Patent ID: 7652770

Claim:
An optical nonlinear evaluation device comprising: a polarization Sagnac interference path provided with a Kerr medium that causes an optical nonlinear effect of causing a change in refractive index in accordance with light intensity; an optical pulse light source for supplying the polarization Sagnac interference path with a first signal beam polarized in a first direction; a first polarization beam splitter provided on the polarization Sagnac interference path so as to split the first signal beam into, a second signal beam polarized in a second direction and a third signal beam polarized in a third direction orthogonal to the second direction, to supply the second beam to a first side of the Kerr medium, and to supply the third beam to a second side of the Kerr medium; superimposing means for coaxially superimposing, onto either of the second signal beam traveling from the first polarization beam splitter to the first side of the Kerr medium and the third signal beam traveling from the first polarization beam splitter to the second side of the Kerr medium, a control beam that differs in optical characteristic from either of the second signal beam and the third signal beam; separating means for separating the control beam from either of the second and third signal beams having traveled through the Kerr medium; and detecting means provided so as to detect a phase difference between the second signal beam and the third signal beam.