Alkaline aluminum phosphate glasses for thermal ion-exchanged optical waveguide

摘要

Alkaline aluminum phosphate glasses (NMAP) with excellent chemical durability for thermal ion-exchanged optical waveguide have been designed and investigated. The transition temperature Tg (470 ℃) is higher than the ion-exchange temperature (390 ℃), which is favorable to sustain the stability of the glass structure for planar waveguide fabrication. The effective diffusion coefficient D_e of K~+-Na~+ ion exchange in NMAP glasses is 0.110 μm~2/min, indicating that ion exchange can be achieved efficiently in the optical glasses. Single-mode channel waveguide has been fabricated on Er~(3+)/Yb~(3+) doped NMAP glass substrate by standard micro-fabrication and K~+-Na~+ ion exchange. The mode field diameter is 9.6 μm in the horizontal direction and 6.0 μm in the vertical direction, respectively, indicating an excellent overlap with a standard single-mode fiber. Judd-Ofelt intensity parameter Ω_2 is 5.47 × 10~(-20) cm~2, implying a strong asymmetrical and covalent environment around Er~(3+) in the optical glasses. The full width at half maximum and maximum stimulated emission cross section of the ~4I_(13/2) → 4I_(15/2) are 30 nm and 6.80 × 10~(-21) cm~2, respectively, demonstrating that the phosphate glasses are potential glass candidates in developing compact optoelectronic devices. Pr~(3+), Tm~(3+) and Ho~(3+) doped NMAP glasses are promising candidates to fabricate waveguide amplifiers and lasers operating at special telecommunication windows.