  In recent years, the use of integrated technologies for applications in the
field of quantum information processing and communications has made great
progress. The resulting devices feature valuable characteristics such as
scalability, reproducibility, low cost and interconnectivity, and have the
potential to revolutionize our computation and communication practices in the
future, much in the way that electronic integrated circuits have drastically
transformed our information processing capacities since the last century. Among
the multiple applications of integrated quantum technologies, this review will
focus on typical components of quantum communication systems and on overall
integrated system operation characteristics. We are interested in particular in
the use of photonic integration platforms for developing devices necessary in
quantum communications, including sources, detectors and both passive and
active optical elements. We also illustrate the challenges associated with
performing quantum communications on chip, by using the case study of quantum
key distribution - the most advanced application of quantum information
science. We conclude with promising perspectives in this field.
