The present disclosure is directed to an optical apparatus suitable for coupling to an optical network. The optical apparatus is adapted to transmit multiplexed optical signals on the optical network and/or de-multiplex optical transmissions from the network. The optical apparatus includes an optical waveguide and an optoelectronic device. The optical waveguide has a set of diffractive elements in the form of a scribed volume hologram, which provides an optical transfer function. The optical waveguide also includes a first optical port and a second optical port. The second optical port is adapted to be optically coupled to the optical network. The optoelectronic device includes a plurality of optical portions. The optoelectronic device is adapted to convert optical signals at the optical portions into electric signals and/or convert electric signals into optical signals at the optical portions.