Highly Accurate Docking of a Photonic Crystal Nanolaser to a SiN (x) Waveguide by Transfer Printing

We propose and demonstrate an improved method for transferprintingthat allows for the accurate docking of a photonic crystal nanobeam(NB) laser onto a SiN (x) waveguide. Ourproposed method enables achieving much smaller transfer printing misalignmentscompared to the conventional approach based on visual alignment inexperiments. We tested our method by docking a modified NB laser designwith a theoretical unidirectional coupling efficiency of 64% to theSiN (x) waveguide. The results show a meanrotational misalignment of only 0.08 & DEG; and a mean displacementmisalignment of 26 nm for 48 NB lasers docked at the SiN (x) waveguides, demonstrating the high accuracy andexcellent transfer printing reproducibility of our proposed method.Additionally, measurements indicated that over 97% of these highlyaccurate docked NB lasers exhibited uniform unidirectional couplingto specific waveguide output facets. We believe that the improvedtransfer printing steps presented in this study, along with the correspondinghybrid integration of docking NB lasers at the SiN (x) waveguide, provide a highly promising method for accuratelyintegrating nanowire-based light sources into silicon-based photonicintegrated circuits.