An Integrated Gallium Phosphide Optical Parametric Amplifier

Optical parametric amplification is a promising alternative to traditional erbium-doped amplifiers, offering unidirectional, low-noise, and broadband amplification. Here we present an integrated continuous-traveling-wave parametric amplifier that surpasses existing technologies, achieving up to 35 dB of gain and up to 25 dB of net gain over a 140-nm-wide wavelength window centered at 1550 nm, thus covering S, C, and L telecommunication bands simultaneously. Our device utilizes a 5.55-cm-long spiral waveguide made of gallium phosphide, renowned for its high Kerr nonlinearity and large linear refractive index. These properties are key factors for efficient parametric amplification.