**Luigi Sirleto \* and Maria Antonietta Ferrara**

National Research Council (CNR), Institute of Applied Sciences and Intelligent Systems, Via Pietro Castellino 111, 80131 Naples, Italy; antonella.ferrara@na.imm.cnr.it

**\*** Correspondence: luigi.sirleto@cnr.it

Received: 10 January 2020; Accepted: 24 February 2020; Published: 26 February 2020

**Abstract:** Nowadays, in fiber optic communications the growing demand in terms of transmission capacity has been fulfilling the entire spectral band of the erbium-doped fiber amplifiers (EDFAs). This dramatic increase in bandwidth rules out the use of EDFAs, leaving fiber Raman amplifiers (FRAs) as the key devices for future amplification requirements. On the other hand, in the field of high-power fiber lasers, a very attractive option is provided by fiber Raman lasers (FRLs), due to their high output power, high efficiency and broad gain bandwidth, covering almost the entire near-infrared region. This paper reviews the challenges, achievements and perspectives of both fiber Raman amplifier and fiber Raman laser. They are enabling technologies for implementation of high-capacity optical communication systems and for the realization of high power fiber lasers, respectively.

**Keywords:** stimulated raman scattering; fiber optics; amplifiers; lasers; optical communication systems
