Optical encoders play a crucial role in optical communication applications, and there is a substantial demand for innovative designs that are both ultra-compact and high speed. The proposed structure consists of silicon rods in the air background using a square lattice. Nano-coupling rods are used in combination with a waveguide-shaped tuning fork. The photonic bandgap is being calculated using the plane wave expansion method and finite-difference time-domain method to analyze the performance characteristics of optical encoders, such as transmission spectra, electric field view, contrast ratio, and response time. The proposed encoder operates at 1550 nm, allowing it to carry out encoder operations in which only one input port is active, whereas the others are deactivated. The proposed encoder is designed with a fast response time of 137.2 fs, a high data rate of 7.28 Tbps, and an ultra-compact size of 80.06 μm2.