Atomic structure modelling and its electronic states analysis of aluminium-related bismuth active centre (BAC-Al) in bismuth-doped optical fibre

Abstract

Bismuth-doped optical fibre (BDF) is a significant potential optical material for optical communication owing to its broad gain spectrum attributed to several bismuth active centres (BACs). In this work, we propose and study a simple model of aluminium-related bismuth active centre (BAC-Al) considering both Al and Bi in a member ring, using first principle methods. We analyse an Al-substituted member-ring with different Bi cases: substituted Bi¹⁺, Bi²⁺ and Bi³⁺ as well as interstitial Bi⁰, BiO, BiOH, and Bi₂O, and found that the interstitial Bi⁰ model produces the energy level diagram similar to that of BAC-Al. In addition, we studied the interstitial Bi⁰ in Al-substituted member-rings with different sizes and shapes. Based on our results, we confirmed that the interstitial Bi⁰ in an Al-substituted six-member-ring produces the best agreement in terms of BAC-Al energy level diagram.