In networks with data rates exceeding which specified speed are Fabry-Perot (F-P) lasers deemed insufficient?

Fabry-Perot (F-P) lasers are commonly used in fiber optic communications, particularly at lower data rates. However, as data rates increase, the limitations of F-P lasers become more pronounced due to factors such as modal dispersion, lower modulation bandwidth, and increased sensitivity to temperature variations.

For data rates exceeding 2.5 Gbps, F-P lasers struggle to maintain the necessary performance levels. This is because the spectral width of the F-P laser output can lead to increased bit error rates and reduced link performance when transmitting at higher frequencies.

Beyond this threshold, alternative laser technologies, like Distributed Feedback (DFB) lasers, become more suitable. DFB lasers offer better single-mode operation and higher stability, making them more effective for higher data transmission rates, particularly beyond 2.5 Gbps. Therefore, the specified speed of 2.5 Gbps is crucial since it marks the point at which F-P lasers are generally considered insufficient for reliable high-speed data communication.