Fabrication of Low Loss Lithium Niobate Rib Waveguides Through Photoresist Reflow
Fabrication of Low Loss Lithium Niobate Rib Waveguides Through Photoresist Reflow
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DOI：
10.1109/jphot.2022.3222184
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发表时间：
2022-12
影响因子：
2.4
通讯作者：
K. Prabhakar;R. Reano
中科院分区：
文献类型：
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作者：
K. Prabhakar;R. Reano
我们目前的光刻和氩等离子体刻蚀的绝缘体上的锂的氧化物（LNOI）的脊形波导使用回流光刻胶蚀刻掩模和405 nm光刻。在大大超过其玻璃化转变温度的温度下熔化光致抗蚀剂，同时通过光致抗蚀剂粘附控制使特征变形最小化，降低了侧壁表面粗糙度，并允许光致抗蚀剂既用作图案掩模又用作硬蚀刻掩模。制作了具有亚nm均方根粗糙度的波导侧壁表面。侧壁粗糙度和角度特征宽度的依赖性，以及对制造的器件的热退火的传播损耗的特征。在制造的微谐振器上测量的品质因数超过一百万。具有低传播损耗的LNOI脊形波导和谐振器增加了非线性光学转换效率，并且对于有效的电光调制是有用的。低损耗LNOI光子集成电路的光刻兼容制造促进了可扩展的商业化。
We present lithography and argon plasma etching of lithium niobate on insulator (LNOI) rib waveguides using reflowed photoresist etch masks and 405 nm photolithography. Melting the photoresist at temperatures greatly exceeding its glass transition temperature while minimizing feature distortion through photoresist adhesion control reduces sidewall surface roughness and allows the photoresist to be used both as the pattern mask and the hard etch mask. Waveguide sidewall surfaces exhibiting sub-nm root mean square roughness are fabricated. Dependence of sidewall roughness and angle on feature width, and propagation loss on thermal annealing of the fabricated devices is characterized. Measured quality factors on fabricated microresonators exceed one million. LNOI rib waveguides and resonators with low propagation loss increase nonlinear optical conversion efficiencies and are useful for efficient electro-optic modulation. Photolithography compatible fabrication of low loss LNOI photonic integrated circuits facilitates scalable commercialization.