This paper describes the advantages that the introduction of photonic integration technologies can bring to the development of photonic-enabled wireless communications systems operating in the millimeter wave frequency range. We present two approaches for the development of dual wavelength sources for heterodyne-based millimeter wave generation realized using active/passive photonic integration technology. One approach integrates monolithically two distributed feedback semiconductor lasers along with semiconductor optical amplifiers, wavelength combiners, electro-optic modulators and broad bandwidth photodiodes. The other uses a generic photonic integration platform, developing narrow linewidth dual wavelength lasers based on arrayed waveguide gratings. Moreover, data transmission over a wireless link at a carrier wave frequency above 100 GHz is presented, in which the two lasers are free-running, and the modulation is directly applied to the single photonic chip without the requirement of any additional component.

A monolithically integrated photonic source for tuneable mmwave signal generation has been fabricated. The source consists of 14 active components, i.e. semiconductor lasers, amplifiers and photodetectors, all integrated on a 3 mm 2 InP chip. Heterodyne signals in the range between 85 GHz and 120 GHz with up to -10 dBm output power have been successfully generated. By optically injection locking the integrated lasers to an external optical comb source, high-spectral-purity signals at frequencies >100 GHz have been generated, with phase noise spectral density below -90 dBc/Hz being achieved at offsets from the carrier greater than 10 kHz.

A monolithically integrated tunable heterodyne source designed for the generation and modulation of subterahertz signals is demonstrated. Distributed feedback lasers, semiconductor optical amplifier amplifiers, passive waveguides, beam combiners, electro-optic modulators, and high-speed photodetectors have been monolithically integrated on the same InP-based platform. Millimeter wave generation at up to 105 GHz based on heterodyning the optical tones from two integrated lasers in the integrated high bandwidth unitraveling-carrier photodetector has been demonstrated. This photonic integrated chip was used in a 100-Mb/s OOK wireless transmission experiment using the integrated amplitude modulator.