High-efficiency dual-band-multiplexing three-port grating coupler on 220-nm silicon-on-insulator with 248-nm deep-UV lithography
Li-Rong Lilly Cheng, Simei Mao, Zhi Li, Xin Tu, H. Y. Fu
Abstract
We experimentally demonstrate a novel, to the best of our knowledge, three-port grating coupler (TPGC) for dual-wavelength-band operation. The TPGC can couple light to/from two ports for S/C-band with polarization diversity and a third port for O-band. Such a coupling scheme could be applied in an integrated wavelength-division-multiplexing passive optical network (PON) unit, benefiting a polarization-diverse receiver for downstream S/C-band and transmitter for upstream O-band. The device is fabricated on a multi-project wafer, with peak coupling efficiency measured to be <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mo>−</mml:mo> </mml:mrow> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mn>3.8</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 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mo>−</mml:mo> </mml:mrow> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mn>5.4</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> for O-band and S/C-band, respectively. We also present a proof-of-concept demonstration for 10-Gb/s PON transmission based on the TPGC.