5. Conclusion and outlook

Fiber-optic parametric amplifiers have quite exceptional properties in terms of gain width (> 100 nm to 1550 nm), amplification gain (> 70 dB), amplification quality (0 dB noise figure possible) and the ability to perform frequency conversion. Their operating principle is based on a four-wave phase-tuned mixing process. As a result, the shape of their gain curve depends on the dispersion characteristics of the optical fibers, and they are spectrally wider the lower the dispersion, the more powerful the pump and/or the greater the fiber non-linearity. Their experimental implementation requires particular attention to the pump's spectro-temporal properties, as well as to the quality of the optical fiber used, essentially the regularity of its longitudinal properties. For the time being, these constraints prevent the industrial development of these amplifiers, which remain complex and...