This paper reports on the construction and characterisation of a novel
double-pass confocal scanning microscope that uses a four-port fibre
coupler. The new imaging system is self-aligned, compact, vibration-fr
ee, and purely coherent. Compared with fibre-optic transmission- and r
eflection-mode confocal systems, the fibre-optic double-pass confocal
imaging system exhibits higher resolution. (C) 1998 Elsevier Science L
td. All rights reserved.