In this paper, we apply photonic data rate reduction based on SOA-loop memories to Deep Packet Inspection (DPI) without the need for high speed opto-electronic conversions. The architecture presented makes use of fast optical subsystems based on Semiconductor Optical Amplifiers, and aided by low cost slow rate electronics; the desired header fields are extracted and their signal rate is slowed down in the optical domain before delivering the selected information to the electronic processing for DPI operations.