(a)
(b)
Figure 1: Angular spectrum of output signal beam (a) and idler beam (b) when pump phase is modulated. Dotted line: spatial walk-off effect not considered, a = 0.5. Dashed (solid) line: spatial walk-off effect considered, a = 0.2 (0.5). E0 = 10−6 (small-signal condition); crystal length L is 10 mm; LNL = 0.23L; Lsp = 5L; n = 4.