Light guiding in oxidised porous silicon optical waveguides

Recent progress in integrated waveguides based on oxidized porous silicon

“…Variation of ±0.02 dB for the output signal due to inaccurate tuning and noise of the system was established by multiple measurements. The measurements made by this new method are in a good agreement with previously used techniques such as ''cut-off'' method and fiber probe scanning [4][5][6][7][8].…”

“…On the following oxidation this layer is expected to form a cladding layer OPS2. Next, three-step thermal oxidation was performed [3,4]. The process variation consists in an Sb ion implantation, thermal annealing that uses SiO 2 masking layer instead of Si 3 N 4 , and in the utilization of a more complex electrolyte with ethylene glycol instead of alcohol for the dissolvent.…”

“…The integration of optoelectronic components requires integrated optical waveguide (WG) to provide optical interconnections solving the silicon integrated circuits metal interconnect problem [2]. Integrated optical WG based on oxidized porous silicon (PS) has been proved to be well compatible with conventional silicon microelectronic technology [3][4][5][6]. The waveguide structure is realized by anodizing silicon wafer in HF acid through the openings in a mask to form PS, and a subsequent thermal oxidation to transform PS in oxidized porous silicon (OPS) that is densified by high-temperature annealing.…”

“…The modulation of the anodization process allows to modify the porosity of the initial PS and final OPS obtaining the refractive index jump between the core and the cladding layer. Low optical losses are essential to achieve optical integrated WG and by optimizing the fabrication process optical losses were decreased, first from 10 dB/cm to 3-5 dB/cm for P + -type silicon [4,5], and then down to 1 dB/cm for N + -type silicon [7,8]. Recently, a two-step anodization process has been developed and planar losses of 0.5 dB/cm in the visible range have been demonstrated [9].…”

Optical properties of erbium-doped porous silicon waveguides

“…In optical telecommunication application, using porous silicon (PS) material to form doped optical WG is an attractive solution [2]. In fact, porous silicon offers a large range of refractive indices and presents a high specific surface for erbium incorporation.…”