Low-loss fiber-to-chip interface for lithium niobate photonic integrated circuits

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journal

15 Scopus Citations
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Author(s)

  • Lingyan HE
  • Mian ZHANG
  • Amirhassan SHAMS-ANSARI
  • Rongrong ZHU
  • Lončar Marko

Detail(s)

Original languageEnglish
Pages (from-to)2314-2317
Journal / PublicationOptics Letters
Volume44
Issue number9
Online published26 Apr 2019
Publication statusPublished - 1 May 2019

Abstract

Integrated lithium niobate (LN) photonic circuits have recently emerged as a promising candidate for advanced photonic functions such as high-speed modulation, nonlinear frequency conversion, and frequency comb generation. For practical applications, optical interfaces that feature low fiber-to-chip coupling losses are essential. So far, the fiber-to-chip loss (commonly >10 dB∕facet) has dominated the total insertion losses of typical LN photonic integrated circuits, where on-chip losses can be as low as 0.03–0.1 dB/cm. Here we experimentally demonstrate a low-loss mode size converter for coupling between a standard lensed fiber and sub-micrometer LN rib waveguides. The coupler consists of two inverse tapers that convert the small optical mode of a rib waveguide into a symmetrically guided mode of a LN nanowire, featuring a larger mode area matched to that of a tapered optical fiber. The measured fiber-to-chip coupling loss is lower than 1.7 dB/facet with high fabrication tolerance and repeatability. Our results open the door for practical integrated LN photonic circuits efficiently interfaced with optical fibers.

Citation Format(s)

Low-loss fiber-to-chip interface for lithium niobate photonic integrated circuits. / HE, Lingyan; ZHANG, Mian; SHAMS-ANSARI, Amirhassan; ZHU, Rongrong; WANG, Cheng; Marko, Lončar.

In: Optics Letters, Vol. 44, No. 9, 01.05.2019, p. 2314-2317.

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journal