Bend radius

About: Bend radius is a research topic. Over the lifetime, 3303 publications have been published within this topic receiving 35415 citations. The topic is also known as: minimum bend radius.

Structure Tuned, High Transmission 180 $^{\circ}$ Waveguide Bend in 2-D Planar Photonic Crystal

Abstract: We present a high transmission, small bending radius, 180° waveguide bend based on triangular lattice air holes two-dimensional (2-D) planar photonic crystal. The desired high transmission is achieved by altering the waveguide structure at the bending region. Drop hole defects are introduced at the bending region to guide the incoming electromagnetic wave. Simulation results based on the 2-D finite difference time domain method show that normalized transmission as high as 99.4% is achieved at 1550 nm optical wavelength and it is >94% for nearly the entire optical C-band. In addition, the small bending radius enhances the suitability of our design to be used in ultra-compact photonic integrated circuits.

A Heterogeneous Silicon on Lithium Niobate Modulator for Ultra-Compact and High-Performance Photonic Integrated Circuits

Abstract: We propose a heterogeneous silicon on lithium niobate (Si-LN) modulator which improves the compactness and modulating performance of large-scale photonic integrated circuits. Two types of configurations are employed on the Si-LN wafer for ultra-compact light-routing waveguides and high-performance light-modulating waveguides, respectively. The low loss taper transfers the optical modes between the two waveguides. In the heterogeneous Si-LN modulator, LN etching is nonessential and thus device processes are supported on a robust wafer. Our design analyzes the influence of the LN thickness on the performance. According to theoretical analysis and numerical simulation, the modulator supports a bend radius of 10 μm and edge-to-edge waveguide separation of 0.7 μm with respect to ∼1 cm beat length. When thickness of LN is 700 nm, the modulation efficiency reaches 1.76 V⋅cm and the bandwidth exceeds 350 GHz. This modulator is potentially suitable for ultra-compact, large-scale, high efficiency, and large bandwidth photonic integrated circuits (PICs).

Minimizing bend loss by removing material inside the caustic in bent single-mode fibers

Abstract: By removing the cladding on the outside of a bent single-mode optical fiber and exposing a surface at a radius smaller than that of the radiation caustic, the leaky nature of the propagating mode is almost suppressed, and bend loss is effectively eliminated. The practical realization of this effect is described, and a loop with a bend radius of 0.50 mm on standard telecommunications fiber is demonstrated with negligible loss.

Effect of inertial lift on a spherical particle suspended in flow through a curved duct

Abstract: We develop a model of the forces on a spherical particle suspended in flow through a curved duct under the assumption that the particle Reynolds number is small. This extends an asymptotic model of inertial lift force previously developed to study inertial migration in straight ducts. Of particular interest is the existence and location of stable equilibria within the cross-sectional plane towards which particles migrates. The Navier-Stokes equations determine the hydrodynamic forces acting on a particle. A leading order model of the forces within the cross-sectional plane is obtained through the use of a rotating coordinate system and a perturbation expansion in the particle Reynolds number of the disturbance flow. We predict the behaviour of neutrally buoyant particles at low flow rates and examine the variation in focusing position with respect to particle size and bend radius, independent of the flow rate. In this regime, the lateral focusing position of particles approximately collapses with respect to a dimensionless parameter dependent on three length scales, specifically the particle radius, duct height, and duct bend radius. Additionally, a trapezoidal shaped cross-section is considered in order to demonstrate how changes in the cross-section design influence the dynamics of particles.

Optical fiber cable leading-out device

Abstract: PURPOSE:To prevent an optical fiber cable from being damaged by a torsion of the cable and a difference of a bend radius, by controlling a roller driving mechanism so that a tension of the optical fiber cable becomes within an allowable tension range in accordance with a detecting signal of a tension detector CONSTITUTION:A tension detector 16 is installed to a machine body frame 6 in the vicinity of the first leading-out roller 7 To the tension detector 16, a controller 20 for controlling a roller driving mechanism 9 is installed so that a tension of an optical fiber cable 2 becomes within an allowable tension range in accordance with a detecting signal When the tension of the optical fiber cable 2 becomes large in the course of a leading-out work, a dancer arm 18 is turned counterclockwise, and when said tension becomes small, said arm is turned clockwise, a turning shaft 17 is turned, the controller 20 is driven to turn and its resistance value is varied, and the tension of the optical fiber cable 2 is controlled so as to become with the allowable tension range