A single monolithic transceiver chip for handling optical to electrical to optical conversion of optical WDM signals in an optical transmission network which has an optical WDM signal input for reception of a WDM signal and an optical WDM signal output for transmission of a WDM signal and a plurality of electrical signal outputs and a plurality of electrical signal inputs. The chip further comprises an integrated decombiner coupled to the optical signal input that separates the WDM signal into a plurality of separate optical channel signals, an integrated array of photodetectors that each receives a respective optical channel signal and that converts the optical channel signal into an electrical signal and that provides the converted electrical signals to the electrical signal outputs of the transceiver chip. The transceiver chip also includes an integrated array of laser sources that provide a plurality of optical outputs at different wavelengths, an integrated array of electro-optic modulators that each modulate a respective optical output from a laser source with an electrical signal received from the electrical signal inputs of the chip to provide a plurality of modulated optical channel signals and an integrated optical combiner that receives the modulated optical channel signals and combines them into a single WDM signal that is provided at the optical WDM signal output.