Demonstration of Optical Gain at 1535 nm Based on ErIII Complex‐Doped Polymer Waveguides Under Light‐Emitting Diode Excitation

• Published in: Advanced optical materials 2024-07, Vol.12 (20), p.n/a
• Main Authors: He, Yan, Man, Yi, Shi, Xiaowu, Xu, Hui, Lin, Zhuliang, Zhang, Baoping, Yu, Daquan, Huang, Yuyang, Zhang, Dan
• Format: Article
• Language: English
• Subjects: 1535 nm; active polymer waveguide; Chemical synthesis; Energy transfer; ErIII Complex; Excitation; Laser damage; Laser pumping; Light emitting diodes; light‐emitting diode excitation; Near infrared radiation; optical gain; Optical pumping; Polymers; Waveguides
• ISSN: 2195-1071; 2195-1071
• DOI: 10.1002/adom.202400496

A near‐infrared luminescent complex Er(DBTTA)3(DBFDPO) [where DBTTA = dibenzotetrathienoacene; DBFDPO = 4,6‐bis (diphenylphosphoryl) dibenzofuran] is synthesized. Based on the intramolecular energy transfer between organic ligands and Er3+ ions, optical gains at 1535 nm are demonstrated in Er(DBTTA)3(DBFDPO)‐doped polymer waveguides under the excitation of light‐emitting diodes (LEDs) instead of laser pumping. Relative gains of 6.4, 8.2, and 10.6 dB are obtained in 1 cm long waveguides with cross‐sectional dimensions of 6 × 4, 4 × 4, and 2 × 3 µm2 respectively, using the vertical top‐pumping mode of a 365 nm LED with 462 mW. Incorporating an ≈100 nm thick aluminum reflector grown under the lower cladding, enhanced the optical gain to 11.6 dB cm−1 in a waveguide with a cross‐section of 4 × 4 µm2, and an internal gain of ≈7.4 dB cm−1 is achieved. By relying on the intramolecular energy transfer and LED top‐pumping technology, the upconversion luminescence of Er3+ ions and thermal damage to polymer waveguides caused by the high power density of laser pumping can be effectively reduced. The complex Er(DBTTA)3(DBFDPO)‐doped polymer can be spin‐coated on different types of waveguides to compensate for optical losses at 1.5 µm and is expected to have a critical role in planar photonic integration. Relying on the intramolecular energy transfer and ultraviolet LED top‐pumping technology, a relative gain of 11.6 dB cm−1 at near‐infrared 1535 nm wavelength can be achieved in complex Er(DBTTA)3(DBFDPO)‐doped polymer waveguides. The upconversion luminescence of Er3+ ions and thermal damage to the polymer waveguide caused by the high power density of laser pumping can be effectively reduced.