Optical gain at 1.55 m of Er(TMHD)₃ complex doped polymer waveguides based on the intramolecular energy transfer effect

Based on the intramolecular energy transfer mechanism between organic ligand TMHD (2, 2, 6, 6-tetramethyl-3, 5-heptanedione) and central Er3+ ions, optical gains at 1.55 pm were demonstrated in three structures of polymer waveguides using complex Er(TMHD)(3)-doped polymethylmethacrylate (PMMA) as the active material. With the excitation of two low-power UV light-emitting diodes (LEDs) instead of 980 or 1480 nm lasers, relative gains of 3.5 and 4.1 dB cm(-1) were achieved in a 1-cm-long rectangular waveguide with an active core of Er(TMHD)(3)-doped PMMA polymer. Meanwhile, relative gain of 3.0 dB cm(-1) was obtained in an evanescent-field waveguide with cross-section of 4 x 4 mu m(2) using passive SU-8 polymer as core and a similar to 1-pm-thick Er(TMHD)(3)-doped PMMA as upper cladding. By growing a 100 nm thick aluminum mirror and active lower cladding, the optical gain was doubled to 6.7 dB cm(-1) in evanescent-field waveguides because of the stimulated excitation of Er3+ ions in the upper and lower cladding and the improved absorption efficiency. (c) 2023 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement