Abstract: Disclosed are a quantum-entangled photon-pair light source using a chip-scale atomic ensemble and implementation method thereof. The quantum-entangled photon-pair light source may include an atomic vapor cell configured to generate cesium (Cs) vapor to fill a photon-pair chamber and a processor configured to cause a coupling laser and a pump laser to travel based on the photon-pair chamber and generate a photon pair of a signal and an idler from the atomic vapor cell.

Abstract: A method and a system for generating independent coherent photons frequency-stabilized to transition of atoms for long-distance quantum communication are provided. The method for generating independent coherent photons frequency-stabilized to transition of atoms for long-distance quantum communication according to the present disclosure, includes generating a photon in a quantum state from a first quantum light source including an alkali atom or an ensemble of alkali atoms therein as a medium, further generating a photon in a quantum state from a second quantum light source spatially separated from the first quantum light source, including the same medium as that of the first quantum light source therein, and oscillating a photon pair obtained by coupling the photons generated by the first and second quantum light sources as a continuous wave coherent photon (CWCP) for quantum communication.

Abstract: A method and a system for generating independent coherent photons frequency-stabilized to transition of atoms for long-distance quantum communication are provided. The method for generating independent coherent photons frequency-stabilized to transition of atoms for long-distance quantum communication according to the present disclosure, includes generating a photon in a quantum state from a first quantum light source including an alkali atom or an ensemble of alkali atoms therein as a medium, further generating a photon in a quantum state from a second quantum light source spatially separated from the first quantum light source, including the same medium as that of the first quantum light source therein, and oscillating a photon pair obtained by coupling the photons generated by the first and second quantum light sources as a continuous wave coherent photon (CWCP) for quantum communication.

Abstract: A method is disclosed for increasing an intensity of a signal detected in a spectroscopy device using a vapor cell and a spectroscopy device using the same. An operation method of the spectroscopy device may include: causing a first light for exciting an atom trapped in a vapor cell in a first hyperfine ground state to a first excited state to be incident on the vapor cell; causing a second light for exciting an atom trapped in the vapor cell in a second hyperfine ground state to a second excited state to be incident on the vapor cell; causing a third light for exciting the atom in the second excited state to a third excited state to be incident on the vapor cell; and detecting fluorescence which is emitted while the atom in the third excited state returns to the ground state.

Abstract: A method is disclosed for increasing an intensity of a signal detected in a spectroscopy device using a vapor cell and a spectroscopy device using the same. An operation method of the spectroscopy device may include: causing a first light for exciting an atom trapped in a vapor cell in a first hyperfine ground state to a first excited state to be incident on the vapor cell; causing a second light for exciting an atom trapped in the vapor cell in a second hyperfine ground state to a second excited state to be incident on the vapor cell; causing a third light for exciting the atom in the second excited state to a third excited state to be incident on the vapor cell; and detecting fluorescence which is emitted while the atom in the third excited state returns to the ground state.

Abstract: The present invention relates to an optical frequency synthesizer and an optical frequency synthesizing method using femtosecond laser optical injection locking, which inject a femtosecond laser optical frequency comb into a diode laser, thus obtaining single-mode laser light, phase-locked to only a single mode in the optical frequency comb, and which change the optical frequency and interval, that is, the repetition rate, of a femtosecond laser, together with the frequency of a semiconductor laser, thus scanning optical frequencies while realizing a single desired optical frequency. The optical frequency synthesizer using femtosecond laser optical injection locking, includes a mode-locked femtosecond laser (110), which is a master laser, and a diode laser (120), which is a slave laser and into which laser light emitted from the femtosecond laser is injected.

Abstract: Provided is a fiber ring laser capable of obtaining a back-up laser light and standard light having a wavelength continuously tuned in a single mode with equal spacing of 12.5 GHz, 25 GHz, 50 GHz or 100 GHz recommended by ITU-T Recommendation G. 692 & G. 694.1 in a C-band and an L-band using a fiber tunable etalon filter, an air gap etalon filter and a saturable absorber in an optical fiber laser resonator having a serial ring shape using a C-band optical amplifier and an L-band optical amplifier. The fiber ring laser can generate laser light having a wavelength tuned by more than 70 nm, excellent output power flatness and a source spontaneous emission ratio of more than 70 dB in 361 channels with equal spacing of 25 GHz by applying a bias voltage to a voltage-operated piezoelectric element of a tunable etalon filter. A single longitudinal mode operation of the fiber ring laser can be obtained by using a saturable absorber serving as a narrow-bandwidth filter.

Abstract: The present invention relates to an optical frequency synthesizer and an optical frequency synthesizing method using femtosecond laser optical injection locking, which inject a femtosecond laser optical frequency comb into a diode laser, thus obtaining single-mode laser light, phase-locked to only a single mode in the optical frequency comb, and which change the optical frequency and interval, that is, the repetition rate, of a femtosecond laser, together with the frequency of a semiconductor laser, thus scanning optical frequencies while realizing a single desired optical frequency. The optical frequency synthesizer using femtosecond laser optical injection locking, includes a mode-locked femtosecond laser (110), which is a master laser, and a diode laser (120), which is a slave laser and into which laser light emitted from the femtosecond laser is injected.