Optics and photonics are among the key technologies of the 21st century and offer the potential for novel applications in areas as diverse as sensing and spectroscopy, analytics, monitoring, biomedical imaging and diagnostics, as well as optical communication technology, among others. The high degree of control over optical fields that is possible today, for example, by using micro-and nano-optics together with the tremendous capabilities of modern processing and integration technology, enables new optical measurement systems with enhanced functionality and unprecedented sensitivity. Such systems are thus attractive for a wide range of applications that have been previously inaccessible and may ultimately lead to the democratization of optics and photonics. This Special Issue aims to provide an overview on some of the most advanced application areas in optics and photonics and indicate the broad potential for the future. The Special Issue contains 15 papers which all underwent substantial peer-review under the guidelines of the MDPI Applied Sciences journal. The fifteen papers are divided into five categories: Fiber Optic Sensing, Optical Communication, Distributed Sensing, Optical Imaging and Laser Technology.