Photonic devices (10 CFU)


Photonics is emerging in various areas of communications, electronics and sensors to support the need for transparency, speed, and ability to handle huge data streams and multiplexing, as request from the evolution of communication systems today. The course examines in detail the integrated optics sector, focusing on theoretical, technological and applicative aspects. We discuss various issues related to the perspective of photonics technologies, the actual and future markets and potentialities, the generic foundry scheme and, in detail, down to photonics devices: waveguides, passive devices such as filters and (de)multiplexers, modulators, integrated lasers and photodetectors, amplifiers and technologies and materials. When communications occur on very small scales as inside electronics chip, chip-to-chip or board-to-board then it comes to optical interconnects, an emerging field that will be the lifeblood of the future high speed electronic.

In particular, the course covers:

The perspective of photonics integration. Integrated optic for optical communications, sensors and optical interconnects (electronics). The generic foundry scheme in photonics. Technological platforms: glass on silicon, Lithium Niobate, Indium Phosphide, Silicon Photonics. The ubiquitous market of photonics devices. Potentialities and limits.

Optical components: Integrated-optic components. The propagation in planar guided-wave structures. Guided, radiative and leaky modes. The coupled mode theory. Bent waveguides, couplers and Y. Star couplers. Filters, (de)multiplexer and AWG. Switch. Integrated-optic modulators: phase and amplitude, novem modulation formats. Travelling wave electrodes. Fiber-optic grating: uniform, apodized and chirped. Fiber Bragg gratings. Isolator and circulator. Integrated Lasers and Phototodetectors.

Materials and technologies: Materials for integrated optic circuits. Electro-optical and magneto optical effects. Technologies for integrated optic circuits: glass on silicon, Lithium Niobate, Indium Phosphide and Silicon Photonics. The photorefractive effect and fiber Bragg gratings. Technological processes for the realization of passive components. Layer deposition, photolitography and etching. The packaging issue.

Optical circuits: The circuits for the photonic networks and switching. Components for Wavelength Division Networks. The wavelength routers. Switching fabric for optical signals. Add-drop and cross connects. Principles of optical signal processing. Components and circuits for EDFA and SOA. Gain and noise figure. SOA for optical signal processing. Optical time-domain reflectometry. Optical spectrum analyzer. Optical low-coherence interferometry.

Optical Interconnect: The interconnect problem. Analysis of the electrical interconnect and the optical alternative. Limits, advantages, constraints. From short range rack to rack to intra-chip links. Link performance (comparison). Integration technologies for combining optoelectronics, optics, and electronic integrated circuits: Silicon Photonics, Indium phosfide and Polymers. Monolithic vs hybrid solutions. CMOS compatible solutions.

Examples of data-intensive on-chip communication are considered and discussed: Luxtera (OptoPHY), IBM (TeraMux) and INTEL (LightPeak).