Design and Experimental Analysis of a Laser-Based Li-Fi Communication System

Light Fidelity (Li-Fi) is an emerging optical wireless communication (owc) system that employ light-emitting diodes (LEDs) to acheive medium to high speed transmission using optical signals. Li Fi is a form of Visible light communication(VLC) technology i.e. lifi provides secure communication connectivity for under water communication,smart home, smart cities, classrooms and hospital,medicial equipment,traffic and vehicle communication. It strengthens security compared to modern radio-frequency (RF) communication systems. RF-based systems are sensitive to jamming, and the available spectrum is heavily occupied due to multiple devices operating on the same frequency band. This results in issues such as low data quality, collisions, and interference, particularly in indoor environments.In this work, a low-cost Li-Fi communication system is implemented to address these limitations while keeping the system affordable and simple. The proposed approach uses microcontrollers such as ESP8266 and ESP32 as the transmitter and receiver, respectively. At the transmitter side, text data are entered from a phone or laptop into the ESP8266 through a serial interface and transmitted using a laser diode.The laser diode is controlled via On-Off Keying (OOK) modulation, in which the light source alternates between ON and OFF states to represent binary data. By streamlining the encoding and decoding process, this method facilitates the receiver’s detection and interpretation of the transmitted text. At the receiver side, an ESP32 microcontroller is used to handle the received data, process it, and display the decoded text on an OLED screen. A high-sensitivity light dependent resistor (LDR) sensor module is used to sense the incoming light signal in real time, and threshold-based detection is applied to distinguish between logic levels. The system was tested indoors under normal lighting conditions, and successful text transmission was observed without noticeable interference during communication. The experimental result of Li-Fi demonstrate the high speed data transmission upto 100 Gbps.