Liang Youting, Zhou Junxia, Liu Zhaoxiang, Zhang Haisu, Fang Zhiwei, Zhou Yuan, Yin Difeng, Lin Jintian, Yu Jianping, Wu Rongbo, Wang Min, Cheng Ya
State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, China.
The Extreme Optoelectromechanics Laboratory (XXL), School of Physics and Electronic Sciences, East China Normal University, Shanghai 200241, China.
Nanophotonics. 2022 Jan 17;11(5):1033-1040. doi: 10.1515/nanoph-2021-0737. eCollection 2022 Feb.
Erbium doped integrated waveguide amplifier and laser prevail in power consumption, footprint, stability and scalability over the counterparts in bulk materials, underpinning the lightwave communication and large-scale sensing. Subject to the highly confined mode in the micro-to-nanoscale and moderate propagation loss, gain and power scaling in such integrated devices prove to be more challenging compared to their bulk counterparts. In this work, a thin cladding layer of tantalum pentoxide (TaO) is employed in the erbium doped lithium niobate (LN) waveguide amplifier fabricated on the thin film lithium niobate on insulator (LNOI) wafer by the photolithography assisted chemo-mechanical etching (PLACE) technique. Above 20 dB small signal internal net gain is achieved at the signal wavelength around 1532 nm in the 10 cm long LNOI amplifier pumped by the diode laser at ∼980 nm. Experimental characterizations reveal the advantage of TaO cladding in higher optical gain compared with the air-clad amplifier, which is further explained by the theoretical modeling of the LNOI amplifier including the guided mode structures and the steady-state response of erbium ions.
与块状材料中的同类产品相比，掺铒集成波导放大器和激光器在功耗、占地面积、稳定性和可扩展性方面具有优势，为光波通信和大规模传感提供了支撑。由于在微纳尺度下模式高度受限且传播损耗适中，此类集成器件中的增益和功率缩放比其块状同类器件更具挑战性。在这项工作中，通过光刻辅助化学机械蚀刻（PLACE）技术，在绝缘体上薄膜铌酸锂（LNOI）晶圆上制造的掺铒铌酸锂（LN）波导放大器中采用了一层薄的五氧化二钽（TaO）包层。在由波长约为980nm的二极管激光器泵浦的10cm长的LNOI放大器中，在1532nm左右的信号波长处实现了超过20dB的小信号内部净增益。实验表征揭示了TaO包层相对于空气包层放大器在更高光学增益方面的优势，这通过对LNOI放大器的理论建模进一步解释，该建模包括导模结构和铒离子的稳态响应。
