Coherent Tunneling by Nonadiabatic Passage in a Three-Waveguide Coupler

High-fidelity resonant tunneling passage in three-waveguide system

“…However, the tunneling transfer discussed in this paper depends on the non-eigenstate analyzed in Ref. [31]. In quantum mechanics, if a system evolves on its eigenstates, such an evolution is adiabatic.…”

“…are the distances between two outer waveguides and the central waveguide, respectively. [31] Ω = 1.789 mm −1 , γ = 0.7759 µm −1 , and a 0 = 9 µm are determined experimentally. [32] The refractive index profile n w (x, y) of each channel fabricated by ion exchange technique [37] is expressed as follows (see Fig.…”

“…On the dark-bright basis, the STIRAP-like equation ( 1) is solved analytically and simply. [36] The corresponding propagator for the nonadiabatic tunneling passage in a single threewaveguide system reads [31] 𝑈 (θ , A)…”

“…For a single three-waveguide subsystem, the beam power in channel C vanishes at the output when A i = π. [31] If we consider an N-stage three-waveguide system and substitute A i = π into Eqs. ( 4) and ( 6)-( 8), the analytic solutions to the final beam power at the output port read as follows.…”

“…[28][29][30] In this paper, the tunneling dynamics in each subsystem is based on non-eigenstate, and the tunneling passage is nonadiabatic. [31] The STIRAP scheme was used to design the waveguide couplers with high tunneling efficiency. [5] No matter whether the amplitudes and widths of the tunneling rates or the distance between two peak tunneling rates changes, the nonadiabatic tunneling exists and the fidelity of the STIRAP is near the benchmark 10 −4 of QIP.…”