An analysis of amplified recirculating structures for producing a pseudo-co
ntinuous wave, PCW, signal is presented. Experimentations with amplificatio
n provided by EDFA and SOA are shown. Both the hold-on function and the swi
tch-off function are analyzed. The comparison between structures with diffe
rent amplifiers shows better duration performances for EDFAs, but faster al
l-optical operation capabilities for SOAs. (C) 1999 Elsevier Science B.V. A
ll rights reserved.