Femtosecond laser direct writing(Fs LDW)three-dimensional(3D)photonic integrated circuits(PICs)can realize arbitrary arrangement of waveguide arrays and coupling devices.Thus,they are capable of directly constructing ...Femtosecond laser direct writing(Fs LDW)three-dimensional(3D)photonic integrated circuits(PICs)can realize arbitrary arrangement of waveguide arrays and coupling devices.Thus,they are capable of directly constructing arbitrary Hamiltonians and performing specific computing tasks crucial in quantum simulation and computation.However,the propagation constantβis limited to a narrow range in single-mode waveguides by solely changing the processing parameters,which greatly hinders the design of Fs LDW PICs.This study proposes a composite waveguide(CWG)method to increase the range ofβ,where a new single-mode composite waveguide comprises two adjacent circular waveguides.As a result,the photon propagation can be controlled and the variation range ofβcan be efficiently enlarged by approximately two times(Δβ~36 cm-1).With the CWG method,we successfully realize the most compact Fs LDW directional couplers with a 9μm pitch in a straight-line form and achieve the reconstruction of the Hamiltonian of a Hermitian array.Thus,the study represents a step further toward the fine control of the coupling between waveguides and compact integration of Fs LDW PICs.展开更多
基金National Natural Science Foundation of China(61825502,62131018)Major Science and Technology Projects in Jilin Province(20220301002GX)+1 种基金National Key Research and Development Program of China(2021YFF0502700)China Postdoctoral Science Foundation(2019M651200)。
文摘Femtosecond laser direct writing(Fs LDW)three-dimensional(3D)photonic integrated circuits(PICs)can realize arbitrary arrangement of waveguide arrays and coupling devices.Thus,they are capable of directly constructing arbitrary Hamiltonians and performing specific computing tasks crucial in quantum simulation and computation.However,the propagation constantβis limited to a narrow range in single-mode waveguides by solely changing the processing parameters,which greatly hinders the design of Fs LDW PICs.This study proposes a composite waveguide(CWG)method to increase the range ofβ,where a new single-mode composite waveguide comprises two adjacent circular waveguides.As a result,the photon propagation can be controlled and the variation range ofβcan be efficiently enlarged by approximately two times(Δβ~36 cm-1).With the CWG method,we successfully realize the most compact Fs LDW directional couplers with a 9μm pitch in a straight-line form and achieve the reconstruction of the Hamiltonian of a Hermitian array.Thus,the study represents a step further toward the fine control of the coupling between waveguides and compact integration of Fs LDW PICs.
