HFC Designer I & II Certification Practice Exam

The drawback of using Fabry-Perot (F-P) lasers in high-speed data networks primarily relates to their emission of multiple discrete wavelengths. This characteristic can cause issues with signal interference and bandwidth efficiency. F-P lasers are designed with a cavity that can support multiple longitudinal modes; this results in the emission of light at several wavelengths rather than a single wavelength. Consequently, when used in data networks that require high precision and clear signal differentiation, the presence of these multiple discrete wavelengths can lead to increased modal dispersion and potential degradation of the signal quality. This can ultimately limit the effectiveness of the network when trying to achieve high data rates, as it complicates signal processing and may lead to reduced system performance.

In contrast, the considerations regarding cost, signal-to-noise ratio, and temperature sensitivity are indeed relevant to laser performance, but they may not impact the operation and efficiency of data transmission as significantly as the issue of multiple wavelengths emitted by F-P lasers.