Enhancement of ultrabroadband Bi NIR emission via fluorination for all wavelength amplification of optical communication

Abstract

AbstractBismuth (Bi)‐doped photonic glasses and fibers with broadband near‐infrared (NIR) photoemission have potential applications in tunable lasers and broadband amplifiers. Yet, when it comes to all wavelength amplification of optical communication, it remains challenging to achieve efficient Bi NIR emission in the technically relevant C‐ and L‐ bands (1530‐1625 nm). Here, we propose a scheme by fluorination triggered enhancement of ultra‐broadband Bi NIR emission in nitrided germanate glasses. Besides, compared to previous research, a unique and efficient Bi‐activated ultra‐wideband NIR emission with new emission bands peaked at ~924 and ~1520 nm under excitation of 450 nm are obtained in nitrided germanate glasses after fluorination. Moreover, the fluorination can modulate the local chemical environment by forcing the conversion of aluminum species from AlO4 to AlO5 and AlO6 and consequently increase the flexibility of the glass network structure, which finally induces the conversion of Bi species and then manipulates the relative emission intensity of different Bi NIR centers. Thus, a flat and tunable emission spectrum covering the entire optical communication band is obtained by optimizing the fluoride amount. We believe this work is helpful to design the Bi‐doped tunable fiber lasers and ultra‐broadband amplifiers for all wavelength amplification of optical communication.