China
Africa
Explore chapters and articles related to this topic
(3) Processes
Published in Peter E. Powers, Joseph W. Haus, Fundamentals of Nonlinear Optics, 2017
Peter E. Powers, Joseph W. Haus
Nonlinear phase shifts may be appreciable for pulsed lasers focused to tight spots sizes. However, another way to obtain appreciable effects is by utilizing long interaction lengths. In fiber-optic-based devices, interaction lengths of 100−1000 m are not uncommon. The intensity required to satisfy Equation 8.109 (using a 100 m fiber) is ∼30 MW/cm2, which is easily attainable with a pulsed laser in a fiber. For example, many fiber lasers operate with pulse energies on the order of 1 μJ and 10 ns pulse durations. Fiber sizes vary, but a typical mode-field diameter is 10 μm. Under these conditions, the intensity is roughly 130 MW/cm2 so that nonlinear phase shifts are important for fiber lengths >100 m. For situations where the fiber length or IP are less than in this example, the nonlinear contribution to κ is negligible and device performance is dominated by Δk. For fiber devices, Δk must include the fiber's waveguide dispersion.
Semiconductor Optical Fibers
Published in Inamuddin, Mohd Imran Ahamed, Rajender Boddula, Tariq Altalhi, Optical Properties and Applications of Semiconductors, 2023
Lele Zang, Qixun Xia, Zhijun Du, Nanasaheb M. Shinde
Mode field diameter (MFD) is used to characterize the distribution state of fundamental mode light in the core region of the single-mode fiber. The light intensity of the fundamental mode is the highest at the axial line in the core region and gradually decreases with the increase of the distance away from the axial line. The MFD is generally defined as the maximum distance between two points in each point where the light intensity is reduced to 1/(e^2) of the maximum light intensity at the axis line. The diameter of the mode field is related to the wavelength used. The diameter of the mode field increases with the increase of the wavelength.
Optical Fiber
Published in Kenichi Iga, Yasuo Kokubun, Encyclopedic Handbook of Integrated Optics, 2018
The structure of optical fiber for telecommunication use is standardized by ITU (formerly CCITT) as shown in Figure 2. The diameter of the glass part (cladding) is 125 μm. The core diameter is determined so that the mode field diameter (see below) is equal to the standardized number, typically 8 to 10 μm.
Modelling, design and optimization of compact taper and gratings for mode coupling to SOI waveguides at C-band
Published in Journal of Modern Optics, 2020
Venkatesha Muniswamy, Narayan Krishnaswamy
The major problem in nanoscale optical components is the coupling of light from optical fibre to the nanoscale optical waveguides [6–10]. In simulation a single-mode fibre, having dimensions of 1 µm core radius and 100 µm cladding diameter, is chosen for illumination of light on the input section of GC. The RI of the core and cladding of the fibre considered are 1.44 and 1.43, respectively. The fibre mode profile is shown in Figure 5. The losses in the fibre are ∼0 dB/cm. The effective index of the fibre is 1.4328 at a wavelength of 1550 nm. The mode field diameter (MFD) is measured at 1/e times the maximum intensity of normalized field intensity. The MFD of the fibre with the help of normalized electric field, shown in Figure 5, is ∼20 µm.