Fiber Optic Tutorials
Polarization and Nonlinear Impairments in Fiber Communication Systems
This is a continuation from the previous tutorial - nonlinear optical pulse propagation. 1. Introduction Polarization is a property of waves that can oscillate with more than one orientation. Electromagnetic waves such as light exhibit polarization. Although polarization can be used as another dimension to carry information, in practice, this feature is not utilized in direct-detection optical communication systems due to the difficulties of polarization demultiplexing in the optical domain. It was only until recently, with the advent of digital coherent detection, polarization-division multiplexing (PDM), which transmits signals on two orthogonal states of polarization (SOPs) at an identical wavelength,...
Nonlinear Optical Pulse Propagation
This is a continuation from the previous tutorial - silica nanofibers and subwavelength-diameter fibers. All the propagation phenomena described in the linear pulse propagation tutorial are linear propagation effects, produced by the linear response of the propagating systems. In this tutorial we will give a brief survey of a few of the most important nonlinear propagation phenomena that occur with optical pulses. These effects include in particular: gain saturation in pulsed amplifiers (which is a relatively weak form of nonlinearity); optical pulse propagation through nonlinear dispersive systems in general; and the especially interesting topic of nonlinear pulse propagation in optical fibers,...
Silica Nanofibers and Subwavelength-Diameter Fibers
This is a continuation from the previous tutorial - introduction to binary optics. 1. Nanofiber at a glance Air-clad silica (SiO2) nanofibers, named for their submicrometer diameters, have a large core-cladding index contrast for efficient optical confinement. For single-mode operation, these fibers are usually thinner than the wavelength of the light they carry and are, therefore, also called subwavelength-diameter fibers. The small diameter of a nanofiber and the large core-cladding index contrast yield a number of interesting optical properties such as tight optical confinement, large evanescent fields, strong field enhancement, and large waveguide dispersions. The nanofibers are fabricated by...
Introduction to Binary Optics
This is a continuation from the previous tutorial - spectrally efficient multiplexing - OFDM. 1. Introduction Binary optics is a surface-relief optics technology based on VLSI fabrication techniques (primarily photolithography and etching), with the ‘‘binary’’ in the name referring to the binary coding scheme used in creating the photolithographic masks. The technology allows the creation of new, unconventional optical elements and provides greater design freedom and new materials choices for conventional elements. This capability allows designers to create innovative components that can solve problems in optical sensors, optical communications, and optical processors. Over the past decade, the technology has...
Spectrally Efficient Multiplexing - OFDM
This is a continuation from the previous tutorial - linear pulse propagation. Single-carrier modulation (SCM) has been the de facto modulation choice and has long been implemented in commercialized products for both long- and short-reach optical fiber communications. The SCM gains its popularity due to low hardware complexity for relatively low-speed (10 Gb/s or less) communication systems. In the recent decade, multicarrier modulation (MCM), which has higher spectral efficiency (SE) than the conventional SCM, has been argued as a promising alternative to satisfy the exponential growth of the Internet traffic. Several schemes that utilize MCM have been demonstrated since...