摘要:
Optical transmission systems of the present invention include optical protection systems, apparatuses, and methods that provide increased reliability in the system. The optical system generally includes an optical switch having distinct, cooperating dedicated and shared protection sections. The shared protection sections in a plurality of nodes can be configured to provide a protection net, in which a plurality of traffic demands, or working channels, are commonly protected as protection group using one protection channels supported by the protection net.
摘要:
Wavelength division multiplexing, spatial switching cross-connect structures which may be deployed as intermediate nodes of an all optical network to route any input channel on any source fiber to any destination fiber at any available wavelength to achieve full connectivity between the nodes of the network. The non-blocking cross-connect structure comprises a wavelength division demultiplexer for receiving multiple wavelength channels from each source fiber and for separating received channels into N wavelengths so that the wavelengths are organized according to a corresponding fiber of origin, a nonblocking optical structure for spatially and independently rearranging the received wavelengths so that wavelengths having a common destination fiber are grouped together, and a wavelength division multiplexer for multiplexing together wavelengths having the same destination fiber.
摘要:
The present invention relates to an FET power amplifier whose transfer characteristics are parabolic or have a pronounced parabolic region. The amplifier is capable of linear operation due to a drain electrode bias network which includes a pair of serially connected quarter-wave transmission line sections connected at one end thereof to the drain electrode, and the interconnection point of the two quarter-wave transmission line sections is connected to both (a) a bias supply which causes the FET to operate over at least a portion of the parabolic region and (b) to a means which prevents envelope-induced drain bias voltage variations and presents a short-circuit to the drain terminal at a second harmonic of the input signal.
摘要:
The present invention relates to a linear, class A FET amplifier circuit capable of providing linear amplifier of input signals with a time-varying envelope function. An envelope detector (12) is responsive to an input signal (v.sub.i (t)) for extracting the envelope signal (V.sub.i (t)) therefrom. A gate controller (16) subsequently adds the envelope signal to a predetermined gate bias voltage (E.sub.G) and applies the sum (E.sub.G (t)) as the "d-c" gate input to the FET amplifier (14). Therefore, the gate bias voltage is dynamically controlled by the envelope of the input signal, resulting in a significant improvement in the power-added efficiency (.eta..sub.added) over prior art class A FET amplifiers.
摘要:
The present invention provides a device for performing wavelength add/drop multiplexing utilizing micromachined free-rotating switch mirrors. The free-space nature of the switch mirrors allow use of the front and back sides of the mirrors for reflecting signals. According to one embodiment of the present invention a WADM is provided in which micromachined switch mirrors are arranged in a polygonal (e.g., hexagonal) geometry, which allows full connectivity. According to one embodiment a WADM is provided for deployment in a unidirectional two-fiber optical network including service and protection fiber routes. According to this embodiment the WADM includes a first input port for receiving a WDM signal from the service fiber route and a second input port for receiving a WDM signal from the protection fiber route. The WADM also includes a first output port for transmitting a WDM signal to the service fiber route, a second output port for transmitting a WDM signal to the protection fiber route, a third input port for receiving locals signals from a local access port and a third output port for dropping signals to a local access port. The WADM further includes a reconfigurable switching matrix comprising a plurality of free-space micromirrors, for performing routing of signals from the various input ports to the various output ports. According to an alternative embodiment a WADM is provided for deployment in a bidirectional two-fiber optical network including two service/protection routes.
摘要:
An optical equalization receiver for countering the effects of delay distortion is realized by utilizing dynamically controllable Fabry-Perot etalon structures. By dynamically adjusting the frequency response of an etalon that is in a feedback loop configuration, the associated delay characteristic of the etalon may be used to counter the effects of delay distortion, thereby allowing higher transmission rates and transmission distances to be achieved. In one exemplary embodiment, an optical receiver comprising a reflective Fabry-Perot etalon and a piezoelectric transducer is used in a feedback loop configuration wherein a feedback control circuit monitors an output signal from the etalon for generating a control signal representing the amount of delay needed to compensate for distortion in an optical signal incident on the etalon. Specifically, the control signal causes a change in the optical path length of the etalon that results in a shift in its frequency response for producing a delay substantially equal and opposite to the associated delay distortion.
摘要:
The present invention relates to a N.times.N single-mode optical coupler employing evanescent wave coupling between mutually adjacent optical waveguides sufficiently close to one another to facilitate coupling among all the waveguides. An optical signal of a narrow frequency band, e.g. appreciably less than 100 gigahertz, introduced to an input port of one of the waveguides is found to be nonuniformly distributed among the output ports of the coupler. A first embodiment uses the nonuniform distributions of narrowband optical signals to the output ports of the coupler to enable the present invention to be used as essentially a selective switching device. A second embodiment introduces one or more predetermined broadband optical signals to one or more input ports of the coupler to produce an appreciably uniform power distribution among the output ports of the coupler. A third embodiment uses electrooptic or magnetooptic waveguides and the application of a high-frequency, continuously changing magnitude, oscillatory electric or magnetic field, respectively, throughout the coupling region of the waveguides to produce a substantially uniform power distribution among the output ports of the coupler for a narrowband optical signal applied to an input port of the coupler.
摘要:
The present invention relates to a technique for achieving cross-polarization interference (CPI) cancellation with or without equalization in a digital-radio, space-diversity communication system. More particularly, a present receiver includes a pair of spaced-apart diversity antennas, where each antenna is capable of receiving orthogonally polarized signals, e.g., Vertical and Horizontal polarizations, from a remote transmitter. The received orthogonally polarized signals from each antenna are separated and coupled to separate inputs of a separate cross-polarization canceler, where each canceler includes two straight-through and two cross-over paths including a separate complex gain multiplier disposed in each path. The correspondingly orthogonally polarized output signals from each of the cancelers are added to produce a first and a second orthogonally polarized overall canceler arrangement output signal. Power measurements are taken of the two overall output signals during predetermined periods of time to produce control signals in a Control and Dither means for appropriately adjusting the complex gain multipliers in each canceler and substantially cancel CPI while providing equalization where desired. Additionally, control signals can also be generated for transmission back to the remote transmitter for appropriately adjusting a canceler therein when CPI cancellation including a second order in frequency is desired.
摘要:
The present invention relates to an N-way non-hybrid power combiner arrangement for microwave amplifiers. In operation, sensing means (19.sub.1, 19.sub.2, . . . , 19.sub.N) are coupled in a one-to-one relationship with the individual amplifiers (12.sub.1, 12.sub.2, . . . , 12.sub.N) to monitor amplifier performance and sense amplifier failure. In one embodiment of the present invention, shorting devices (20.sub.1, 20.sub.2, . . . , 20.sub.N) are disposed adjacent to the outputs of the individual amplifiers and coupled to the associated sensing means in a one-to-one relationship. In an alternative embodiment, open-circuiting devices (30.sub.1, 30.sub.2, . . . , 30.sub.N) are disposed at a predetermined distance from the amplifier outputs along the transmission lines (24.sub.1, 24.sub.2, . . . , 24.sub.N) and coupled to their respective sensing means. Upon identifying amplifier failure, the sensing means coupled to that particular amplifier activates either its associated short-circuiting or open-circuiting device, which in turn uncouples the failed amplifier and the transmission line associated therewith.
摘要:
In an optical arrangement for amplifying an input lightwave signal by a predetermined amount to a desired output level, an optical amplifier is connected to a loss element. The optical amplifier is pumped by an amount exceeding a nominal amount wherein the nominal amount is the amount of pumping needed to attain the desired output level at the optical amplifier output. By attenuating the signal output from the optical amplifier, the loss element generates an output signal from the optical arrangement at the desired output level. This optical arrangement is characterized by an improved noise performance (noise figure) over standard optical amplifiers.