Surface plasmonic bismuth ion-doped waveguide with black phosphorus cladding.

In this paper, a waveguide device with bismuth ion (Bi)-doped glass as the core and black phosphorus acting as the cladding is theoretically proposed. Finite-difference time-domain and numerical methods are used to elucidate the waveguide dispersion characteristics, elaborate the transverse-electric mode profiles, solve the characteristic eigenvalue equations, and calculate the gain/noise figure characteristics of the guiding medium. The numerical results show that the mode confinement factor for the fundamental mode with h=5  μm can reach 99.8%. The analytical results also indicate that with pump power fixed at 100 mW, the active ion concentration fixed at 2×10  ion/m, the gain and noise figure of a waveguide device with 0.10 m length are 34 dB and 3.38 dB, respectively. The proposed waveguide device is a promising candidate as a building block for various integrated photonic circuits.