What is the "cut-off wavelength" in fiber optics?

The cut-off wavelength in fiber optics refers specifically to the point at which a fiber optic cable begins to exhibit single-mode behavior. This means that at this wavelength and shorter, the fiber will support only one mode or path for light to propagate, thereby minimizing modal dispersion and allowing for clearer signals over longer distances.

This characteristic is particularly important when designing and implementing systems that require high bandwidth and minimal signal degradation, such as telecommunications and high-speed data transmission. Below this specific wavelength, the fiber may support multiple propagation modes, which can lead to increased dispersion and limits on performance.

Understanding the cut-off wavelength helps in selecting the appropriate type of fiber for a given application, ensuring that the installation will meet the required performance standards for data transmission.