Strained Silicon Photonics

Abstract

A review of recent progress in the field of strained silicon photonics is presented. The application of strain to waveguide and photonic crystal structures can be used to alter the linear and nonlinear optical properties of these devices. Here, methods for the fabrication of strained devices are summarized and recent examples of linear and nonlinear optical devices are discussed. Furthermore, the relation between strain and the enhancement of the second order nonlinear susceptibility is investigated, which may enable the construction of optically active photonic devices made of silicon.

Bond orbital description of the strain-induced second-order optical susceptibility in silicon

“…This is in line with the claims that χ (2) should be proportional to strain gradients and not to strain itself, as it has been suggested in many publications in the past years [6][7][8][9]22]; more importantly it gives the exact value of the weight of each strain gradient direction for the desired χ (2) component. Other known experimental fact of strained silicon is that χ (2) has a linear relationship with the initial stress σ 0 in the straining layer [10,12,35].…”

“…In fact, over the last few years Pockels electro-optic modulation [4][5][6][7][8] and SHG [9,10] have been claimed to be demonstrated in devices where the silicon active region is strained by a stress overlayer, usually made of SiN. Motivated by its enormous potential, the interest in strained silicon photonics devices has been growing in the past years.…”

All‐Around SiN Stressor for High and Homogeneous Tensile Strain in Germanium Microdisk Cavities

“…More recently, strain engineering has become a key element for silicon photonics. [ 1 ] Applying strain can modify the electronic band structures of silicon-based materials as well as the lattice symmetry properties. The centrosymmetry of the silicon lattice can be broken by depositing a stressor layer on top of silicon waveguides thus leading to strain gradient.…”

Analysis of the Pockels effect in ferroelectric barium titanate thin films on Si(0 0 1)

“…Results are summarized in Table 1 for comparison with previous works, for example $2 pm/V for strained Si, $30 pm/V for LiNbO 3 on Si, and 148 pm/V for BTO/Si [1,16,17]. By comparing the effective Pockels coefficient for the mixed films, we see that the strongest response is observed for the e-beam Ti sample.…”