Spectrum of Φu(Ω) measured at the corresponding output port of PBS2.
(a,b) Spectral shape of the mode functions for τ = 0 (solid blue line) and τ = 100 as (dashed green line). In (a) the post-selection angle θ is 97.2°, so as to fulfil the condition ω0τ − Γ = π. In (b) the angle θ is 96.7°. (c) Shift of the centroid of the spectrum of the output pulse after projection into the polarisation state in PBS2, as a function of the post-selection angle θ. Green solid line: τ = 10 as; Dotted red line: τ = 50 as and dashed blue line: τ = 100 as. Label I corresponds to θ = 96.7° [mode for τ = 100 as shown in (b)]. Label II corresponds to θ = 97.2°, where the condition ω0τ − Γ = π is fulfiled [mode for τ = 100 shown in (a)]. It yields the minimum mode overlap between states with τ = 0 and τ ≠ 0. Data: λ0 = 1.5 μm and T0 = 100 fs.