Fiber Optic Tutorials

This is a continuation from the previous tutorial - metal-coated fibers.   1. Transverse Modes in Optical Resonators Laser cavities differ in several significant ways from the closed microwave cavities that are commonly treated in electromagnetic theory tutorial. Optical resonators first of all usually have open sides, and hence always have diffraction losses because of energy leaking out the sides of the resonator to infinity. Optical resonators are also usually described in scalar or quasi plane-wave terms, with emphasis on the diffraction effects at apertures and mirror edges, rather than in vector terms with emphasis on matching boundary conditions. The...

This is a continuation from the previous tutorial - acousto-optic devices and applications.   1. Introduction An optical fiber has to be defended by some protective coating from mechanical damage during handling and from environmental factors during its use. In many cases, a polymer coating is appropriate for enough protection. However, there are a number of special applications of optical fibers in which ordinary polymer-coated fibers cannot be used. These applications can be divided into several groups: Increased reliability (hermeticity of the coating is important) High vacuum (when outgassing from the coating is undesirable) Possibility of soldering (embedded fibers, pigtails,...

This is a continuation from the previous tutorial - nonlinear compensation for digital coherent transmission.   1. Introduction When an acoustic wave propagates in an optically transparent medium, it produces a periodic modulation of the index of refraction via the elasto-optical effect. This provides a moving phase grating which may diffract portions of an incident light into one or more directions. This phenomenon, known as the acousto-optic (AO) diffraction, has led to a variety of optical devices that perform spatial, temporal, and spectral modulations of light. These devices have been used in optical systems for light-beam control and signal-processing applications....

This is a continuation from the previous tutorial - laser oscillation dynamics and oscillation threshold.   1. Introduction The degree to which fiber impairments are compensated determines the transmission capacity of fiber-optic transmission systems. Dispersion-compensating fiber (DCF) is commonly used to compensate chromatic dispersion.Wavelength-division multiplexing (WDM) systems suffer from both intra- and interchannel nonlinearities such as cross-phase modulation (XPM) and four-wave mixing (FWM). These effects can be suppressed using dispersion management. Compensation of nonlinear impairments in fiber has become the next logical step in increasing the capacity of WDM systems. A few optical nonlinearity compensation schemes have been demonstrated such...

This is a continuation from the previous tutorial - hermetic optical fibers - carbon-coated fibers.   In this tutorial we discuss a number of additional topics related to the elementary properties of laser oscillation. We consider first the oscillation build-up time with which coherent oscillation develops from noise in a laser cavity. From this we develop a set of simple coupled rate equations which link cavity photons to laser atoms, and laser atoms to cavity photons. Using these equations we explore further the laser oscillation buildup and the remarkable threshold properties characteristic of the laser oscillator. We then examine briefly some...