Spectroscopy and 400 nm-induced photodarkening measurements in Sm3+-doped aluminophosphosilcate fibre

• Published in: Optical materials express Vol. 14; no. 9; p. 2148
• Main Authors: Ososkov, Yan, Lee, Jinho, Jackson, Stuart D
• Format: Journal Article
• Language: English
• Published: Washington Optical Society of America 01.09.2024
• Subjects: Absorption; Color centers; Fiber lasers; Glass fibers; Parameters; Photodarkening; Photoionization; Samarium; Semiconductor lasers; Spectroscopic analysis
• ISSN: 2159-3930
• DOI: 10.1364/OME.534751

We present initial measurements of the basic spectroscopic parameters and photodarkening characteristics for a Sm3+-doped aluminophosphosilicate (APS) glass fibre with a large phosphorous-to-aluminium ratio that is pumped at 400 nm using an InGaN diode laser. The spectroscopic parameters are compared with previous studies. We demonstrate that the presence of a P:Al ratio ∼9 leads to the formation of P-related colour centres only, causing absorption in the visible part of the spectrum that directly overlaps with the strongest Sm3+ transitions at 600 nm and 650 nm. We propose an explanation for the photoionization of the P-related defect precursors in high P:Al ratio APS glass based on excited state absorption from the upper state of Sm3+ that is followed by subsequent high-energy UV photons emission. We also establish that large P:Al ratios in APS fiber can effectively inhibit the reduction of Sm3+ to Sm2+. These findings lay the groundwork for further development of visible fibre lasers based on Sm3+-doped silicate glass.