Optical parametric amplifier

An optical parametric amplifier comprising:

• a first optical waveguide having two phase matching wavelengths λ1 and λ2 (λ1<λ2), the first optical waveguide configured to perform parametric amplification of a signal light group;
• and
• an excitation light generator configured to generate excitation light to be input to the first optical waveguide,
• wherein the phase matching wavelengths λ1 and λ2 are set to satisfy a relationship of λ1<λsi<λ2 with respect to a wavelength λsi (i=1, 2, 3, . . . ) of the signal light group,
• the excitation light generator configured to generate excitation light having a wavelength in the vicinity of λ1/2 and excitation light having a wavelength in the vicinity of λ2/2 and inputs the generated rays of excitation light to the first optical waveguide, and
• the first optical waveguide comprises non-linear optical crystal having a periodic polarization inversion structure having two polarization inversion periods Λλ1 and Λλ2, and when a refractive index of light having a wavelength λ1/2 in the first optical waveguide is represented by nλ1/2, a refractive index of light having a wavelength λ2/2 is represented by nλ2/2, a refractive index of light having a wavelength λ1 is represented by nλ1, and a refractive index of light having a wavelength λ2 is represented by nλ2, the polarization inversion periods Λλ1 and Λλ2 satisfy relationships of nλ1/2/(λ1/2)−2nλ1/λ1=1/Λλ1, and nλ2/2/(λ2/2)−2nλ2/λ2=1/Λλ2.

An optical parametric amplification method comprising:

• providing a first optical waveguide having two phase matching wavelengths λ1 and λ2 (λ1<λ2), the first optical waveguide configured to perform parametric amplification of a signal light group;
• generating excitation light having a wavelength in the vicinity of λ1/2 and excitation light having a wavelength in the vicinity of λ2/2;
• inputting the generated rays of excitation light to the first optical waveguide;
• and
• performing parametric amplification of the signal light group using the first optical waveguide,
• wherein the phase matching wavelengths λ1 and λ2 are set to satisfy a relationship of λ1<λsi<λ2 with respect to a wavelength λsi (i=1, 2, 3, . . . ) of the signal light group,
• the first optical waveguide comprises non-linear optical crystal having a periodic polarization inversion structure having two polarization inversion periods Λλ1 and Λλ2, and
• when a refractive index of light having a wavelength λ1/2 in the first optical waveguide is represented by nλ1/2, a refractive index of light having a wavelength λ2/2 is represented by nλ2/2, a refractive index of light having a wavelength λ1 is represented by nλ1, and a refractive index of light having a wavelength λ2 is represented by nλ2, the polarization inversion periods Λλ1 and Λλ2 satisfy relationships of nλ1/2/(λ1/2)−2nλ1/λ1=1/Λλ1, and nλ2/2/(λ2/2)−2nλ2/λ2=1/Λλ2.