Abstract: A self-seeded optical parametric amplifier (OPA) system includes a cavity mirror, a wavelength conversion unit, and a dichroic filter. The cavity mirror is configured to allow high transmission for an input laser beam and high reflection for a feedback beam. The wavelength conversion unit is configured to convert the input laser beam into a signal laser beam and an idler laser beam. The dichroic filter is configured to allow one of the signal laser beam and the idler laser beam to pass through the dichroic filter and reflect the other one onto a feedback path.

Abstract: A cavity-enhanced frequency mixer includes an input optical fiber, a waveguide, and an output optical fiber. The waveguide has an input end and an output end, the input end is connected to the input optical fiber, and a surface of the input end of the waveguide is coated with a highly reflective coating. The output optical fiber is formed with a fiber Bragg grating structure. The highly reflective coating and the fiber Bragg grating structure form a pair of reflective surfaces for resonant optical parametric oscillation under a low threshold situation, so that one of the beams generated by the input beam is reflected inside the partially reflective surfaces. Operated above a pump power threshold, the cavity-enhanced frequency mixer is tantamount to a compact, low-power budget optical parametric oscillator, while below the pump power threshold, it is a bright, compact, single-mode and narrow linewidth single-photon source.

Abstract: A method for optimizing a hyperfine aperiodic optical superlattice (HAOS) is provided. In the method, the HAOS is divided into a plurality of unit blocks with the same length, wherein the unit blocks has same spatial distribution of domain orientation, and the HAOS with an original conversion efficiency. The spatial distribution of domain orientation of one of the unit blocks is inverted. An achieved conversion efficiency of the HAOS with the inverted spatial distribution of domain orientation is calculated. The achieved conversion efficiency is compared with a target conversion efficiency. The HAOS with the achieved conversion efficiency which is closest to the target conversion efficiency as an optimized HAOS.