Broadband on-chip polarization mode splitters in lithium niobate integrated adiabatic couplers

Hung Pin Chung, Chieh Hsun Lee, Kuang Hsu Huang, Sung Lin Yang, Kai Wang, Alexander S. Solntsev, Andrey A. Sukhorukov, Frank Setzpfandt, Yen Hung Chen

Research output: Contribution to journalArticlepeer-review

22 Scopus citations


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 (ηc) mode splitter for spatial separation of TE- (H-) polarized pump (700-850 nm for ηc>99%), TM- (V-) polarized signal (1510-1630 nm for ηc>97%), and TE- (H-) polarized idler (1480-1650 nm for ηc>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.

Original languageEnglish
Pages (from-to)1632-1645
Number of pages14
JournalOptics Express
Issue number2
StatePublished - 21 Jan 2019


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