All-optical high-speed modulation of THz transmission through silicon core optical fibers

Investigation of Silicon Core-Based Fiber Bragg Grating for Simultaneous Detection of Temperature and Refractive Index

In this article, we theoretically designed and simulated a silicon core fiber for the simultaneous detection of temperature and refractive index. We first discussed the parameters of the silicon core fiber for near single-mode operation. Second, we designed and simulated a silicon core-based fiber Bragg grating and applied it for simultaneous sensing of temperature and environmental refractive index. The sensitivities for the temperature and refractive index were 80.5 pm/°C and 208.76 dB/RIU, respectively, within a temperature range of 0 to 50 °C and a refractive index range of 1.0 to 1.4. The proposed fiber sensor head can provide a method with simple structure and high sensitivity for various sensing targets.

All-fibre heterogeneously-integrated frequency comb generation using silicon core fibre

Originally developed for metrology, optical frequency combs are becoming increasingly pervasive in a wider range of research topics including optical communications, spectroscopy, and radio or microwave signal processing. However, application demands in these fields can be more challenging as they require compact sources with a high tolerance to temperature variations that are capable of delivering flat comb spectra, high power per tone, narrow linewidth and high optical signal-to-noise ratio. This work reports the generation of a flat, high power frequency comb in the telecom band using a 17 mm fully-integrated silicon core fibre as a parametric mixer. Our all-fibre, cavity-free source combines the material benefits of planar waveguide structures with the advantageous properties of fibre platforms to achieve a 30 nm bandwidth comb source containing 143 tones with <3 kHz linewidth, 12 dB flatness, and >30 dB OSNR over the entire spectral region.

Localised structuring of metal-semiconductor cores in silica clad fibres using laser-driven thermal gradients

The molten core drawing method allows scalable fabrication of novel core fibres with kilometre lengths. With metal and semiconducting components combined in a glass-clad fibre, CO2 laser irradiation was used to write localised structures in the core materials. Thermal gradients in axial and transverse directions allowed the controlled introduction, segregation and chemical reaction of metal components within an initially pure silicon core, and restructuring of heterogeneous material. Gold and tin longitudinal electrode fabrication, segregation of GaSb and Si into parallel layers, and Al doping of a GaSb core were demonstrated. Gold was introduced into Si fibres to purify the core or weld an exposed fibre core to a Si wafer. Ga and Sb introduced from opposite ends of a silicon fibre reacted to form III-V GaSb within the Group IV Si host, as confirmed by structural and chemical analysis and room temperature photoluminescence.

Recent progress of semiconductor optoelectronic fibers

Semiconductor optoelectronic fiber technology has seen rapid development in recent years thanks to advancements in fabrication and post-processing techniques. Integrating the optical and electronic functionality of semiconductor materials into a fiber geometry has opened up many possibilities, such as in-fiber frequency generation, signal modulation, photodetection, and solar energy harvesting. This review provides an overview of the state-of-the-art in semiconductor optoelectronic fibers, including fabrication and post-processing methods, materials and their optical properties. The applications in nonlinear optics, optical-electrical conversion, lasers and multimaterial functional fibers will also be highlighted.

Core opportunities for future optical fibers

Hair-thin strands of glass, intrinsically transparent and strong, of which many millions of kilometers are made annually, connect the world in ways unimaginable 50 years ago. What could another 50 years bring? That question is the theme of this Perspective. The first optical fibers were passive low-loss conduits for light, empowered by sophisticated sources and signal processing; a second advance was the addition of dopants utilizing atomic energy levels to promote amplification, and a third major initiative was physical structuring of the core-clad combinations, using the baseline silica material. Recent results suggest that the next major expansions in fiber performance and devices are likely to utilize different materials in the core, inhomogeneous structures on different length scales, or some combination of these. In particular, fibers with crystalline cores offer an extended transparency range with strong optical nonlinearities and open the door to hybrid opto-electronic devices. Opportunities for future optical fiber that derive from micro- and macro-structuring of the core phase offer some unique possibilities in ‘scattering by design’.