Like in every pulsed lasers, short enough pulses will lead to Fourier
limited line width. For intermediate pulse length, the limiting factor is
the thermal tuning of the device. The device heats up during the pulse
and its emission wavelength follows and sweeps. Optimum pulses of 5 to
15 ns will enable to get a minimal linewidth.
Some customers such as the company Aerodyne published data on the linewidth reachable using our devices and electronics (Starter Kit).
Please have a look at (http://www.alpeslasers.ch/Conference-Papers/Workshop-Freiburg-01.pdf)
which describes measured line width in pulsed operation.
The standard measurement setup we use enables to verify that the laser is single mode i.e. has a linewidth not exceeding 0.3/cm.