Numerical calculations concerning pulse position-modulated (PPM) infin
ite (periodic) and finite trains of bright pulses in a single mode opt
ical fibre are presented. Use is made of an inherent feature of the be
am propagation method which yields truly periodic solutions. The solit
ons are organised into unit cells containing various numbers of solito
ns, and phase differences are permitted between them. A comparison bet
ween the behaviour of a group of solitons in a unit cell of a periodic
train and the same number of solitons, standing alone as a group, is
made. Generic plots for the maximum temporal displacement against the
position-modulation coding parameter are presented for both 8 and 16 b
it patterns.