basic background area: With the advent of the information age and the increasing demand for high bandwidth and high speed data transmission, fiber optic communication has become the main means of transmitting large amounts of data, especially in long distance communication and high speed internet applications. Especially in LIDAR (Light Detection and Ranging System), optical receivers are used to detect the reflected back light signals and thus calculate the information such as distance, shape and speed etc. LIDAR is widely used in autonomous driving, UAV navigation and robot vision, which requires optical receivers with high sensitivity, fast response and high dynamic range performance. With the development of technologies such as 5G, Internet of Things (IoT), and satellite Internet, the need for high-performance optical receivers is becoming more pressing. These technologies require receivers to be miniaturized, intelligent, and able to operate at lower power consumption for portable and embedded applications, and these optical receivers, not only require devices that can operate under low light intensity conditions, but also require good anti-interference capabilities in complex environments. 

Aims and Objectives:

Underwater communications can encounter significant difficulties such as increased signal attenuation, reduced penetration, massive absorption and significant interference. Penetration, massive absorption and significant interference, all of which lead to degradation of signal quality. Together, these problems shrink the communication range and complicate the system architecture, thus degrading the performance of RF technology. So, in this research , i would like to study an optical receiver for the reason that optical communication for underwater applications can provide more advantages such as high bandwidth, low attenuation small, less interference, better directionality, more security, and resistance to electromagnetic interference. Firstly, by reading through the various texts, I wanted to first find the most suitable optical communication for underwater use by using LEDs with different wavelengths of the same light color; then I also needed to find a suitable photodetector and compare the responsiveness, bandwidth, noise, and so on in order to support me in designing a better quality optical receiver. In addition to this, with the development of technology nowadays, is it possible to add artificial intelligence to the receiver, so that it can be measured autonomously at any time, so that the optical receiver is always in the best operating condition. Signal amplifier and filter design, I need to convert the detected photoelectric signals into electrical signals, in this process I need filters to eliminate the noise. Of course, in optical communication, receivers are generally required to demodulate the received signals, so it is also necessary to study how to improve the performance of optical receivers by optimizing the demodulation technique, including improving the anti-interference ability and reducing the bit error rate. 

The goal of this BEng project is to design and optimize a high-performance optical receiver that can meet the needs of application scenarios such as optical communication, sensing and detection. Through experiments and theoretical analysis, we investigate how to improve the sensitivity, bandwidth and anti-interference ability of the optical receiver. Optical receivers are made to perform better in signal conversion and processing by exploring new materials, structures and algorithms.