Experimental results are presented for a study of the stability regime of an actively mode-locked polarization-maintaining fiber ring laser used as a memory. Observations indicate that the pulse widths in the memory can be reduced (by soliton effects) by a factor of approximately 4.4 below the pulse widths predicted by standard active mode-locking theory. Stability regions for the solitons are mapped and compared with theoretical predictions. (C) 1996 Optical Society of America.