Interleavers

The chapter describes principles, analysis, design, properties, and implementations of optical frequency (or wavelength) interleavers. The emphasis is on finite impulse response devices based on cascaded Mach-Zehnder-type filter elements with carefully designed coupling ratios, the so-called resonant couplers. Another important class that is discussed is the infinite impulse response type, based on e.g. Fabry-Perot, Gires-Tournois, or ring resonators

Nonlinear Integrated Microwave Photonics

Harnessing nonlinear optical effects in a photonic chip scale has been proven useful for a number of key applications in optical communications. Microwave photonics can also benefit from the adoption of such a technology, creating a new concept of nonlinear integrated microwave photonics. Here, we discuss the potential of on-chip nonlinear processing towards the creation of robust and multifunctional microwave photonic (MWP) processors. We also highlight key recent results in the field, including frequency agile MWP filters and ultra-wideband signal generators.Comment: 5 pages, 3 figures, invited paper at 2013 IEEE Topical Meeting on Microwave Photonic

Path-entangled photon sources on nonlinear chips

© 2016 The Authors Photon entanglement has a range of applications from secure communication to the tests of quantum mechanics. Utilizing optical nonlinearity for the generation of entangled photons remains the most widely used approach due to its quality and simplicity. The on-chip integration of entangled light sources has enabled the increase of complexity and enhancement of stability compared to bulk optical implementations. Entanglement over different optical paths is uniquely suited for photonic chips, since waveguides are typically optimized for particular wavelength and polarization, making polarization- and frequency-entanglement less practical. In this review we focus on the latest developments in the field of on-chip nonlinear path-entangled photon sources. We provide a review of recent implementations and compare various approaches to tunability, including thermo-optical, electro-optical and all-optical tuning. We also discuss a range of important technical issues, in particular the on-chip separation of the pump and generated entangled photons. Finally, we review different quality control methods, including on-chip quantum tomography and recently discovered classical-quantum analogy that allows to characterize entangled photon sources by performing simple nonlinear measurements in the classical regime