Fundamental characteristics of a semiconductor ring laser (SRL) as an optic
al inertial rotation sensor were reported. An SRL used for experiments had
a small semiconductor gain block in a fiber external cavity, Beat frequency
was measured by the terminal voltage change of an SRL as a function of the
rotation rate, changing the loop radius of an SRL and the turn number of t
he fiber loop for investigating the detection characteristics. Detection se
nsitivity was proportional to the loop radius, and was independent of the t
urn number of the fiber loop. These experimental results verified that SRL'
s were operated as active ring laser gyroscopes based on the Sagnac effect.
Furthermore, we verified that lock-in phenomenon was one of the most domin
ant noise sources.