In this paper, the response time of all-optical AND logic gate using the triangular photonic crystal lattice is investigated. The proposed logic gate consists of a photonic crystal nano-resonator formed by changing the size of the dielectric rods. The structure benefits the interference effect mechanism. The contrast ratio of the photonic crystal AND logic gate is obtained as 6 dB. In addition to simplicity, the designed nano-resonator increases the bit rate of logic gate. The delay time and footprint of logic gate are respectively 0.32 ps and 146 μm². The proposed photonic crystal AND logic gate can operate at a bit rate of 3.12 Tbit/s

In this paper, we have proposed a metal-insulator-metal (MIM) pressure sensor which consists of two plasmonic waveguides and a double square ring resonator. The two square rings are connected via a rectangular patch located between the two of them. The surface plasmon polaritons (SPPs) can be transferred from a square ring to the other through this patch. The finite-difference time-domain method (FDTD) has been used to simulate the device. Applying a pressure on the structure, it deforms, and a red shift of 103 nm in the resonance wavelength has been calculated. The deformation is linearly proportional to the wavelength shift in a wide range of wavelength. The proposed optical plasmonic pressure sensor has a sensitivity of 16.5 nm/MPa which makes it very suitable for using in biological and biomedical engineering.

The propagation loss of a fiber can be increased by coupling core mode and surface mode which will deteriorate the performance of photonic bandgap fiber (PBGF). In this paper, we presented an aircore PBGF for gas sensing applications. By designing Λ = 2.63 μm, d = 0.95 Λ, and Rcore= 1.13 Λ, where Λ is the distance between the adjacent air holes, the fiber was single-mode, no surface mode was supported with fiber, and more than 90% of the optical power was confined in the core. Furthermore, with optimizing the fiber structural parameters, at wavelength of l = 1.55 μm that is in acetylene gas absorption line, significant relative sensitivity of 92.5%, and acceptable confinement loss of 0.09 dB/m, were simultaneously achieved.

In this paper, we present a micro-displacement sensor formed by the fixed and movable photonic crystal slabs. In this sensor, a waveguide was created by changing the radius of holes rather than removing them. At a proper operating wavelength, the structure could be used as the micro-displacement sensor. The results revealed that the micro-displacement sensor had a sensitivity of 3.6 μm-1, the Q-factor was nearly 180, and the sensing range was 0.0 μm-0.5 μm. The properties of the micro-displacement sensor are also analyzed theoretically and verified using the finite-difference time-domain (FDTD) method carried out using the software (Rsoft).

In this paper, we design and characterize a novel small size four-channel biosensor based on the two-dimensional photonic crystal with introducing waveguides and nano-cavities in the hexagonal lattice of air pores in the silicon slab. By removing a group of air pores, waveguides are achieved, and nano-cavities are shaped by modifying the radius of air pores. Highly parallel operation of this biosensor due to the special architecture is the capability of the designed structure. The biomaterials which are suspended in a liquid medium inside nano-cavities cause effective refractive index changes which lead to the resonant wavelength shift in the output terminal. According to results, with increasing the refractive index of nano-cavities, resonant wavelengths shifts to longer values. For biochemical sensing like DNA molecule and protein and for the refractive index detection, this novel designed biosensor can be utilized.

An index guiding photonic crystal fiber used in gas sensing applications is presented. The dependency of the confinement loss and relative sensitivity on the fiber parameters and wavelength is numerically investigated by using the full-vectorial finite element method (FEM). The simulations showed that the gas sensing sensitivity increased with an increase in the core diameter and a decrease in the distance between centers of two adjacent holes. Increasing the hole size of two outer cladding rings, this structure simultaneously showed up to 10% improved sensitivity, and the confinement loss reached 6×10-4 times less than that of the prior sensor at the wavelength of 1.5 μm. This proved the ability of this fiber used in gas and chemicals sensing applications.

The authors present a new design of high resolution and wide dynamic range photonic crystal pressure sensor. This sensor is based on two-dimensional photonic crystal with square array of silicon rods surrounded by air. The sensor consists of a photonic crystal waveguide which is coupled to a photonic crystal nanocavity. The waveguide is configured by removing one row of Si rods and nanocavity is formed by modifying the radius of one Si rod. The sensor is designed for 1300nm–1400nm wavelengths. Simulation results show that resonant wavelength of nanocavity is linearly shifted to larger wavelengths by increasing the pressure. The designed sensor has a linear behavior between 0.1GPa to 10GPa of applied pressure and 8nm/GPa of pressure sensitivity.