High-precision measurement of a propagation loss of low-loss single-mode optical waveguides on lithium niobate on insulator

Recently, low-loss (0.027 dB/cm) ridge waveguides have been demonstrated on lithium niobate on insulator (LNOI) by laser patterning followed by chemo-mechanical polishing. However, the fabricated waveguide supports multi-mode propagation due to the relatively large cross-sectional dimensions. Here, we report conversion of the multi-mode LNOI waveguides into single mode waveguides with a mode field size of ~2.5 μm with a cladding layer of Ta2O5. The propagation loss of the single mode waveguide is measured to be ~0.042 dB/cm. Most importantly, we show that this fabrication approach has allowed to fabricate meter-length long LNOI single mode waveguides of low propagation loss.

[1]  Ya Cheng,et al.  Lithium niobate micro-disk resonators of quality factors above 107. , 2018, Optics letters.

[2]  Ya Cheng,et al.  Fabrication of high-Q lithium niobate microresonators using femtosecond laser micromachining , 2015, Scientific Reports.

[3]  P. Xu,et al.  On-chip generation and manipulation of entangled photons based on reconfigurable lithium-niobate waveguide circuits. , 2014, Physical review letters.

[4]  Richard M. Osgood,et al.  Fabrication of single-crystal lithium niobate films by crystal ion slicing , 1998 .

[5]  Kerry J. Vahala,et al.  Ultra-Low-Loss Optical Delay Line on a Silicon Chip , 2011 .

[6]  Ya Cheng,et al.  Second harmonic generation in a high-Q lithium niobate microresonator fabricated by femtosecond laser micromachining , 2014, 1405.6473.

[7]  Junjie Li,et al.  High-Q lithium niobate microdisk resonators on a chip for efficient electro-optic modulation. , 2015, Optics express.

[8]  W. Sohler,et al.  Loss in low-finesse Ti:LiNbO3 optical waveguide resonators , 1985 .

[9]  Ingo Breunig,et al.  Cascaded second-order optical nonlinearities in on-chip micro rings. , 2017, Optics express.

[10]  Ya Cheng,et al.  Phase-Matched Second-Harmonic Generation in an On-Chip L i NbO 3 Microresonator , 2016 .

[11]  Qiang Lin,et al.  On-chip second-harmonic generation and broadband parametric down-conversion in a lithium niobate microresonator. , 2017, Optics express.

[12]  J. Bowers,et al.  Ultra-low-loss Ta 2 O 5 -core/SiO 2 -clad planar waveguides on Si substrates , 2017 .

[13]  Arnan Mitchell,et al.  Status and Potential of Lithium Niobate on Insulator (LNOI) for Photonic Integrated Circuits , 2018 .

[14]  Ya Cheng,et al.  Long Low-Loss-Litium Niobate on Insulator Waveguides with Sub-Nanometer Surface Roughness , 2018, Nanomaterials.

[15]  Q. Gong,et al.  High-Q chaotic lithium niobate microdisk cavity. , 2018, Optics letters.

[16]  Xianfeng Chen,et al.  Cascading second-order nonlinear processes in a lithium niobate-on-insulator microdisk. , 2017, Optics letters.

[17]  L. Chrostowski,et al.  Silicon Photonics Design: From Devices to Systems , 2015 .

[18]  Ya Cheng,et al.  Fabrication of a multifunctional photonic integrated chip on lithium niobate on insulator using femtosecond laser-assisted chemomechanical polish. , 2019, Optics letters.

[19]  David A. B. Miller,et al.  Perfect optics with imperfect components , 2015 .

[20]  B. Sturman,et al.  Optical cleaning of congruent lithium niobate crystals , 2009 .

[21]  Ya Cheng,et al.  Chemo-mechanical polish lithography: A pathway to low loss large-scale photonic integration on lithium niobate on insulator , 2019, Quantum Eng..

[22]  Ya Cheng,et al.  High-Precision Propagation-Loss Measurement of Single-Mode Optical Waveguides on Lithium Niobate on Insulator , 2019, Micromachines.

[23]  Ya Cheng,et al.  High-Q Exterior Whispering-Gallery Modes in a Double-Layer Crystalline Microdisk Resonator. , 2019, Physical review letters.

[24]  Tzyy-Jiann Wang,et al.  Electro-optically tunable microring resonators on lithium niobate. , 2007, Optics letters.

[25]  Ya Cheng,et al.  Broadband Quasi-Phase-Matched Harmonic Generation in an On-Chip Monocrystalline Lithium Niobate Microdisk Resonator. , 2019, Physical review letters.

[26]  Yu-Ping Huang,et al.  High-extinction electro-optic modulation on lithium niobate thin film. , 2019, Optics letters.

[27]  Marko Loncar,et al.  Monolithic ultra-high-Q lithium niobate microring resonator , 2017, 1712.04479.