Crystalline fibers, referring to those fibers with crystalline core structures, represent a rapidly progressing field of specialty fiber optics and applications. This special kind of fiber includes single-crystal fibers (SCFs) fabricated from micro-pulling down (MPD) and laser-heated pedestal growth (LHPG) techniques in addition to crystal-derived fibers (CDFs) made from rod-in-tube (RIT) and melt-in-tube (MIT) methods.

Crystalline fibers are supposed to possess the merits of being both crystals and of having a long-thin type shape. Compared with glass, crystals allow higher rare-earth doped concentrations and show higher melting points, thermal conductivity, and laser-induced damage thresholds. Benefiting from their long-thin-type shape, crystalline fibers exhibit waveguiding properties. For SCFs, laser and sensing applications have been widely reported. For example, over 250 W of continuous wave laser output has been realized with Yb:YAG SCF. Fiber sensing with temperature range of over 1500 °C has been realized with sapphire SCF. With CDFs, increasingly more researchers are focusing on their applications in single-frequency fiber laser and fiber sensing. For example, 255 mW of single-frequency laser has been reported with Yb:YAG-derived silica fiber. Fiber sensing with temperatures of as high as 1000 °C has been realized with sapphire-derived silica fiber.

Although crystalline fibers have shown great potential theoretically and experimentally, there  many problems remain in both fiber fabrication and application. For example, how can we fabricate 4C (crystal core and crystal-clad) fibers, especially double-clad crystal fibers? Besides silica, is there any other glass suitable for the cladding of YAG crystal-derived fibers? The list goes on.

We invite scientists to submit papers which discuss their latest results concerning crystalline fiber fabrication and characterization (structure and quality, optical and physical properties) and their applications in lasers, optical sensors, nonlinear photonics, integrating photonics, scintillation detection, etc.

Prof. Zhaojun Liu
Prof. Zhixu Jia
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. Crystals is an international peer-reviewed open access monthly 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 2600 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.

• Single-crystal fibers (SCFs)
• Crystal-derived fibers (CDFs)
• Crystal–glass hybrid fibers
• Semiconductor–glass hybrid fibers
• Ceramic–glass hybrid fibers