Figure 6. Formation of a broad PT soliton.

A broad Gaussian distribution populating the focusing band is excited. In the linear regime (a,b) the beam spreads, while in the nonlinear regime a broad double hump (c) or single hump (d) PT soliton forms which can propagate for 100 round trips. Note that for observing the single and double hump solitons the sign of the phase potential is switched between ϕ₀=−0.4π and ϕ₀=+0.4π, with G=1.4 for all cases. The estimated peak power in the experiment is about 2 mW for the nonlinear regime and below 0.5 mW for the linear regime.