductor optical amplifier (RSOA) is an efficient gain medium and finds application in passive optical network. Due to its double-pass characteristics compared to ordinary semiconductor optical amplifier, gives better switching performance. RSOA based gain dynamics is utilized to design and analyze the NOR gate using soliton pulses for the first time in this communication. The simulation results using MATLAB show an efficient performance (Q value more than 80 dB) of this gate with less complexity in hardware. The NOR gate is characterized by calculating extinction ratio (ER ~ 14 dB), contrast ratio (CR ~ 15 dB), Q value (~ 90 dB), and the effect of amplified spontaneous emission noise is also investigated. This NOR gate uses a single RSOA and can be used to design any optical logic processors in future.