https://engineering.purdue.edu/~fsoptics/articles/Ultrafast_optical_pulse_shaping_tutorial-Weiner.pdf

Ultrafast optical pulse shaping: A tutorial review

Progress in optical networking has stimulated interest in optical performance monitoring (OPM), particularly regarding signal quality measures such as optical signal-to-noise ratio (SNR), Q-factor, and dispersion. These advanced monitoring methods have the potential to extend fault management and quality-of-service (QoS) monitoring into the optical domain. This paper reviews OPM applications and techniques, while examining the role of OPM as an enabling technology for advances in high-speed and optically switched networks.

Optical performance monitoring

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The transmission of a pair of phase-conjugated beams is shown to mitigate nonlinear distortion during optical fibre communication, allowing a 400 Gbit s−1 superchannel to be sent over 12,800 km of optical fibre.

Phase-conjugated twin waves for communication beyond the Kerr nonlinearity limit

An intelligent video/audio observation and identification database system may define a security zone or group of zones. The system may identify vehicles and individuals entering or exiting the zone through image recognition of the vehicle or individual as compared to prerecorded information stored in a database. The system may alert security personnel as to warrants or other information discovered pertaining to the recognized vehicle or individual resulting from a database search. The system may compare images of a suspect vehicle, such as an undercarriage image, to standard vehicle images stored in the database and alert security personnel as to potential vehicle overloading or foreign objects detected, such as potential bombs. The system may track individuals or vehicles within a zone or between zones. The system may further learn the standard times and locations of vehicles or individuals tracked by the system and alert security personnel upon deviation from standard activity.

Intelligent observation and identification database system

The invention provides an optical wavelength multiplex transmission method wherein a band in the proximity of a zero dispersion wavelength of an optical fiber is used and optical signals are disposed at efficient channel spacings taking an influence of the band, the wavelength dispersion and the four wave mixing into consideration to realize an optical communication system of an increased capacity which is not influenced by crosstalk by FWM. When optical signals of a plurality of channels having different wavelengths are to be multiplexed and transmitted using an optical fiber, a four wave mixing suppressing guard band of a predetermined bandwidth including the zero-dispersion wavelength λθ of the optical fiber is set, and signal light waves of the plurality of channels to be multiplexed are arranged on one of the shorter wavelength side and the longer wavelength side outside the guard band.

Optical wavelength multiplex transmission method and optical dispersion compensation method

The invention provides a technique for optimizing transmission conditions to achieve large-capacity transmission, and also provides peripheral techniques for the practical implementation of optical multiplexing that makes large-capacity transmission possible. A transmission characteristic is measured in a transmission characteristic measuring section (53), and control of signal light wavelength in a tunable light source (44), control of the amount of prechirping, control of the amount of dispersion compensation, and/or control of optical power are performed to achieve the best transmission characteristic. Wavelength dispersion is deliberately introduced by a dispersion compensator, to reduce nonlinear effects. A tunable laser is used to optimize signal light wavelength for each optical amplification repeater section. Peripheral techniques, such as drift compensation, clock extraction, optical signal channel identification, clock phase stabilization, etc., are provided for the implementation of optical multiplexing.

Optical transmission system, optical multiplexing transmission system, and related peripheral techniques

The invention provides a technique for optimizing transmission conditions to achieve large-capacity transmission, and also provides peripheral techniques for the practical implementation of optical multiplexing that makes large-capacity transmission possible. A transmission characteristic is measured in a transmission characteristic measuring section, and control of signal light wavelength in a tunable light source, control of the amount of prechirping, control of the amount of dispersion compensation, and/or control of optical power are performed to achieve the best transmission characteristic. Wavelength dispersion is deliberately introduced by a dispersion compensator, to reduce nonlinear effects. A tunable laser is used to optimize signal light wavelength for each optical amplification repeater section. Peripheral techniques, such as drift compensation, clock extraction, optical signal channel identification, clock phase stabilization, etc., are provided for the implementation of optical multiplexing.

Optimized optical transmission system for high capacity transmission

Pulse shape distortion due to chromatic dispersion and self-phase modulation in a single-mode fiber was effectively compensated for by using an optical phase-conjugate wave generated by nondegenerate forward four-wave mixing in a zero-dispersion single-mode fiber. Using optical phase conjugation at the midpoint of a 100-km standard single-mode fiber compensates for the distortion of 10-Gb/s intensity-modulated NRZ pulse at an input power level exceeding +10 dBm with a resultant power penalty of less than 1.2 dB. >

Compensation of pulse shape distortion due to chromatic dispersion and Kerr effect by optical phase conjugation

A method and apparatus for optimizing dispersion in an optical fiber transmission line. The method and apparatus (a) determine an optimum amount of total dispersion of an optical transmission line corresponding to a power level of an optical signal transmitted through the optical transmission line; (b) control dispersion of the optical transmission line so that the total dispersion up to a specific point along the optical transmission line becomes approximately zero; and (c) add dispersion to the optical transmission line downstream of the specific point, to obtain the determined optimum amount of total dispersion. The control of dispersion in (b), above, can be performed in several different manners. For example, the control of dispersion can include (i) detecting the intensity of a specific frequency component of the optical signal, the optical signal having an intensity v. total dispersion characteristic curve with at least two peaks; and (ii) controlling the amount of total dispersion of the transmission line to substantially minimize the intensity of the specific frequency component between the two highest peaks of the intensity v. total dispersion characteristic curve of the optical signal. Assuming that the optical signal is modulated by a data signal having a bit rate of B bits/second, then the specific frequency component is preferably a B hertz component of the optical signal.

George Ishikawa

Papers

Optical wavelength multiplex transmission method and optical dispersion compensation method

Optical transmission system, optical multiplexing transmission system, and related peripheral techniques

Optimized optical transmission system for high capacity transmission

Compensation of pulse shape distortion due to chromatic dispersion and Kerr effect by optical phase conjugation

Method and apparatus for optimizing dispersion in an optical fiber transmission line in accordance with an optical signal power level