Functional all-optical logic gates for true time-domain signal processing in nonlinear photonic crystal waveguides

Abstract

We present a conceptual study on the realization of functional and easily scalable all-optical NOT, AND and NAND logic gates using bandgap solitons in coupled photonic crystal waveguides. The underlying structure consists of a planar air-hole type photonic crystal with a hexagonal lattice of air holes in crystalline silicon (c-Si) as the nonlinear background material. The remaining logical operations can be performed using combinations of these three logic gates. A unique feature of the proposed working scheme is that it operates in the true time-domain, enabling temporal solitons to maintain a stable pulse envelope during each logical operation. Hence, multiple concatenated all-optical logic gates can be easily realized, paving the way to multiple-input all-optical logic gates for ultrafast full-optical digital signal processing. In the suggested setup, there is no need to amplify the output signal after each operation, which can be directly used as a new input signal for another logical operation. The feasibility and efficiency of the proposed logic gates as well as their scalability is demonstrated using our original rigorous theoretical formalism together with full-wave computational electromagnetics.

Realization of optical logic gates using on-chip diffractive optical neural networks

“…no. Device architecture Gate Operation wavelength Dimensions Bit rate Contrast ratio (dB) Operation bandwidth 12 Si wire gate AND, NOR, XNOR 1.55 µm 3 µm × 3 µm 20Gbps > 9 30 nm 19 L-shaped Optical slot nano-antenna (AND, OR) or (NOT, NOR, NAND) depending on the orientation of the L-shaped antenna 800 nm 300 nm × 300 nm – > 13.27 230 nm 13 Mach–Zehnder interferometer switch All seven logic gates but using different cascading schemes 1.55 µm 50 µm × 21 µm 25Gbps – – 2 Coupled nonlinear photonic crystal waveguides AND, NOT – – – 20 – 14 Two-dimensional photonic crystal All seven logic gates but using different number of basic gates 2.5793 µm (116.31THz) < 150 µm × 45 µm – > 9.54 – 3 Micro-resonator AND 1.55 µm 1.5 mm × 1.5 mm 5kbps 11 <...…”

“…Optical logic gates are crucial building blocks for all-optical computing and they enable many applications like ultrahigh-speed information processing and all-optical networks. There are two major approaches toward all optical logic gates; one is based on the nonlinear optical effects 2 – 10 , especially the third-order nonlinear susceptibility, while another approach is based on the linear optical effects 11 – 19 such as multi-beam interference 12 – 18 . However, the inherent instability of the interference-type optical logic circuits (including linear and nonlinear interference) hindered their application.…”

An Introduction to Nonlinear Integrated Photonics: Structures and Devices

“…If the intensity of the incident field is subsequently lowered, the field inside the cavity tends to remain large because the absorption of the material system has again been reduced. However, even if single bistable switches have already been demonstrated on different platforms, it is worth noting that the next big challenge is realization of a complex system where several bistable switches are connected in tandem and in parallel [ 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 ].…”

Realization of optical logic gates using on-chip diffractive optical neural networks

“…Optical logic gates are crucial building blocks for all-optical computing and they enable many applications like ultrahigh-speed information processing and all-optical networks. There are two major approaches toward all optical logic gates; one is based on the nonlinear optical effects [2][3][4][5][6][7][8][9][10], especially the thirdorder nonlinear susceptibility, while another approach is based on the linear optical effects [11][12][13][14][15][16][17][18][19] such as multi-beam interference [12][13][14][15][16][17][18]. However, the inherent instability of the interference-type optical logic circuits (including linear and nonlinear interference) hindered their application.…”