We report, to the best of our knowledge, the first broadband polarization mode splitter (PMS) based on the adiabatic light passage mechanism in the lithium niobate (LiNbO₃) waveguide platform. A broad bandwidth of ~140 nm spanning telecom S, C, and L bands at polarization-extinction ratios (PER) of >20 dB and >18 dB for the TE and TM polarization modes, respectively, is found in a five-waveguide adiabatic coupler scheme whose structure is optimized by an adiabaticity engineering process in titanium-diffused LiNbO₃ waveguides. When the five-waveguide PMS is integrated with a three-waveguide “shortcut to adiabaticity” structure, we realize a broadband, high splitting-ratio (η_c) mode splitter for spatial separation of TE- (H-) polarized pump (700-850 nm for η_c>99%), TM- (V-) polarized signal (1510-1630 nm for η_c>97%), and TE- (H-) polarized idler (1480-1650 nm for η_c>97%) modes. Such a unique integrated-optical device is of potential for facilitating the on-chip implementation of a pump-filtered, broadband tunable entangled quantum-state generator.

中文翻译：

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铌酸锂集成绝热耦合器中的宽带片上偏振模式分离器

据我们所知，我们在铌酸锂（LiNbO ₃）波导平台中报告了第一个基于绝热光通过机制的宽带偏振模分离器（PMS）。在五波导绝热模式中，分别在大于20 dB和大于18 dB的极化消光比（PER）下，跨越电信S，C和L波段约140 nm的宽带宽通过绝热工程工艺在钛扩散的LiNbO ₃波导中优化结构的耦合器方案。当五波导PMS与三波导“快捷方式绝热”结构结合，我们实现宽带，高分割比（η _Ç），用于TE-（H-）偏振的泵浦（为700-850纳米的空间分离方式分离器η _ç > 99％），TM-（V-）极化信号（1510年至1630年纳米η _ç > 97％），和TE-（H-）偏振的惰轮（为1680至50年纳米η _ç模式> 97％）。这种独特的集成光学器件具有促进泵浦滤波，宽带可调谐纠缠量子态发生器在芯片上实现的潜力。