C-band four-channel CWDM (de-)multiplexers on a thin film lithium niobate–silicon rich nitride hybrid platform
Yang Liu, Xingrui Huang, Huan Guan, Zhiguo Yu, Qingquan Wei, Zhongchao Fan, Weihua Han, Zhiyong Li
Abstract
A four-channel coarse wavelength division multiplexing (CWDM) (de)multiplexer on a thin film lithium niobate–silicon rich nitride hybrid platform has been designed, fabricated, and experimentally measured. Enabled by cascaded multimode waveguide Bragg gratings, the (de)multiplexer has a box-like spectral response, wide 1-dB bandwidth (10 nm), low excess loss ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mo><</mml:mo> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mn>1.08</mml:mn> </mml:mrow> <mml:mspace width="thickmathspace"/> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="normal">d</mml:mi> <mml:mi mathvariant="normal">B</mml:mi> </mml:mrow> </mml:math> ), and low channel cross talk ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mo><</mml:mo> <mml:mo>−</mml:mo> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mn>18</mml:mn> </mml:mrow> <mml:mspace width="thickmathspace"/> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="normal">d</mml:mi> <mml:mi mathvariant="normal">B</mml:mi> </mml:mrow> </mml:math> ). The central wavelengths of the (de-)multiplexer are 1531/1551/1571/1591 nm, which align to the wavelength grids stipulated by the standard ITU-T G.694.2.