This paper highlights the study of carrier depletion effect on silicon waveguide with p-i-n diode and NPN structure. The device performance is predicted by using 2D Silvaco CAD software under different applied voltages. Device performances in terms of modulation efficiency will be discussed.

An analysis of silicon waveguide phase modulation efficiency based on carrier depletion effect

This paper highlights the study of carrier injection effect on silicon waveguide with p-i-n diode structure integrated on Silicon-on-Insulator (SOI). The device performance is predicted using 2D Silvaco CAD software under different applied voltages at wavelength 1.3 and 1.55 µm. Lπ and VπLπ is minimized at a greater applied voltage. Operating at 1.55 µm is proven to be more efficient in terms of length of the modulator, Lπ and modulation phase efficiency. At 0.75V, Lπ and VπLπ are 0.527711 cm and 0.39578 Vcm respectively. Meanwhile, at 1V, Lπ and VπLπ are 0.01303 cm and 0.013029Vcm respectively. Therefore, a greater voltage is suggested for a shorter device length and greater modulation efficiency.

On the modulation phase efficiency of a silicon p-i-n diode optical modulator

Silicon high-speed waveguide-integrated electro-optic modulator is one of the critical devices for on-chip optical networks. The device converts data from electrical domain to the optical domain. Most studies for high speed modulation method in Si or Si based device are based on free carrier concentration variations (injection or depletion of free carriers) which are responsible for local refractive index variations and then phase modulation of a guided wave traveling through the active region. A change in the refractive index/absorption can be achieved by injection or depletion of both electron and holes into the intrinsic region of a silicon p-i-n diode.

Free carrier absorption loss of p-i-n silicon-on-insulator (SOI) phase modulator

This paper reports the effect of doping concentration to the electrical characteristic performance of the phase modulator in the carrier injection mode at wavelength 1.55µm. The phase modulator device has been integrated in the silicon-on-insulator (SOI) rib waveguide with the p-i-n diode structure. The electrical device performance is predicted using the 2-D semiconductor package SILVACO (CAD) software under DC operation. The least doping concentration of p+ and n+ region produces the least change of refractive index of the modulator. Meanwhile, results show that by increasing the doping concentrations, the value of Iπ decreases. This means that the phase modulator performance is better with increased doping concentrations.

Various doping concentration effect on silicon-on-insulator (SOI) phase modulator

This paper presents the study of electrical characteristic of phase modulator in the carrier injection mode. The phase modulator device has been integrated in the silicon-on-insulator (SOI) rib waveguide by using the p-i-n diode structure. The electrical device performance is predicted by using the 2-D semiconductor package SILVACO (CAD) software under DC operation. In summary, the phase modulator device required 0.035mA drive current to get π phase shift at wavelength 1.55µm meanwhile 0.066mA drive current is required for the 1.3µm wavelength.

Phase modulator based on silicon-on-insulator (SOI) rib waveguide

Silicon is the most diffused material for microelectronic industry and, in recent times, it is becoming more and more
widespread in integrated optic and optoelectronic fields. We present the thermo-electro-optical analysis of an integrated
waveguide-vanishing-based optical modulator based on free-carrier dispersion effect, realizable on standard SOI wafer.
The optical behavior is based on the vanishing of the lateral confinement in the rib region, and consequent cut-off of the
propagating mode. Results show that an optical modulation depth close to 100% can be reached with a bandwidth of
about 154 MHz. Smart electrical driving, that is an injection overdrive of a few volts for a very short time, allows to
reach total ON-OFF switching time of about 860 ps. For that bias scheme the fall transient is then limiting the whole
dynamic and the resulting bit rate in a pure digital modulation scheme is about 1.2 Gb/s.

Iodice Mario

Papers

Analysis of a planar silicon opto-electronic modulator based on the waveguide-vanishing effect