Patent ID: 7565045

Claim:
A tuning light source apparatus comprising: an optical resonator filter including a multiple-optical resonator in which a plurality of optical resonators of different light path lengths is connected, the optical resonators comprising: a first optical resonator positioned at a light input/output side of the optical resonator filter; a second optical resonator positioned at a reflection side of the optical resonator filter; a third optical resonator positioned between the first and the second optical resonators; a light supply device for supplying light to the optical resonator filter at the light input/output side of the optical resonator filter; a tuning device for changing a resonance wavelength of the multiple-optical resonator; a first light detection device for detecting an oscillation light output to outside from an output port of the optical resonator filter, the output port located at the light input/output side of the optical resonator filter; a plurality of additional light detection devices for detecting light deviated from corresponding resonator paths of the optical resonator filter output from corresponding through ports of the optical resonator filter, the additional light detection devices comprising: a first additional light detection device to detect light deviated from a first resonator path of the optical resonator filter output from a first through port of the optical resonator filter, the first resonator path located at the light input/output side of the optical resonator filter, the first additional light detection device to detect the light output by the light supply device through the first resonator path that does not reach the first, the second, and the third optical resonators; a second additional light detection device to detect light deviated from a second resonator path of the optical resonator filter output from a second through port of the optical resonator filter, the second resonator path located between the first and the second optical resonators, the second additional light detection device to detect the light output by the light supply device through the first and the second resonator paths and the first optical resonator that does not reach the second and the third optical resonators; a third additional light detection device to detect light deviated from a third resonator path of the optical resonator filter output from a third through port of the optical resonator filter, the third resonator path located at the reflection side of the optical resonator filter, the third additional light detection device to detect the light output by the light supply device through the first, the second, and the third resonator paths, and the first and the third optical resonators, that does not reach the second optical resonator; and a control unit for controlling the operation of the tuning device based on the lights detected by the first and the additional light detection devices.