Patent ID: 7570350

Claim:
An optical arrangement for receiving a response signal returned from a device under test—DUT—in response to a stimulus signal received from a light source, comprising: a first splitter for receiving the response signal and for wavelength dependent splitting the response signal into a first partial signal and a second partial signal, a second splitter for receiving the second partial signal and for wavelength dependent splitting therefrom a third partial signal with a third spectral component, an optical detector for receiving the first partial signal and the third partial signal and detecting an optical power of the received signals, an optical shutter arranged to be moved to either let through to or block from the optical detector one of: the first partial signal and the third partial signal, and a first optical path for conducting the response signal from the DUT to the first splitter, a second optical path for conducting the second partial signal path from the first splitter to the second splitter, a third optical path for conducting the third partial signal from the second splitter, over the optical shutter to the first splitter, and a fourth optical path for conducting the first partial signal and the third partial signal to the optical detector.