The two beams from the beam splitter have different intensities
The beamsplitter acts to divide the lights intensity in a given ratio over a range of wavelengths, generating two beams with the same spectral composition, if not the same intensity. It is a crucial part of many optical experimental and measurement systems, such as interferometers, also finding widespread application in fibre optic telecommunications. A beam splitter (or beamsplitter, power splitter) is an optical device which can split an incident light beam (e. a laser beam) into two (or sometimes more) beams, which may or may not have the same optical power (radiant flux). The ratio of reflected to transmitted light can vary based on the design of the beam splitter.
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