What is the purpose of an optical isolator in fiber optics?

An optical isolator is designed to prevent reflected light from re-entering the fiber source, which is crucial for the stability and performance of optical systems. In fiber optic communications, if light traveling in the forward direction is reflected back toward the source, it can cause interference, degrade signal quality, and potentially damage the laser source. By allowing light to pass in one direction while blocking any light traveling in the reverse direction, optical isolators safeguard the integrity of the signal and the source, ensuring that the system operates efficiently.

The other functions listed do not align with the primary purpose of an optical isolator. Amplifying optical signals pertains to optical amplifiers, while combining multiple signals involves devices such as multiplexers. Increasing signal bandwidth relates to various network design and modulation techniques rather than the specific function of isolation in fiber optic systems. Thus, the isolator serves a critical role in maintaining optimal performance in fiber optic communication networks.