Advanced distributed feedback lasers based on composite fiber heavily doped with erbium ions

• Published in: Scientific reports 2020-09, Vol.10 (1), p.14487-14487, Article 14487
• Main Authors: Skvortsov, Mikhail I., Wolf, Alexey A., Vlasov, Alexander A., Proskurina, Kseniya V., Dostovalov, Alexander V., Egorova, Olga N., Galagan, Boris I., Sverchkov, Sergey E., Denker, Boris I., Semjonov, Sergey L., Babin, Sergey A.
• Format: Article
• Language: English
• Subjects: 639/624/1020/1086; 639/624/1075/1080; 639/624/1075/187; Apolipoprotein E; Cerebellum; Cognitive ability; Diagnosis; Frontal gyrus; Functional magnetic resonance imaging; Genotype & phenotype; Humanities and Social Sciences; multidisciplinary; Neural networks; Science; Science (multidisciplinary); Temporal gyrus
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-020-71432-w

Specially designed composite heavily Er 3+ -doped fiber in combination with unique point-by-point inscription technology by femtosecond pulses at 1,026 nm enables formation of distributed-feedback (DFB) laser with ultra-short cavity length of 5.3 mm whose parameters are comparable and even better than those for conventional Er 3+ -doped fiber DFB lasers having much longer cavity. The composite fiber was fabricated by melting rare-earth doped phosphate glass in silica tube. The ultra-short DFB laser generates single-polarization single-frequency radiation at 1,550 nm with narrow linewidth (3.5 kHz) and 0.5 mW output power at 600 mW 980-nm pumping. The same fiber with conventional CW UV (244 nm) inscription technology using phase mask enables fabrication of 40-mm long DFB laser with > 18 mW output power at 3.3% pump conversion, which is a record efficiency for Er 3+ -doped fiber DFB lasers. The developed technologies form an advanced platform for Er 3+ -doped fiber DFB lasers operating around 1.55 µm with excellent output characteristics and unique practical features, in particular, the ultra-short DFB lasers are attractive for sensing applications.