We have developed and tested a photonic integrated circuit that contains DFB lasers, SOA amplifiers, passive waveguides, beam combiners, electro-optic modulators and high speed photodetectors. This device is used to generate a 90 GHz tone thanks to photomixing in the integrated photodiode of two optical tones. A wireless transmission of up to 1 Gbit/s with an open eye diagram is demonstrated. A solution to reduce the phase noise based on self-injection locking is demonstrated. It was used to lock the millimeter wave tone on its fifth sub-harmonic frequency resulting in a low phase noise, below −90 dBc/Hz at an offset frequency of 10 kHz.