Advances in Photonic Technologies and Cryptographic Applications

Dear Colleagues,

Over the last few years, photonic technologies have experienced a number of dramatic technical advances, tackling the development of high-performance, low-footprint, and price-competitive solutions, which makes it nowadays a key enabling technology in optical networks. This research field not only embraces the classical communication systems but also enables the practical implementation of quantum cryptographic protocols over optical networks. From a classical perspective, the design and fabrication of lasers, high-speed optical modulators for high-order modulation formats, compact and fast coherent receivers, and nonlinear waveguides for phase-sensitive and -insensitive amplification are major photonic technological achievements, allowing the extensive deployment of optical networks.

Moreover, recently, quantum cryptographic systems have been using photonic technologies to boost the successful laboratory experiments in this research field to practical and real-world implementations. In practice, this comprises the integration of bulky optical components on photonic chips, allowing for the generation, manipulation, and detection of different degrees of freedom of individual photons or weak coherent states. Such capabilities require the design and fabrication of devices for quantum state generation, linear and non-linear manipulation of the light, and detection of nonclassical light on a single platform. This is a major achievement considering the integration of several different optical components into a unique chip, which leads to a considerable reduction in the insertion losses and to a unique phase stabilization when compared with bulk optical devices.

Consequently, this Special Issue aims to highlight the recent progress and trends in photonic technologies with applications in optical communications, ranging from classical to quantum domains. This issue will accept high-quality manuscripts reporting original research results and survey articles of exceptional merit, and it will present the readers of this journal with the most recent outcomes and trends in this fundamental research area.

Prof. Dr. Nuno Silva
Prof. Dr. Nelson Muga
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Applied Sciences is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

• optical modulation
• self-coherent detection
• phase-sensitive and -insensitive amplification
• programmable photonics
• nonlinear optics
• silicon photonics
• photonic integrated circuits
• quantum photonic state generation
• quantum detection
• quantum key distribution
• quantum random number generation
• quantum effects in optical waveguides
• quantum cryptography primitives, protocols, and algorithms
• digital signal processing supporting coherent detection