Search

Near-stoichiometric planar and strip LiNbO3 optical waveguides were demonstrated using vapor transport equilibrium process and co-diffusion of titanium metal. Optical confinement is better in z-cut substrates than in x-cut substrates, and the waveguides were characterized optically. Spectral measurements, such as OH- absorption, optical absorption near the fundamental edge, and Raman scattering, were carried out to examine the Li-composition and crystalline phase inside and outside the guiding layer. The results have shown that the vapor transport equilibration process has brought these waveguides toward stoichiometric composition, the Li content inside and outside the waveguide layer is essentially identical, and the LiNbO3 phase is still retained within the waveguide layer. [ABSTRACT FROM AUTHOR]

Sm[sup 3+]-doped cadmium–aluminum–silicate glasses (CdO–Al[sub 2]O[sub 3]–SiO[sub 2]) have been fabricated and characterized optically. Intense visible lights and near-infrared emissions were observed under ultraviolet light and 488 nm laser excitation. The density, refractive index, optical absorption, Judd–Ofelt parameters, and spontaneous transition probabilities have been measured and calculated. Intense fluorescences at 1.2 and 1.29 μm wavelengths were observed, indicating that the glasses are promising materials for laser and optical amplifier applications operating in the 1.2–1.3 μm low-loss window of telecommunication fiber. © 2002 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Comments on the article of Jeongan Kang and colleagues about the emission characteristics of erbium-doped stoichiometric lithium niobate crystals. Preparation of the crystals by top-seeded solution growth method; Effects of vapor transport equilibration technique; Radiation trapping effect.

Frequency upconversion of Er[sup 3+] in alkali bismuth gallate glasses have been investigated. The upconversion mechanisms are discussed, and the dominant mechanisms are excited state absorption for the [sup 2]H[sub 11/2]→[sup 4]I[sub 15/2] and [sup 4]S[sub 3/2]→[sup 4]I[sub 15/2] transitions, and energy transfer upconversion for the [sup 4]F[sub 9/2]→[sup 4]I[sub 15/2] transition. Intense green (around 525-550 nm) and red (around 660 nm) emission bands were observed under 800 nm excitation. At a pump intensity of 15.6 W/cm2, frequency upconversion efficiencies of 2.1x10[sup -2] and 4.8x10[sup -3] were obtained for the green and red emissions, respectively. The results are the highest among doped oxide glasses, and are comparable to those reported for Er[sup 3+]/Yb[sup 3+] codoped fluoride glasses. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]