A Self-sustained Soliton Oscillator Utilizing Nonlinear Transmission Lines and Spectrum-preservice Nonlinear Amplification

Background

Conventional traveling wave oscillators that require high-speed clock signals generally employ a linear transmission line over which sinusoidal waves are propagated. In such systems, linear amplifiers are employed to overcome resistive losses present in the transmission line so as to maintain the signal strength of the traveling sinusoidal wave and permit oscillation. While such linear oscillator systems have enjoyed wide acceptance in the communications industry, system designers have expressed a willingness to consider nonlinear approaches.

Invention

The invention describes new methods and apparatus for implementing stable self- starting and self-sustaining electrical nonlinear pulse (e.g., soliton, cnoidal wave, or quasi-soliton) oscillators. In one embodiment, a nonlinear pulse oscillator is implemented as a closed loop structure that comprises a nonlinear transmission line, a high-pass filter, and a nonlinear amplifier configured to provide a self-adjusting gain as a function of the average voltage of the oscillator signal (i.e., the propagating pulses). In another aspect, an adaptive bias control technique is employed together with the nonlinear gain functionality to ensure robust, stable operation of the oscillator. The implementation of a nonlinear amplifier with adaptive bias control may be viewed conceptually as an electric circuit analog of a saturable absorber, which is configured to effectively reduce distortion to pulses propagating in the oscillator, reject perturbations to the system, and ensure the selection and propagation of a single mode. In yet another aspect, one or more high pass filters employed in the oscillator may be particularly configured to facilitate single mode operation. For example, according to one embodiment, the cut-off frequency of one or more high pass filters is particularly selected so as to prohibit collisions of multiple different-amplitude nonlinear pulses. The filter design takes advantage of the fact that collisions of multiple different amplitude solitons or quasi-solitons tend to skew the frequency spectrum of the oscillator toward higher power at lower frequencies. Accordingly, by designing the high pass filter to appropriately attenuate lower frequency spectrum components characteristic of soliton collisions, such collisions are effectively precluded from forming in the oscillator.

Background

Conventional traveling wave oscillators that require high-speed clock signals generally employ a linear transmission line over which sinusoidal waves are propagated. In such systems, linear amplifiers are employed to overcome resistive losses present in the transmission line so as to maintain the signal strength of the traveling sinusoidal wave and permit oscillation. While such linear oscillator systems have enjoyed wide acceptance in the communications industry, system designers have expressed a willingness to consider nonlinear approaches.

Invention

The invention describes new methods and apparatus for implementing stable self- starting and self-sustaining electrical nonlinear pulse (e.g., soliton, cnoidal wave, or quasi-soliton) oscillators. In one embodiment, a nonlinear pulse oscillator is implemented as a closed loop structure that comprises a nonlinear transmission line, a high-pass filter, and a nonlinear amplifier configured to provide a self-adjusting gain as a function of the average voltage of the oscillator signal (i.e., the propagating pulses). In another aspect, an adaptive bias control technique is employed together with the nonlinear gain functionality to ensure robust, stable operation of the oscillator. The implementation of a nonlinear amplifier with adaptive bias control may be viewed conceptually as an electric circuit analog of a saturable absorber, which is configured to effectively reduce distortion to pulses propagating in the oscillator, reject perturbations to the system, and ensure the selection and propagation of a single mode. In yet another aspect, one or more high pass filters employed in the oscillator may be particularly configured to facilitate single mode operation. For example, according to one embodiment, the cut-off frequency of one or more high pass filters is particularly selected so as to prohibit collisions of multiple different-amplitude nonlinear pulses. The filter design takes advantage of the fact that collisions of multiple different amplitude solitons or quasi-solitons tend to skew the frequency spectrum of the oscillator toward higher power at lower frequencies. Accordingly, by designing the high pass filter to appropriately attenuate lower frequency spectrum components characteristic of soliton collisions, such collisions are effectively precluded from forming in the oscillator.

Applications Improved nonlinear pulse oscillator methods and apparatus may be employed in the areas of high-speed electronics, electrical and optical communication systems, information encoding and decoding, pulsed power technology, spectroscopy, and neural networks. For Further Information Please Contact the Director of Business Development Daniel Behr Email: daniel_behr@harvard.edu Telephone: (617) 495-3067

Inventor(s): Ham, Donhee

Type of Offer: Licensing



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