1,721,015 research outputs found
Ion-exchanged glass waveguide lasers and amplifiers
No full textIn this paper I will survey the field of ion-exchanged glass waveguide lasers and amplifiers. Ion-exchanged waveguide devices have significant virtues, such as low propagation losses and suitability for mass production. The progress in realising lasers and amplifiers has been impressive, but more work is needed to produce commercially viable devices
The erbium-doped planar amplifier: from laboratory to local loop
No full textI review the status of research into planar erbium-doped waveguide amplifiers, highlighting the challenges and prospects through examination of a typical application. Introduction: The erbium-doped fibre amplifier (EDFA) was invented at the University of Southampton in 1987, and rapidly recognised as a very significant advance. The first commercial EDFAs were available only four years later, making possible fully transparent transoceanic cables with unprecedented bandwidth and expanding the scope of land-based optical networks. Despite their unsurpassed performance, however, EDFAs remain expensive components whose cost must usually be shared among hundreds or even thousands of customers in order to make their use economically viable. They are thus to be found as head-end power amplifiers or booster amplifiers in trunk lines and submarine cables, but not in applications in the local loop
Neodymium-diffused lithium niobate waveguide lasers at 1084nm
No full textWe report the demonstration of waveguide lasers in LiNbO3 into which neodymium has been diffused. Optical feedback from the polished endfaces alone yielded an absorbed power threshold of 13 ± 3 mW, and a slope efficiency of 55 ± 8%
The photoluminescence of erbium-doped silicon monoxide
No full textFilms of silicon monoxide coevaporated with erbium are shown to produce strong room temperature photoluminescence peaked at 1535nm after annealing at 600°C. Decay measurements show a double exponential function with lifetimes of 0.41ms and 2.12ms, suggesting two distinct optically active erbium sites. Photoluminescence excitation spectroscopy between 700nm and 860nm reveals a monotonic increase in photoluminescence intensity towards shorter wavelengths. This result suggests that the transfer of energy from the pump source to the erbium ions is mainly via the recombination of electron-hole pairs (photocarriers) which are created by absorption within the SiO
Waveguide lasers operating at 1084nm in neodymium-diffused lithium niobate
Full text linkWe report the demonstration of waveguide lasers in lithium niobate into which the active element neodymium has been introduced by thermal diffusion. The waveguides were fabricated using conventional Ti indiffusion, and optical feedback was provided by the polished endfaces alone. The absorbed power threshold of one waveguide laser was estimated at 13±3 mW for pumping at 814 nm, and its slope efficiency in terms of total lasing output as a function of absorbed pump power was estimated to be 55±8%. Laser output powers in excess of 100 mW were observed
Integrated Q-switched multiple-cavity glass waveguide laser
No full textA novel Q-switching scheme, using rapid variation of the path difference between the cavities of a multiple-cavity resonator, is demonstrated. A thermo-optic phase modulator was used to switch the cavity loss of a Y-junction glass waveguide laser between high and low states. Q-switched pulses with durations of 5µs and peak powers of 70mW were obtained
Neodymium-diffused tunable Y-branch waveguide laser in LiNbO<sub>3</sub> operating at room temperature
No full textRare-earth-doped waveguide optical lasers and amplifiers have received considerable attention in recent years, both in fibre form and as channel waveguides on planar substrates. Channel waveguide geometries lend themselves ideally for applications in active integrated circuits, with the potential for photolithographic definition of complex-cavity devices and monolithically integrated modulators for tuning, line-narrowing, Q-switching and mode-locking
Tunable line-narrowed lasers employing Y-junction waveguide resonators
No full textRare-earth-doped planar waveguide lasers have been realised in many host materials, using a range of waveguide fabrication techniques. Recent advances in this technology exploit the advantages that planar devices have over fibre devices. In particular, electro-optic or thermo-optic modulators may readily be monolithically integrated, complex devices may be defined photolithographically, there is access to the modal fields for surface interactions, and waveguide geometries may be varied along the device for efficient interfacing to external components and for optimisation of individual components on an optical "chip"
Spectral properties of Er<sup>3+</sup>-doped chalcogenide glasses
No full textLanthanum sulphides glasses formed with sufficient proportions of Ga2S3 constitute a very convenient matrix for rare earth sulphides, and Pr3+-doped Ga2S3:La2S3 (GLS) glasses have been recognized as one of the most promising candidates for fibre amplifiers operating at a wavelength of 1.3µm. In this report, the spectral properties of chalcogenide glass of the molar composition 0.7Ga2S3:0.3La2S3 doped with Er3+ are presented and discussed. Emission and absorption spectra and lifetimes of energy levels have been measured. The 2.7µm emission, as shown below, has been observed from chalcogenide glass for the first time. Radiative and non-radiative transition rates are calculated and compared with the measured lifetimes of interesting energy levels
Ablated gratings on borosilicate glass by 193nm excimer laser radiation
No full textThe application of 193nm ArF excimer laser radiation to the fabrication of high-quality sub-micron relief gratings in Er/Yb-doped borosilicate glass using an interferometric system is presented. High quality relief gratings imprinted in silicate telecom glasses may find significant application in optical telecommunications or photonic band-gap fields in the near future. In particular, relief gratings applied to fibre or waveguide devices may provide high diffraction efficiencies over reduced dimensions compared with photorefractive gratings. Their straightforward application to a wide range of materials and the single step imprinting process are additional advantages. The ablation of BK-7 borosilicate glass using 193nm excimer laser radiation produces high quality surface etching when compared to 248nm radiation, prompting the use of this shorter wavelength for the fabrication of high-quality sub-micron structures
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