Influence of phosphorous precursors on spectroscopic properties of Er³⁺-activated SiO₂-HfO₂-P₂O₅planar waveguides

Abstract

Abstract. (70-x)SiO 2 -30HfO 2 -хP 2 O 5 (х= 5, 10 mol %) glass planar waveguides activated by 0.5 mol% Er 3+ ions were prepared by sol-gel route. Several phosphorous precursors have been investigated for the synthesis of a dielectric stable sol useful for the realization of planar waveguides. The waveguides were investigated by different diagnostic techniques. The optical properties such as refractive index, thickness, number of propagating modes and attenuation coefficient were measured at 632.8 and 543.5 nm by prism coupling technique. Transmission measurements were carried out in order to assess the transparency of the deposited films. Photoluminescence measurements and lifetime decay curves of the Er 3+ transition ( 4 I 13/2 → 4 I 15/2 ) were performed in order to investigate the role of P 2 O 5 .

Luminescent Studies on Germanate Glasses Doped with Europium Ions for Photonic Applications

“…However, more interesting is the fact that the further increase of phosphate oxide has the opposite effect, whereby the asymmetric ratio increases. This phenomenon confirms that a higher concentration of P 2 O 5 leads to "depolymerization" of a glassy network, resulting from an increase in the non-bridging oxygen (NBO) group [37]. In this way, the phosphorous oxide can change its role from being a glass modifier to a glass-forming compound.…”

“…In our current research, we focused on the role of P 2 O 5 in luminescent and structural properties of GGB glasses doped with Eu 3+ ions. The phosphorous oxide is characterized by high phonon energy (1200 cm −1 ) and reduces clustering effects via non-bridging oxygen formation, better incorporating rare earth ions promoting more efficient emissions than pure germanate glasses [37]. Even more interesting is that the P 2 O 5 can be used as a nucleating agent for transparent glass-ceramic materials [38,39].…”

SiO 2 -P 2 O 5 -HfO 2 -Al 2 O 3 -Na 2 O glasses activated by Er 3+ ions: From bulk sample to planar waveguide fabricated by rf-sputtering

“…It is, thus, of technological and scientific importance, to define high efficient active materials and to develop a suitable fabrication protocols to realize active planar waveguides exhibiting low attenuation coefficients [2]. Since the amplification in EDWA has to be achieved in a length scale of few centimeters instead of some meters, as required for Er-doped fiber amplifiers, as consequence a high Er 3þ -doping concentrations are required where the possibility of clustering effects of the rare earths become important [3,4]. Considering this fact, SiO 2 based planar waveguides could be promising materials for EDWAs developing but the low solubility of rare earth in silica, due to the mismatch in size and valence between the rare earth ions and the constituents of the silica network, remain an issue [4].…”

“…Since the amplification in EDWA has to be achieved in a length scale of few centimeters instead of some meters, as required for Er-doped fiber amplifiers, as consequence a high Er 3þ -doping concentrations are required where the possibility of clustering effects of the rare earths become important [3,4]. Considering this fact, SiO 2 based planar waveguides could be promising materials for EDWAs developing but the low solubility of rare earth in silica, due to the mismatch in size and valence between the rare earth ions and the constituents of the silica network, remain an issue [4]. Possible way to increase the amounts of rare earth ions in the matrix avoiding or reducing clustering effects is the addition of co-doping agents, such as P 2 O 5 or A1 2 O 3 [5,6] and the crucial role of the Al ions in P 2 O 5 -SiO 2 matrix on the spectroscopic features of rare earth ions is already demonstrated [7].…”