Method and system using optical phase modulation and optical phase demodulation and spectral filtering to generate an optical pulse train

Abstract

A method of generating an optical pulse train using spectral extension by optical phase modulation, spectral narrowing by optical phase demodulation, and narrow linewidth optical filtering is disclosed. It is also described that the wavelength selection of light using a chromatic dispersion element between the optical phase modulator can enrich the method. Systems include an in-line optical setup and a ring-type laser cavity for mode-locked laser outputs. The duration with which the electrical signals driving the modulators are opposed determines the line width of the optical pulses, and the opposite repetition of the electrical signals defines the rate of repetition of an optical pulse train generated. Four different arrangements of electrical signals in the time domain or phase domain make it possible to control the generation of optical pulses and the wavelength selection of the light. (i) A signal arrangement comprising sinusoidal electrical signals with a slight frequency difference. (ii) A signal arrangement comprising a phase-shift between electrical signals. (iii) A signal arrangement comprising a phase-shift between electrical signals depending on the amplitude of the bits. (iv) A signal arrangement comprising random electric waves that repeat themselves over a predefined period to allow the insertion of controllable time delays between each other.

Dependencies are inferred from the claim text.