The optical power penalty software analysis tool from Luna Technologies Inc. is based on a linear approach to modeling optical communications systems, whereby each passive component is characterized by its linear transfer function (LTF). Once this is known, its effect on any bit sequence is determined, and its final system performance can be predicted. Designed for use with the company's optical vector analyzer, the software allows the user to simulate component characteristics such as transmitter type, modulation rate, and receiver bandwidth and noise. These and the LTF data calculate a component's power penalty for any data rate. Advantages of the program include visual pass/fail inspection and estimation of achievable bit error rate.