Paul Dapkus
University of Southern California
ESI 2017 Quad Chart Paul Dapkus
A chip-scale oscillator that directly generates low phase-noise signals in the EHF-band (30-300GHz) can enable transformational advances in subsystem design for multiple NASA applications in telecommunication, remote sensing and navigation. Currently, microwave or mmW signals at the EHF-band are generated by frequency-multiplication from oscillators that deliver lower frequencies (e.g., at X-band), resulting in phase noise degradation and increased size, weight, and power (SWaP). Our project is concerned with the development of a photonic integrated circuit (PIC) that can directly generate a EHF-signal (the fundamental) from a regeneratively mode-locked (ML) laser. Leveraging the high quality-factor (Q) derived from the ML laser, we expect this fundamental EHF-signal to be of high spectral purity. Furthermore, we can program the PIC to synthesize additional EHF frequencies that are harmonics of the fundamental via optical heterodyning. This is accomplished by filtering pairs of lines from the optical comb emitted by the ML laser, and then photodetecting them with a wideband detector. We plan to maximize the spectral width of this optical comb via use of on-chip pulse compression, so that the frequencies covering the entire EHF-band can be synthesized by optical heterodyning.