The need for computational resources has grown significantly in today's information society, and the density of conventional integrated circuit transistors is getting close to its physical limit.

On the other hand, optoelectronic and photonic devices and circuits based on silicon-on-insulator (SOI) are appealing because they can be fabricated using the complementary metal-oxide-semiconductor (CMOS) process and have the potential for monolithic integration on CMOS chips.

The SOI waveguide crossing is a crucial device unit to create a variety of implementation schemes, such as shaped taper waveguide crossing, multimode interferometers, and photonic crystal waveguide crossing.

All-optical Boolean functions are essential elements for information optical processing because they efficiently overcome the fundamental restrictions of their electronic equivalents, particularly the constrained data transfer speed, and bandwidth.

In this research, Amer Kotb from Changchun Institute of Optics, Fine Mechanics and Physics (CIOMP) of the Chinese Academy of Sciences (CAS) in China and his co-author, Kyriakos Zoiros, from the Democritus University of Thrace in Greece have proposed compact 2x2 silicon-on-silica waveguides to realize seven basic Boolean logic functions, i.e. XOR, AND, OR, NOT, NOR, XNOR, and NAND, operated at 1.55 μm telecommunications wavelength.

Through comparison of the outcomes published in Photonics with other reported designs, it is shown that the proposed design exhibits higher contrast ratios at a high speed of 120 Gb/s.

Amer Kotb     amer@ciomp.ac.cn