Abstract
A description is given of a confocal scanning microscope in which a two-mode optical fiber is used both to launch the light into the microscope and to detect the image signal. There is a discussion of the variety of imaging modes that result from variation of the combination of fiber modes used to launch and to detect the signal. The form of the three-dimensional transfer function is considered in all the cases, and the effect of the finite size of the fiber core is included.