Bismuth　(Bi)-doped　glasses　and　fibers　are　the　most　promising　gain　media　to　solve　the　capacity　crisis　in　optical　communication　systems　due　to　their　broadband　near-infrared　luminescence　covering　O-U　bands.　To　date,　only　Bi-doped　fibers　prepared　by　the　modified　chemical　vapor　deposition　method　have　been　well-developed,　providing　net　gain　performance.　However,　the　crucial　technological　challenges　have　not　been　fully　resolved,　such　as　the　high　fabrication　cost　and　the　balance　among　unsaturated　loss,　doping　concentration,　and　unit　gain.　In　this　work,　we　propose　a　modified　sol–gel　method　for　low　temperature　synthesis　of　highly　homogeneous　Bi-doped　glasses.　By　using　HF　and　HCl　as　the　coordinated　catalysis,　a　series　of　uniform　Bi-doped　glasses　with　low　OH−　content　(∼4.5　ppm)　was　prepared　at　1300　°C　within　3.5　days.　The　Bi-doped　glasses　present　broadband　luminescence　covering　the　O-U　band,　attributed　to　the　superposition　of　multiple　bismuth　active　centers　(BACs),　and　provide　relatively　high　fluorescence　lifetimes　(657–735　μs).　On　this　basis,　Bi-doped　GeO2-SiO2　fibers　(BGSFs)　were　prepared　via　the　rod-in-tube　method.　Utilizing　a　40　m　BGSF　as　the　gain　media,　an　amplifier　was　constructed　using　backward　pumping.　As　the　pump　power　of　808　nm　laser　diode　reached　100　mW,　positive　gain　was　obtained　in　the　range　of　1200–1600　nm　with　a　maximum　on-off　gain　of　0.9　dB/m　at　1395　nm.　These　results　suggest　that　our　modified　sol–gel　method　holds　promising　potential　for　flexible　fabrication　of　Bi-doped　glasses　and　fibers.　©　2024　Elsevier　Ltd　and　Techna　Group　S.r.l.