Abstract: An optically biased photonic link receives a radio frequency (RF) signal and includes a signal laser joined to an optical intensity modulator. A low noise amplifier receives the RF signal and provides an amplified signal to the modulator. The modulator converts the signal into an optical signal. The amplifier and modulator are powered by a photovoltaic array. The array receives power from a remotely located power laser. The optical signal is received by a link receiver which provides an analysis signal and an output signal. A bias logic circuit uses the analysis signal to provide an optical bias signal to an optical detector joined to modulator. The optical detector provides a responsive bias voltage to the modulator.

Abstract: An active optical modulator receives a radio frequency signal and provides an intensity modulated optical signal. The optical modulator is formed on a substrate having a doped region. An interferometer is formed on the substrate having a first path and a second path. A low noise amplifier receives the radio frequency signal and provides an electrical field to the paths. A signal laser provides an optical signal to the interferometer which is modulated and interfered to produce an intensity modulated optical signal. A pump laser provides an optical gain signal to the interferometer where it adds gain to the optical signal in the interferometer by interaction with the doped region of the substrate.

Abstract: A range finder includes a plurality of modulated seed lasers providing light at different wavelengths. Light from the seed lasers is provided to a wideband laser fiber amplifier. A portion of amplified laser light is directed to a first detector. The remainder is transmitted to a target through a collimating lens. Reflections from the target are received by a telescope. A major portion of the returned light is provided to a second detector. A minor portion is provided as feedback to the wideband laser fiber amplifier for stabilization. Outputs from the first and second detector are provided to a processor. Processor analyzes the time delay between the transmitted light and the reflected light to provide a range output. Other embodiments could use adaptive optics and mode hopping range calculations.

Abstract: A laser communication apparatus is provided for sending and receiving messages. A processor encodes user messages for a modulator. The modulator provides control signals related to the encoded message to a plurality of seed lasers. Each seed laser can provide light at a different wavelength. Amplifiers are joined to amplify light from the seed lasers. Amplified light is multiplexed together. Multiplexed light is transmitted by a collimating lens along a target vector. A portion of the light can be monitored by a first detector. A telescope receives light from the target vector and provides focused light to a second detector. The second detector provides a signal responsive to the received light to the processor. The processor decodes this signal to provide the received message.

Abstract: A method of optical signal amplification. Incident photons are received at a photodetector including a doped semiconductor biased by a power source. The photons generate a change in a reflective property, refractive index, or electrical conductivity of the doped semiconductor. For the change in reflective property or refractive index, a first optical signal is reflected off the photodetector to provide a reflected beam, or the photodetector includes a reverse biased semiconductor junction including the doped semiconductor within a laser resonator including a laser medium, wherein a second optical signal is emitted. For the change in electrical conductivity the photodetector includes a reversed biased semiconductor junction that is within an electrical circuit along with an electrically driven light emitting device, where a drive current provided to the light emitting device increases as the electrical conductivity of the photodetector decreases, and the light emitting device emits a third optical signal.

Abstract: An optical output photodetector includes a substrate having a semiconductor surface and at least one optical photodetector element on the semiconductor surface. The optical photodetector element includes a plurality of integrated sensing regions which collectively provide a plurality of different absorbance spectra. The plurality of sensing regions includes a plurality of different semiconductor materials or a semiconductor material having a plurality of different dopants. The optical photodetector element can be configured as an array of optical photodetector elements and the dopants can be magnetic dopants.

Abstract: An image analysis system and method are provided. The system can include a base for receiving an optical surface, at least one light source positioned above and at an oblique angle with respect to the optical surface, a camera positioned above the optical surface and adapted to provide an image data indicative of an image of the optical surface, and a computerized system adapted to receive the image data from the camera. The computerized system can analyze the image data to identify and quantify surface defects. Classification identifiers can be assigned to each surface defect based on the physical characteristics of the surface defect. A transmission metric is calculated for the optical surface to allow objective judgment of the surface.

Abstract: A method of optical signal amplification. Incident photons are received at a photodetector including a doped semiconductor biased by a power source. The photons generate a change in a reflective property, refractive index, or electrical conductivity of the doped semiconductor. For the change in reflective property or refractive index, a first optical signal is reflected off the photodetector to provide a reflected beam, or the photodetector includes a reverse biased semiconductor junction including the doped semiconductor within a laser resonator including a laser medium, wherein a second optical signal is emitted. For the change in electrical conductivity the photodetector includes a reversed biased semiconductor junction that is within an electrical circuit along with an electrically driven light emitting device, where a drive current provided to the light emitting device increases as the electrical conductivity of the photodetector decreases, and the light emitting device emits a third optical signal.

Abstract: An optical fiber coupler includes a clad optical fiber core having a coupling window formed therein. A laser source is joined to emit light into the core through the coupling window. The core has an output coupler for partially reflecting a portion of light and transmitting a portion as output. A Bragg grating is formed in the core having a pitch and being positioned to reflect light from said laser source toward the output coupler. The pitch is variable in response to a temperature change. A thermal control device is joined to the core for adjusting its temperature and the Bragg grating pitch. In other embodiments a mode convertor is provided to reduce the output modes to selected modes.

Abstract: A mode-locked laser amplifier utilizing free-space optical feedback is provided. The amplifier may tap a portion of the input laser signal and tap a portion of the output laser signal, combine the input and output samples in a free-space coupler to form a feedback laser signal, and couple the feedback laser signal back to the input laser signal. The free-space coupler suppresses higher order modes of the output laser signal. The free-space coupler can be tunable to permit selection of the operating mode of the amplifier. A plurality of amplifiers can be utilized to form a multi-stage mode-locked amplifier system. The composite feedback signal can be coupled back to each amplifier stage to lock the operating mode.

Abstract: An optical output photodetector includes a substrate having a semiconductor surface and at least one optical photodetector element on the semiconductor surface. The optical photodetector element includes a plurality of integrated sensing regions which collectively provide a plurality of different absorbance spectra. The plurality of sensing regions includes a plurality of different semiconductor materials or a semiconductor material having a plurality of different dopants. The optical photodetector element can be configured as an array of optical photodetector elements and the dopants can be magnetic dopants.

Abstract: Embodiments of the present disclosure provide systems, devices, and methods for photodetection. For example, briefly described, in one embodiment among others, a sensor comprises an array of photodetectors, wherein the reflectance of each of the photodectors is a function of the number of photons incident on the respective photodetector; and an electrical insulator positioned between one of the photodetectors and another one of the photodetectors to reduce diffusion of electrons therebetween.

Abstract: A side-pumped fiber laser includes an optical fiber having a core and a cladding. The core has an index of refraction n1 and the cladding has an index of refraction n2, wherein n1 is greater than n2. The fiber further includes a coupling window integrally formed within a channel formed in an upper side of fiber cladding. The coupling window consists of an optical material having an index of refraction n3 wherein n3 is greater than n1. The fiber laser further includes a laser light source that is directed through the coupling window wherein laser light is directly coupled into the core of the fiber. The fiber of the fiber laser also preferably includes Bragg gratings written into the core beneath the coupling window and a reflective material disposed in a second window formed beneath the Bragg gratings.

Abstract: An optical amplifier (18) for proposed use in a free-space optical network includes a multi-clad optical fiber (10) having a single-mode core (12) doped with a rare-earth laser active dopant, a passive inner cladding (14) surrounding the core (12), and at least one outer cladding (16) surrounding the inner cladding (14). The amplifier (18) further includes a source of pump light (20) that is coupled directly into the core (12), and a source of signal light (22) that is coupled into the inner cladding (14). The signal light (30, 32) collected in the inner cladding (14) propagates along the optical fiber (10) for a distance sufficient for the signal light (32) to couple into the core (12) and for the signal light (32) to be amplified by the amplifying light (28) emitted within the core (12).

Abstract: An optical feedback control system utilizes one or more linear photodiode arrays to map the optical characteristics of an optical signal at a plurality of different wavelengths over an entire communication spectrum. The data gathered from the linear photodiode arrays is actively used to control gain and gain flatness of a fiber optic amplifier system or other optical fiber device, such as a fiber laser.

Abstract: An ultra-wide bandwidth optical amplifier for the 1.5 &mgr;m optical band divides the 1520 nm-1610 nm bandwidth into three narrow bandwidths, i.e. C1 (1520 nm-1541 nm), C2 (1541 nm-1565 nm) and L (1565 nm-1610 nm), and uses three separate erbium doped fiber amplifier blocks, configured in parallel relation and individually optimized to separately amplify the respective bandwidth. Multipath interference is controlled by constructing all three amplifier blocks with the same optical transmission length. The C1 and C2 band amplifier blocks, which include shorter erbium doped fibers than the L band amplifier block, are physically lengthened using lengths of single mode fiber so that the total length of the optical transmission path of each amplifier block is generally equal. Fiber lengths are controlled to within 500 microns.