Abstract:
The invention relates to a method for delaying a signal in the form of a light pulse or a pulse packet, wherein the signal for splitting up the frequency components is first of all exposed to an element having a strong chromatic dispersion, wherein at least individual frequency components of the split signal are subjected to a modulation and wherein, in order to compensate the dispersion generated, the signal thus processed is exposed to an element having a corresponding dispersion with a reverse sign.
Abstract:
Photonic devices for generating linearly frequency modulated arbitrary microwave signals comprise a laser, and assembly for forming the emitted signal and a photoreceiver the passband of which is in the domain of the microwave frequencies. The forming assembly comprises: a first beam splitter; a first optical channel including a frequency-shifting loop comprising a beam splitter, a first optical amplifier, an optical isolator, a first spectral optical filter and an acousto-optical frequency shifter; a second optical channel including an electro-optical frequency shifter; a second beam splitter; a second optical amplifier; and a second optical filter; the acousto-optical frequency shift, the electro-optical frequency shift and the amplification gain of the first optical amplifier being adjustable.
Abstract:
This invention relates to opto-electronic systems using semiconductor lasers driven by optical phase-locked loops that control the laser's optical phase and frequency. Feedback control provides a means for precise, wideband control of optical frequency and phase, augmented further by four wave mixing stages and digitally stitched independent optical waveforms for enhanced tunability.
Abstract:
An optical buffer device includes plural optical memory elements that are capable of holding light and an optical delay element. The plural optical memory elements are arranged on an optical path through which signal light and control light propagate in mutually opposite directions. Further, the optical delay element is disposed between the optical memory elements that are adjacent to each other. The optical delay element imparts different delays to the signal light and the control light. According to a preferred exemplary embodiment of this optical buffer device, each of the optical memory elements includes an optical waveguide through which the signal light and the control light propagate and an optical resonator that is disposed in proximity to this optical waveguide, and a coupling between the optical waveguide and the optical resonator is generated or cancelled depending on whether or not the control light is inputted.
Abstract:
An apparatus and method are provided for filtering an optical signal by wavelength. An initially polarised signal is passed through a DGD element effective to alter the polarisation state of the components of the signal according to wavelength. A polarisation filter (polariser) is then provided to attenuate light having given polarisation states from the signal, thereby attenuating the wavelengths associated with said polarisation states. The invention finds particularly utility in the domain of vestigial sideband filtering, allowing the bandwidth of signals within a wavelength division multiplexed system to be reduced without introducing the deleterious effects associated with conventional wavelength filters.