Characterization of a highly photorefractive RF-sputtered SiO2-GeO2 waveguide.
We present the characterization of highly photorefractive Er3+/Yb3+-doped 75SiO2-25GeO2 planar waveguides, single mode at 1550 nm, deposited by radio-frequency-magnetron-sputtering (RFMS) technique. Details of the deposition process are reported. The material presents an intense absorption band (alpha approximately 10;3/10;4 cm;-1) in the UV region. Irradiations by a KrF excimer laser source at lambda = 248 nm have produced large positive (up to 310-3) refractive index changes, without the need of particular sensitization procedures. Direct measurements of UV photo-induced volume densification demonstrates that glass compaction accounts for large part of the refractive index change. Highly efficient photo-induced phase gratings have thus been fabricated in the waveguide.
Sebastiani
S
S
Conti
G Nunzi
GN
Pelli
S
S
Righini
G
G
Chiasera
A
A
Ferrari
M
M
Tosello
C
C