Use of Reconfigurable IM Regions to Suppress Propagation and Polarization Dependent Losses in a MMI Switch

With this work, use of reconfigurable index modulated (IM) regions to accelerate the performance of a multimode interference (MMI) based photonic switch is presented. Appropriate dimension for such regions are defined to suppress the transition losses and to optimize the area coverage. It has been noticed that by reconfiguring the IM regions, perfect switching for test wavelengths of 1.3μ m and 1.55μ m with low insertion loss (I.L.) levels, ≤ 1.2dB and excess loss (E.L.) levels, ≤ 0.17dB can be achieved with vacillation of extremely low polarization dependent losses (PDLs), which are ≤ 0.15dB. For either case of input test wavelengths, generated crosstalk (CT) levels are found better than -21.8dB for TE and -20.2dB for TM polarization state

Substrate Current Evaluation for Lightly and Heavily Doped MOSFETs at 45 Nm Process Using Physical Models

Substrate noise is a major integration issue in mixed signal circuits; particularly at radio frequency (RF) it becomes a key issue. In deep sub micron MOSFETs hot carrier effect induces device degradation. The impact ionization phenomenon is one of the main hot carrier effects. The paper covers the process and device level simulation of MOSFETs by TCAD and the substrate current comparison in lightly and heavily doped MOS. PMOS and NMOS devices are virtually fabricated with the help of ATHENA process simulator. The modeled devices include the hot carrier effects. The MOS devices are implemented on lightly and heavily doped substrates and substrate current is evaluated and compared with the help of ATLAS device simulator. Substrate current is better in lightly doped substrate than in heavily doped one. Drain current is also better in lightly doped than heavily doped substrates. Silvaco TCAD Tool is used for Virtual fabrication and simulation. ATHENA process simulator is used for virtual fabrication and ATLAS device simulator is used for device characterization

Ultrabroad supercontinuum generation in tellurite equiangular spiral photonic crystal fiber

Simulations are presented of a very broad and flat supercontinuum (SC) in both the normal and anomalous group velocity dispersion regimes of the same equiangular spiral photonic crystal fiber at low pumping powers. For a pump wavelength at 1557 nm and average pump power of 11.2 mW, we obtained a bandwidth >3 μm (970 nm–4100 nm) at 40 dB below the peak spectral power with fiber dispersion 2.1 ps/km nm at 1557 nm. In the same fiber, at pump wavelength 1930 nm and average pump power of 12 mW the SC bandwidth was more than two octaves (1300 nm–3700 nm) and dispersion was 1.3 ps/km nm at 1930 nm. This demonstrates the potential use of the fiber for multi-wavelength pumping with commercially available sources at fairly low power

A versatile all-optical parity-time signal processing device using a Bragg grating induced using positive and negative Kerr-nonlinearity

The properties of gratings with Kerr nonlinearity and PT symmetry are investigated in this paper. The impact of the gain and loss saturation on the response of the grating is analysed for different input intensities and gain/loss parameters. Potential applications of these gratings as switches, logic gates and amplifiers are also shown

Electro-thermal modelling for plasmonic structures in the TLM Method

This paper presents a coupled electromagnetic-thermal model for modelling temperature evolution in nano-size plasmonic heat sources. Both electromagnetic and thermal models are based on the Transmission Line Modelling (TLM) method and are coupled through a nonlinear and dispersive plasma material model. The stability and accuracy of the coupled EM-thermal model is analysed in the context of a nano-tip plasmonic heat source example

Theory and numerical modelling of parity-time symmetric structures in photonics: introduction and grating structures in one dimension

A class of structures based on PT PT-symmetric Bragg gratings in the presence of both gain and loss is studied. The basic concepts and properties of parity and time reversal in one-dimensional structures that possess idealised material properties are given. The impact of realistic material properties on the behaviour of these devices is then investigated. Further extension to include material non-linearity is used to study an innovative all-optical memory device