US 12,230,934 B2
Laser oscillator
Shinichi Saito, Tokyo (JP)
Assigned to HITACHI, LTD., Tokyo (JP)
Filed by Hitachi, Ltd., Tokyo (JP)
Filed on Mar. 7, 2022, as Appl. No. 17/687,750.
Claims priority of application No. 2021-136061 (JP), filed on Aug. 24, 2021.
Prior Publication US 2023/0075435 A1, Mar. 9, 2023
Int. Cl. H01S 3/067 (2006.01); G06N 10/40 (2022.01); H01S 3/10 (2006.01)
CPC H01S 3/06791 (2013.01) [G06N 10/40 (2022.01); H01S 3/06716 (2013.01); H01S 3/10061 (2013.01)] 14 Claims
OG exemplary drawing
 
1. A laser oscillator comprising:
a ring resonator including an optical fiber ring in which an optical fiber is connected in a ring shape;
an incident laser light control unit that enters a laser pulsed light as a qubit string on the ring resonator;
a laser light detection unit that detects a polarization state of the laser pulsed light oscillating by the ring resonator;
an optical amplifier that is connected to the optical fiber ring and maintains an amplitude of the laser pulsed light propagating through the optical fiber ring;
a first optical fiber that is connected with a first polarization controller, after changing a polarization state of the laser pulsed light being a first qubit and a second qubit, which are continuous to each other and extracted from the optical fiber ring at a predetermined branch ratio, by the first polarization controller, and couples the laser pulsed light whose polarization state has been changed with the laser pulsed light being the first qubit and the second qubit, which are continuous to each other and propagate on the optical fiber ring;
a second optical fiber that is connected with a second polarization controller, after changing a polarization state of the laser pulsed light being the first qubit and the second qubit, which are continuous to each other and extracted from the optical fiber ring at a predetermined branch ratio, by the second polarization controller, and couples the laser pulsed light whose polarization state has been changed with the laser pulsed light being the first qubit and the second qubit, which are continuous to each other and propagate on the optical fiber ring; and
a third optical fiber that is connected with a third polarization controller, after changing a polarization state of the laser pulsed light being the first qubit and the second qubit, which are continuous to each other and extracted from the optical fiber ring at a predetermined branch ratio, by the third polarization controller, and couples the laser pulsed light whose polarization state has been changed with the laser pulsed light being the first qubit and the second qubit, which are continuous to each other and propagate on the optical fiber ring,
wherein the polarization state of the laser pulsed light is represented as a state vector in a Poincaré sphere having an S1 axis, an S2 axis, and an S3 axis which are orthogonal to each other, the first polarization controller rotates the state vector representing the polarization state of the laser pulsed light as a rotation axis on the S1 axis, the second polarization controller rotates the state vector representing the polarization state of the laser pulsed light as a rotation axis on the S2 axis, and the third polarization controller rotates the state vector representing the polarization state of the laser pulsed light as a rotation axis on the S3 axis.