  We propose a simple all-in-line single-shot scheme for diagnostics of
ultrashort laser pulses, consisting of a multi-mode fiber, a nonlinear crystal
and a CCD camera. The system records a 2D spatial intensity pattern, from which
the pulse shape (amplitude and phase) are recovered, through a fast Deep
Learning algorithm. We explore this scheme in simulations and demonstrate the
recovery of ultrashort pulses, robustness to noise in measurements and to
inaccuracies in the parameters of the system components. Our technique
mitigates the need for commonly used iterative optimization reconstruction
methods, which are usually slow and hampered by the presence of noise. These
features make our concept system advantageous for real time probing of
ultrafast processes and noisy conditions. Moreover, this work exemplifies that
using deep learning we can unlock new types of systems for pulse recovery.
