Low-power-consumption short-length and high-modulation-depth silicon electrooptic modulator

Abstract

Abstract-In this paper, we propose and analyze a novel compact electrooptic modulator on a silicon-on-insulator (SOI) rib waveguide. The device confines both optical field and charge carriers in a micron-size region. The optical field is confined by using a planar Fabry-Pérot microcavity with deep Si/SiO 2 Bragg reflectors. Carriers are laterally confined in the cavity region by employing deep-etched trenches. The refractive index of the cavity is varied by using the free-carrier dispersion effect produced by a p-i-n diode. The device has been designed and analyzed using electrical and optical simulations. Our calculations predict, for a 20-m-long device, a modulation depth of around 80% and a transmittance of 86% at an operating wavelength of 1.55 m by using an electrical power under dc conditions on the order of 25 W.

Electrooptic modulation of silicon-on-insulator submicrometer-size waveguide devices

“…The values of and for a voltage pulse with V V and V V are 1.11 and 0.18 ns, respectively. As pointed out in our previous work [7], carrier diffusion and carrier depletion due to the reverse electric field are the limiting mechanisms for carrier injection and carrier removal , respectively. Due to the small volume of the guiding intrinsic region, the calculated switching time ( 1.29 ns) is one order of magnitude smaller than those reported for larger rib structures [7], [18].…”

“…An increase in the device temperature for a p-i-n/rib structure occurs during the transition from the ON state to the OFF state, due to a significant increase of the transient reverse current [7]. The maximum device temperature in the studied device is shown in Fig.…”

“…The transmission near the resonance wavelength of an optical cavity is highly sensitive to small index changes, making it ideal for intensity modulation in a short length [7]. Thus, an immediate application of the studied configuration is a straight waveguide intensity modulator based on a microcavity [6] (see Fig.…”

“…Active waveguide devices (modulators and switches), however, have been proposed only on large micrometer-size SOI waveguides [7], [8]. Very little work has been reported on high-index-contrast (high lateral optical confinement) waveguide active devices despite their high demand to manipulate light beams for information processing (e.g., coding-decoding, routing, multiplexing, timing, logic operations, etc.)…”

Analysis of a Compact Modulator Incorporating a Hybrid Silicon/Electro-Optic Polymer Waveguide

“…Resonant cavity devices, such as Fabry-Perot or microring resonators, can generally have smaller device dimensions, but it is challenging to achieve large modulation depths required for the optical communication applications. Barrios et al fabricated and tested a silicon Fabry-Perot resonant cavity modulator with a total device length of 19 µm [5], [6]. This modulator used freecarrier injection and thermal effects to achieve the phase change in the resonant cavity region.…”