What is the main factor in determining the sensitivity of an optical receiver?

The sensitivity of an optical receiver primarily hinges on noise levels. Sensitivity refers to the minimum amount of optical signal power required for the receiver to adequately distinguish the signal from the noise present within the system. Noise can stem from various sources, including electronic fluctuations within the receiver and external interferences affecting the optical signal.

An optical receiver requires a clear distinction between the transmitted signal and the background noise to effectively recover the information being sent. High levels of noise can obscure the signal, leading to errors in data transmission and ultimately affecting the reliability of the communication system. By optimizing for lower noise levels, a receiver can achieve higher sensitivity, enabling it to accurately receive weaker signals.

While signal strength, wavelength, and temperature can influence the overall performance of an optical system, they do not directly define sensitivity in the way that noise does. Signal strength is important but only in the context of how it compares to noise. Wavelength can impact the design of the receiver and its efficiency, and temperature can affect the receiver's performance characteristics, yet noise remains the primary determinant of sensitivity in practical optical communication.