Planar Waveguide Structures for Post-EDFA Broadband Near Infrared Optical Amplifiers

This thesis reports on optical gain of up to 5.7 dB from a planar waveguide with core made of tetravalent chromium-doped calcium germanate single crystal

Effects of Post Treatments on Bismuth-Doped and Bismuth/ Erbium Co-doped Optical Fibres

Bismuth-doped and bismuth/erbium co-doped optical fibres have attracted much attention for their great potential in the photonic applications at ultrawide O, E, S, C and L bands. The effects of post treatments, including various heating, high energy ray radiation, laser radiation and H2 loading processes, on these fibres’ performance, functionality and stability have been experimentally studied. Experimental results demonstrate that these post treatments could allow us to get insights regarding the formation and the structure of bismuth active centre (BAC) and be used to control and regulate the formation of BAC

Bismuth

Bismuth—a wonder metal with unique features—plays an important role in the bismuth-related optoelectronic materials. The innovative development of bismuth optoelectronic materials will undoubtedly drive the social development and economic growth in the world towards a glorious future

Improving broadband emission within Bi/Er doped silicate fibres with Yb co-doping

© 2015 Optical Society of America. We present Bi/Er/Yb co-doped silicate fibre (BEYDF) which is fabricated by co-doping with Yb2O3 into Bi/Er doped silicate fibre (BEDF), and investigate its properties associated with Yb co-doping. Spectral absorption, emission, emission lifetime, ESA and gain characteristics of BEYDF are experimentally investigated and compared with those of BEDF to reveal particular impacts of Yb on the broadband spectral characteristics. We measured Yb3+ emissions at 980 nm and 1040 nm in BEYDF, and emissions related to Bi active centres (BACs, at 1100 nm and 1420 nm) and Er3+ (1530 nm) in BEYDF and BEDF under 830 nm pumping. Evidences of Yb3+→BAC energy transfer process, in addition to the normal Yb3+→Er3+ energy transfer process are noticed. Compared with BEDF, BEYDF has shown both broadened and enhanced emissions and gain. In particular, the overall emission bandwidth within a 4 dB intensity is attained over Δλ = (1000-1590) nm in BEYDF, and just over Δλ = (1250-1590) nm in BEDF. The overall emission intensity is enhanced by a factor of 2.5 in BEYDF over that of BEDF. Furthermore, Er3+ gain at 1530 nm is increased and BAC linked ESA at 1400 nm is reduced in BEYDF. Yb3+ related emissions and energy transfers from the excited Yb3+ to both the Er3+ and BACs can explain the improvements of emission and gain. These results indicate that Yb3+ co-doping can be used to expand and enhance broadband emissions and gain in BEYDFs

Bismuth-Doped Glass Microsphere Lasers

In this work, a hybrid structure consisting of a multicomponent germanate glass microsphere containing bismuth as a gain medium is proposed and presented. The bismuth-doped germanate glass microspheres were fabricated from a glass fiber tip with no precipitation of the bismuth metal. Coupling with a fiber taper, the bismuth-doped microsphere single-mode laser was observed to lase at around 1305.8 nm using 808 nm excitation. The low threshold of absorbed pump power at 215 μWmakes this microlaser appealing for various applications, including tunable lasers for a range of purposes in telecommunication, biomedical, and optical information processing

Luminescent Ions in Silica-Based Optical Fibers

We present some of our research activities dedicated to doped silica-based optical fibers, aiming at understanding the spectral properties of luminescent ions, such as rare-earth and transition metal elements. The influence of the local environment on dopants is extensively studied: energy transfer mechanisms between rare-earth ions, control of the valence state of chromium ions, effect of the local phonon energy on thulium ions emission efficiency, and broadening of erbium ions emission induced by oxide nanoparticles. Knowledge of these effects is essential for photonics applications

BAC Photobleaching in Bismuth-Doped and Bismuth/Erbium Co-Doped Optical Fibers

Bismuth-doped optical fiber (BDF) and bismuth/erbium co-doped optical fiber (BEDF) have attracted much attention due to their ultra-broadband luminescence in the near-infrared (NIR) region. The photobleaching effect on bismuth active centers (BACs) related to the NIR luminescence has been systematically investigated and summarized, in terms of irradiation intensity, irradiation wavelength, and temperature. All these findings not only give the deep insights into the fundamental structure of BACs but also provide an effective way to control the BACs. They play an important role for the development of BDF- and BEDF-based devices with high performance and stability under laser exposure in future

Luminescent Glass for Lasers and Solar Concentrators

Rare earth‐doped glasses find applications in numerous photonic devices including color displays, infrared solid‐state lasers, and indicators, among many. In this chapter, we will present and discuss several luminescent glasses doped with rare earth ions in their trivalent form (RE3+) with general background and technological perspectives. Initially, we begin with a short introduction of RE3+ electronic energy‐level structure in solids followed by the discussion of structural feature of glass lasers. While the lasing properties are mainly governed by the solubility of the ions and phonon interactions, the issue of ion interactions in solid hosts will be addressed since they hardly depend on the type of materials. Spectroscopic properties of Nd3+‐doped phosphate glasses are discussed in the framework of Judd‐Ofelt theory. Rare earth‐doped optical amplifiers are tackled from a technological point of view, as well as luminescent solar concentrators for enhancement of solar efficiency

Nonsilica Oxide Glass Fiber Laser Sources: Part I

Nonsilica oxide glasses have been developed and studied for many years as promising alternatives to the most used silica glass for the development of optical fiber lasers with unique features and properties. Depending on the glass former of choice, these glasses can offer very distinctive physical properties if compared to silica-based glasses. With regard to the development of photonic fiber devices, these key properties include low phonon energy, high rare-earth ion solubility, high optical nonlinearity and easy handling procedures. This chapter, part I of a detailed study concerning nonsilica oxide glass–based optical fiber laser sources, reviews the main properties of three different nonsilica oxide glass families, namely phosphate, germanate and tellurite. The manufacturing process of an optical fiber using these glass materials is also discussed in Section 3 of this chapter