Ultra-fast all-optical 8-to-3 encoder utilizing photonic crystal fiber

This work proposes a novel design of an 8-to-3 encoder in a photonic crystal fiber (PCF). It is composed of a buffer and three OR logic gates using circular air holes in a silicon dioxide substrate. We have employed the plane-wave expansion technique to analyze the band structure of the proposed PCF and the beam propagation method to study the transmission efficiency and electromagnetic field distributions. Our findings reveal that the encoder operates well within the main third telecommunication window, which corresponds to 1530–1565 nm. The numerical calculations show that transmissions greater than 70% and less than 0.05% are logics 1 and 0, respectively. The proposed encoder has a maximum delay of 7.5 ps, and its total footprint is about 140 µm × 14 µm × 3 mm. This makes the proposed PCF-based encoder suitable for simple and low-cost fabrication, which may find applications in optical communication devices and integrated circuits.