The loss of one bit of information causes energy dissipation in traditional logic gates at ambient temperature, but when the number of bits is greater, as in high-speed networks, the heat released by them is so great that it impacts performance and shortens component lifetime. Using reversible logic gates, which ideally result in zero energy dissipation, these problems in ordinary Boolean functions can be solved. At 100 Gb/s, an all-optical three-input-output reversible PNOR logic gate is numerically simulated in this article using semiconductor optical amplifiers (SOAs)-based switching units. The quality factor (Q-factor) and the bit error rate (BER) are the metrics against which the performance of reversible PNOR operation is assessed. The results indicate the feasibility of realizing all-optically the PNOR gate at 100 Gb/s since the SOA-based scheme, along with correct logic operation, manages to achieve more than acceptable Q-factor and BER.