Optical properties of bismuth-doped silica fibres in the temperature range 300 — 1500 K

Effects of Post Treatments on Bismuth-Doped and Bismuth/ Erbium Co-doped Optical Fibres

“…100°C/200°C/ in air [37] Note: PIT-powder in tube, SPCVD-surface plasma chemical vapour deposition, FCVD-furnace chemical vapour deposition, MCVD-modified chemical vapour deposition. Similar effects have been observed when ASBiY [34] is annealed at ≥550°C and ASBi at 1200°C [35] as listed in Table 1. After annealing, absorption peaks of BAC-Al at 500, 750 and 1000 nm increase, and the NIR emission at 1150 nm is enhanced.…”

“…It is observed that the emission of BAC-Si at ~1420 nm shows an increasing trend when treating at a specific high temperature, along with the reduction of emission at 830 nm. It is believed that the increase of NIR emission is associated with the increase of the non-radiative transition rate between ES 2 and ES 1 of BAC-Si (Figure 1) at high temperature, which is confirmed by the lifetime results in GSBi [31] and SBi* [33]. Taking GSBi [31] for example, the lifetime at ES 2 of BAC-Si drops directly from 30 μs to <3 μs, whereas the lifetime of 1400nm luminescence decreases by 25% when heating from room temperature to 900°C, as shown in Figure 2.…”

“…In addition, the reduction of emission of BAC-Si has also been observed in SBi-H, SBi-HF and GSBi after annealing at high temperature, as listed in Table 1 [31,32]. The features, behaviours and causes of these phenomena vary case by case.…”

“…Another possibility is the reconfiguration of clusters in a greater porosity in SBi-HF [32], resulting in an irreversible reduction of their luminescence. In addition, the dissociation of BAC-Si due to the oxidation by GeO 2 is also observed in GSBi [31], although it is a reversible process.…”

“…However, their interpretations are not convincible owing to the limited data. Later on, thermal effects on emission of BAC-Si at 830 nm and 1420 nm under 808 nm pumping have been studied in bismuth-doped silicate fibres (SBi) [31,32], bismuth-doped germanosilicate fibre (GSBi) [31] as well as bismuth-doped silicate tube (SBi*) [33] (Table 1). It is observed that the emission of BAC-Si at ~1420 nm shows an increasing trend when treating at a specific high temperature, along with the reduction of emission at 830 nm.…”