Applications Of Optical Phase Conjugation Research Articles

On Four-Wave Mixing Suppression in Dispersion-Managed Fiber-Optic OFDM Systems With an Optical Phase Conjugation Module

Coherent optical orthogonal frequency-division multiplexed (OFDM) systems with uniform chromatic dispersion can efficaciously combat both fiber dispersion by utilizing the properties of the cyclic prefix and four-wave mixing (FWM) among the individual subcarriers via the phased-array effect in dispersive fiber links. Such excellent performance, however, often implies appreciable sacrifices in data rate, since a long cyclic prefix is required to compensate for the dispersion accumulated at the receiver. The spectral efficiency of such OFDM systems may be substantially improved by dispersion management. Dispersion-compensating fibers placed periodically along the transmission line can significantly shorten the channel memory thereby allowing a reduction in the cyclic prefix overhead. However, the FWM tolerance of such dispersion-managed (DM) links may suffer considerably. In this work, the application of optical phase conjugation (OPC) to DM OFDM systems is investigated. Several systems set-ups are considered, and the degrees of inter-subcarrier FWM suppression are estimated analytically for arbitrary dispersion map parameters. A comparison is also made against links with uniform chromatic dispersion. Despite their inherently inferior FWM tolerance properties, DM OFDM systems can be made quite competitive with the application of OPC.

Analysis of Four-Wave Mixing Suppression in Fiber-Optic OFDM Transmission Systems With an Optical Phase Conjugation Module

Coherent optical orthogonal frequency-division multiplexed (OFDM) systems must be carefully designed to minimize the detrimental impact of fiber nonlinearity manifested through four-wave mixing (FWM). Because of the small subcarrier spacing associated with OFDM, a significant fraction of FWM processes is well matched, resulting in a rapid buildup of FWM light with propagation distance. In this paper, we consider optical phase conjugation (OPC) as an approach to suppress such well-matched FWM processes. An analytical formula accurately predicting the degree of suppression is derived and discussed. It is shown that when combined with the methods previously proposed in the literature, the application of OPC can dramatically reduce the overall FWM power accumulated within the link for a wide range of crucial design parameters.

Nonlinearity Compensation in a Fiber-Optic Link by Optical Phase Conjugation

This article is intended as a guide to the techniques for nonlinearity compensation in a fiber-optic communication link based on optical phase conjugation. In the first part, the basics of the phase conjugation process are illustrated from both a mathematical and physical point of view. Then, the more commonly used devices for optical phase conjugation are described, with particular attention to the devices based on periodically poled lithium niobate waveguides. Subsequently, the applications of optical phase conjugation to the nonlinearity compensation of amplitude-modulated and phase-modulated signals are analyzed.

Generation of optical phase-conjugate waves and compensation for pulse shape distortion in a single-mode fiber

The generation of optical phase-conjugate waves and the application of optical phase conjugation (OPC) to optical communication systems is described. The method of pulse shape distortion compensation by OPC is outlined including distortion due to both fiber dispersion and the optical Kerr effect. The generation of a forward-going phase-conjugate wave in a third-order nonlinear medium is discussed and that by a nondegenerate forward four-wave mixing in a zero-dispersion single-mode fiber (SMF) is investigated. Suppressing the stimulated Brillouin scattering (SBS) of a pump wave in the fiber prevents saturation of the generation efficiency of the phase-conjugate wave even when the pump power exceeds the SBS threshold. In transmission experiments through a 200-km standard SMF with a 16-Gb/s intensity-modulated signal and a 5-Gb/s continuous-phase FSK (CPFSK) modulated signal, it is shown the applicability of OPC is modulation independent and that OPC effectively compensates for both chromatic dispersion and the optical Kerr effect.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Applications of Optical Phase Conjugation

Applications of Optical Phase Conjugation

Optical Phase Conjugation

The time-reversal of light waves is discussed. Two of the most widely used methods of phase conjugation of light waves, stimulated Brillouin scattering and four-wave mixing, are described. The physical bases of both methods are shown. Two possible applications of optical phase conjugation, the production of highly directed laser beams and the self-targeting of radiation, are discussed.

Application of optical phase conjugation to plasma diagnostics (invited)

Several possibilities for plasma diagnostics provided by optical phase conjugation and, in particular, self-pumped phase conjugation in barium titanate (BaTiO3) are discussed. These include placing a plasma within a dye laser cavity equipped with a phase conjugate mirror for intracavity absorption measurements, time differential refractometry with high spatial resolution, and simplified real-time holographic interferometry. The principles of phase conjugation with particular reference to photorefractive media and the special advantages of self-pumped phase conjugation are reviewed prior to the discussion of the applications. Distinctions are made in the applications between those for which photorefractive conjugators are essential and those for which they only offer experimental simplification relative to other types of phase conjugators.