Ding Yuedi, Tao Shiqi, Wang Xuanhao, Shang Chenglin, Pan An, Zeng Cheng, Xia Jinsong
Opt Express. 2022 Jun 6;30(12):22135-22142. doi: 10.1364/OE.458218.
Lithium niobate on insulator (LNOI) is a new photonic integrated platform that provides high optical confinement and retains the inherent excellent properties of lithium niobate (LN). Tunable filters are one of the indispensable devices for integrated optics. Here we design and fabricate a thermo-optic (TO) tunable optical filter using two cascaded racetrack microring resonators (MRRs) based on LNOI. The filter shows a narrow and flat top passband with intra band ripple less than 0.3 dB, 3 dB bandwidth of 4.8 GHz and out-of-band rejection of about 35 dB. The insertion loss of the filter is about -14 dB, including grating coupling loss about -6.5 dB and on-chip loss less than -1 dB. The heating power for center wavelength shift of the filter is about 89.4 mW per free spectral range (FSR). Relevant applications of such filters include optical information processing and microwave photonics.
绝缘体上铌酸锂（LNOI）是一种新型光子集成平台，它具有高光学限制能力，并保留了铌酸锂（LN）固有的优异特性。可调谐滤波器是集成光学中不可或缺的器件之一。在此，我们基于LNOI设计并制造了一种使用两个级联环形微环谐振器（MRR）的热光（TO）可调谐光学滤波器。该滤波器呈现出窄且顶部平坦的通带，带内纹波小于0.3 dB，3 dB带宽为4.8 GHz，带外抑制约为35 dB。该滤波器的插入损耗约为 -14 dB，包括光栅耦合损耗约 -6.5 dB和片上损耗小于 -1 dB。滤波器中心波长偏移的加热功率约为每自由光谱范围（FSR）89.4 mW。此类滤波器的相关应用包括光信息处理和微波光子学。
