An undersea optical amplifier assembly, comprising: a water-tight housing; a photonic integrated circuited, PIC, disposed within the housing, the PIC including: a plurality of optical fiber inputs, each configured to receive an end of a respective optical fiber of a first fiber optic cable bundle; a plurality of optical fiber outputs, wherein each optical fiber output: corresponds to a respective optical fiber input to form a fiber optic input-output pair, and is configured to receive an end of a respective optical fiber of a second fiber optic cable bundle; and a plurality of optical amplifiers each optical amplifier optically coupled to each respective fiber optic input-output pair by a direct physical coupling comprising a first waveguide external to each optical amplifier, internal to the PIC, and coupling each fiber optic input to each respective optical amplifier, and a second waveguide external to the amplifier, internal to the PIC, and coupling each fiber optic output to each respective optical amplifier, such that each of the optical fibers of the first fiber optic cable bundle is physically coupled by the PIC to a respective one of the optical fibers of the second fiber optic cable bundle, and each optical amplifier including at least one semiconductor optical amplifier; a first water-tight access port configured to receive the first fiber optic cable bundle; and a second water-tight access port configured to receive a second fiber optic cable bundle. a water-tight housing; a photonic integrated circuited, PIC, disposed within the housing, the PIC including: a plurality of optical fiber inputs, each configured to receive an end of a respective optical fiber of a first fiber optic cable bundle; a plurality of optical fiber outputs, wherein each optical fiber output: corresponds to a respective optical fiber input to form a fiber optic input-output pair, and is configured to receive an end of a respective optical fiber of a second fiber optic cable bundle; and a plurality of optical amplifiers each optical amplifier optically coupled to each respective fiber optic input-output pair by a direct physical coupling comprising a first waveguide external to each optical amplifier, internal to the PIC, and coupling each fiber optic input to each respective optical amplifier, and a second waveguide external to the amplifier, internal to the PIC, and coupling each fiber optic output to each respective optical amplifier, such that each of the optical fibers of the first fiber optic cable bundle is physically coupled by the PIC to a respective one of the optical fibers of the second fiber optic cable bundle, and each optical amplifier including at least one semiconductor optical amplifier; a plurality of optical fiber inputs, each configured to receive an end of a respective optical fiber of a first fiber optic cable bundle; a plurality of optical fiber outputs, wherein each optical fiber output: corresponds to a respective optical fiber input to form a fiber optic input-output pair, and is configured to receive an end of a respective optical fiber of a second fiber optic cable bundle; and a plurality of optical amplifiers each optical amplifier optically coupled to each respective fiber optic input-output pair by a direct physical coupling comprising a first waveguide external to each optical amplifier, internal to the PIC, and coupling each fiber optic input to each respective optical amplifier, and a second waveguide external to the amplifier, internal to the PIC, and coupling each fiber optic output to each respective optical amplifier, such that each of the optical fibers of the first fiber optic cable bundle is physically coupled by the PIC to a respective one of the optical fibers of the second fiber optic cable bundle, and each optical amplifier including at least one semiconductor optical amplifier; corresponds to a respective optical fiber input to form a fiber optic input-output pair, and is configured to receive an end of a respective optical fiber of a second fiber optic cable bundle; and a plurality of optical amplifiers each optical amplifier optically coupled to each respective fiber optic input-output pair by a direct physical coupling comprising a first waveguide external to each optical amplifier, internal to the PIC, and coupling each fiber optic input to each respective optical amplifier, and a second waveguide external to the amplifier, internal to the PIC, and coupling each fiber optic output to each respective optical amplifier, such that each of the optical fibers of the first fiber optic cable bundle is physically coupled by the PIC to a respective one of the optical fibers of the second fiber optic cable bundle, and each optical amplifier including at least one semiconductor optical amplifier; a first water-tight access port configured to receive the first fiber optic cable bundle; and a second water-tight access port configured to receive a second fiber optic cable bundle.