Abstract: A method and system for controlling the fabrication of an optical device having a given property at a defined wavelength. The method comprises the steps of providing a substrate, depositing a material on the substrate to form a film thereon, and controlling a set of manufacturing parameters as the film is being formed on the substrate to make the optical device. The method comprises the further steps of generating an optical signal having a given wavelength, dithering the wavelength of the optical signal, and applying the dithered optical signal to the film being formed on the substrate to modulate the optical signal. A correlation signal is generated to represent the difference between the given wavelength and the defined wavelength, and that correlation signal is used to adjust at least one of the manufacturing parameters to make the optical device with said given property at the defined wavelength.

Abstract: An NRZ to RZ conversion arrangement with a mode-locked laser, a wavelength locked feedback loop, and a disk shaped variable optical density filter wheel having a plurality of different filter components, filter 1, filter 2, filter 3, . . . filter n circumferentially spaced therearound. The disk filter wheel is driven to rotate about its central axis by a motor, with the filter being positioned in an external laser cavity having the laser and an external cavity mirror with diffraction grating rulings, which forms a frequency mode selective component. The disk filter is positioned parallel to the external cavity mirror, and by rotating the disk filter the wavelength of the mode locked laser is selectively tuned.

Abstract: A system and method for precisely controlling the wavelength selective function provided by fiber Bragg gratings in optical fiber elements. The system and method exploits a wavelength-locked loop servo-control circuit and methodology that enables real time adjustment of the grating pattern being written to said fiber optical link element by a grating writing source to thereby mutually align a center wavelength of the peaked wavelength selective function resulting from the grating pattern with a center wavelength of the optical signal transmitted over a communication channel provided by the fiber. A real-time adaptive dispersion compensation technique for optical fibers is additionally provided that exploits the wavelength-locked loop servo-control circuit.

Abstract: An optical control monitor and a method for adjusting for changes in optical signals transmitted through an optical network. The method comprises the steps of transmitting a set of optical signals through a network, each of the optical signals having a respective wavelength; and tracking changes to said set of signals by passing each of the signals through a filter having a bandpass function, and dithering the filter bandpass about the wavelengths of each of said set of signals to generate filter output signals. The filter output signals are used to adjust the network or the set of optical signals to compensate for said changes.

Abstract: A method and system for modulating an optical signal to encode data therein. The method comprises the steps of directing the optical signal through a filter mechanism having a passband function including a center wavelength, and modulating the center wavelength of the optical signal to establish a difference between the center wavelengths of the filter mechanism and the optical signal to represent a data value. With the preferred implementation of the invention, a transmit device is used to encode the data in the optical signal, and a receive device is provided to decode the signal. The transmit device modulates the center wavelength of the optical signal to establish a difference between the center wavelength and a predefined wavelength to encode data in the optical signal, and the transmit device then transmits the optical signal. The receive device receives the optical signal from the transmit device and processes that signal to identify the encoded data.

Abstract: A method and system for synchronizing a local optical clock with a master optical clock, wherein the local clock generates a local clock signal at a local clock wavelength, and said master clock generates a master clock signal at a master clock wavelength. The method comprises the steps of dithering the wavelengths of the local and master clock signals, and generating a control signal representing the difference between the dithered wavelengths of the local and master clock signals. That control signal is then used to synchronize the local clock with the master clock. Preferably, a wavelength-locked loop is used as a means of phase or wavelength control for the optically distributed clock signals. The wavelength-locked loop provides a technique to control the wavelength of a local optical clock source in a manner that will allow the local clock to follow variations in the wavelength of another optical signal.

Abstract: Wavelength locked feedback loops are provided in frequency guide filters, and particularly in sliding frequency guide filters, wherein the wavelength locked feedback loop allows precise control over the location of the filter center wavelength with respect to a transmitted soliton center wavelength, compensating for factors such as the filter rolloff, signal spectral width, and changes in the transmission line properties due to temperature, microbending, aging and other effects. This approach allows the construction of very inexpensive frequency guiding filters, which can be based on low precision frequency domain filters with active compensation. These advantages make it possible to design new types of dispersion managed soliton optical transmission networks.

Abstract: A system and method for optimizing performance characteristics of optical networks. The system and method exploits a wavelength-locked loop servo-control circuit and methodology that enables real time adjustment of optical signals in accordance with attenuation characteristics of an optical transmission channel. Particularly, the invention enables alignment of optical signal center wavelengths and optical wavelength selective devices exhibiting a peaked passband function in optical networks utilizing information included in first derivative and second derivatives of dither modulated optical signals extracted from a feedback signal provided in the wavelength-locked loop servo-control circuit.

Abstract: An arrangement for tuning a micro-electro-mechanical (MEM) laser center wavelength to exactly match the passband of its associated filter. A dither wavelength locked feedback loop dynamically adjusts the position of the MEM element, and hence the laser wavelength, to keep it nominally centered at the filter passband peak. The dither wavelength locked feedback loop compensates for many internal variables of the laser, filter, and the MEM with a single mechanism that stabilizes the laser and locks the wavelength to any desired value.

Abstract: A system and method for automatically attenuating optical signals transmitted in optical systems. The system and method exploits a wavelength-locked loop servo-control circuit and methodology that enables real time mutual alignment of the center wavelength of an optical signal having a peaked spectrum function and transmitted through the optical system, and a center wavelength of a wavelength selective device such as an optical filter element implementing a peaked passband function. The wavelength-locked loop servo-control circuit and methodology particularly is capable of real-time aligning the center wavelength of an optical signal in a range between maximum overlap with the center wavelength of the peaked passband function of the optical filter for maximum transfer of output optical signal by the filter element and minimum overlap with the peaked passband function of the optical filter so that output optical signal may be attenuated in the optical system.

Abstract: A system and method for precisely controlling the wavelength of short wavelength optical signals being communicated via a fiber optic link in an optical system. The system comprising a configuration of optical filter elements each having a peaked passband function capable of passing short wavelength optical signals, the optical filter elements being in a nested configuration with a first optical filter element having a peaked passband function capable of passing short wavelength optical signals within a first range of wavelengths for input to a next successive optical filter stage; each successive optical filter stage of the nested configuration capable of passing wavelengths within successively narrower wavelength ranges within the first range of wavelengths.

Abstract: Electrically switchable optical elements, such as application specific integrated elements including filters, lenses and switches, are combined with wavelength locked feedback loops. Electrically Switchable Bragg Grating (ESBG) technology is combined with a wavelength locked feedback loop to provide variable focal length optical systems which automatically adjust the focal length of incident light.

Abstract: A system and method of compensating for optical polarization dispersion effects exhibited in a length of optical fiber in an optical network. The system and method exploits a wavelength-locked loop servo-control circuit and methodology that detects a polarization mode dispersion characteristic of the optical signal and enables real time adjustment of the center wavelength of the optical in manner so as to minimize polarization effects in the optical fiber link. In another embodiment, the wavelength-locked loop servo-control circuit and methodology is implemented for enabling real time physical adjustment, e.g., X-Y dimension strain control, of the optical fiber link itself in accordance with the detected amount of polarization mode dispersion.

Abstract: A system and method for improving optical signal gain efficiencies of semiconductor optical amplifier devices. The system and method exploits a wavelength-locked loop servo-control circuit and methodology that enables real time mutual alignment of the center wavelength of an optical signal having a peaked spectrum function and transmitted through the semiconductor optical amplifier, and a center wavelength of a wavelength selective device such as an optical filter implementing a peaked passband function in an optical system. The wavelength-locked loop servo-control circuit and methodology may be further exploited to control various types of modulation applied to the optical signals transmitted in optical systems.

Abstract: A system and method for controlling alignment of a laser center wavelength and Raman filter passband center wavelengths in a Raman effect optical amplifier for purposes of providing increased gain response. The system and method exploits a wavelength-locked loop servo-control circuit and methodology that enables real time mutual alignment of a laser pump signal having a peaked spectrum function including a center wavelength and the center wavelength of a passband filter having a peaked passband function provided in the Raman amplifier.

Abstract: A method and system for dispersion control of electromagnetic signals in communication networks by narrowing the widths of electromagnetic pulses such as modulated laser signals. Generally, in the preferred embodiment, the present invention utilizes a feedback loop based on dither frequency modulation which dynamically adjusts the alignment of the laser center frequency with the filter passband. In this way, there is an acceptable tradeoff between optical power and pulse width, so a higher power laser can be used to generate a narrower optical pulse. The narrower pulses then travel farther in the fiber link before reaching their dispersion limit. It is believed that, by using this invention, existing link distance could be doubled, while re-using existing installed singlemode fiber.

Abstract: A system and method for controlling alignment of laser center wavelengths and filter passband center wavelengths in optical amplifiers for purposes of providing automatic gain control and eliminating unwanted noise. The system and method exploits a wavelength-locked loop servo-control circuit and methodology that enables real time mutual alignment of a laser pump signal having a peaked spectrum function including a center wavelength and a wavelength selective device such as an optical filter implementing a peaked passband function including a center wavelength in an optical amplifier.

Abstract: A wavelength-locked loop servo-control circuit and methodology that enables real time mutual alignment of an electromagnetic signal having a peaked spectrum function including a center wavelength and a wavelength selective device implementing a peaked passband function including a center wavelength, in a system employing electromagnetic waves.

Abstract: In a system for writing a plurality of information tracks between adjacent portions of a reference track on a rotatable medium, advantage is taken of the fact that laser beam dithering a cross an edge of a reference track produces signals which are analyzable to determine much more exact radial positions. A pattern of bits is written on the medium with a known spacing between bits. This may be at the time of disk manufacture or later. As these bits are being read, a clock is started along with a bit counter. At this time, a precise determination is made of the radial position at which the read bits are present. From these values, angular and/or linear velocities are computed and stored on the medium. Collected over time, this information is useful for determining aging characteristics of the drive mechanism for the medium.

Abstract: A photolithographic process is provided for producing a blank storage disk which includes a reference track pattern. The track pattern provides two edges as reference lines from which distances are determinable for the purpose of laser writing multiple information tracks between adjacent reference track patterns which are preferably spirals (single or interlaced) or concentric circles. The photo-lithographic process is also used to create recording blanks having multiple layers.