Abstract: The present invention provides an optical switch including a loss element having a signal loss, and a rare earth doped gain element optically connected in series with the loss element. The rare earth doped gain element is operable to produce a signal gain. The signal gain and the signal loss are about equal. The present invention also provides a method of optical switching including optically connecting a loss element in series with a rare earth doped gain element and passing an optical signal through the loss element and the gain element. The loss element attenuates the optical signal by a first amount. The method further includes selectively applying an optical pump to the gain element to perform the switching, the gain element amplifying the optical signal by the first amount in response to the optical pump.

Abstract: The optical amplifier has a waveguide including a core and a cladding. The cladding at least partially surrounds the core and is doped with at least one species of rare earth ion in the range of 5 to 75 wt %. In another embodiment, the core is doped with Er3+ in the range of 7 to 9 wt % and with Yb3+ in the range of 11 to 13 wt %.

Abstract: A flattened gain amplifier has a waveguide with a core doped with at least one species of rare earth ion. The rare earth ion has a gain profile with a first gain in a first wavelength band and a second gain in a second wavelength band. The flattened gain amplifier also has a first grating and a reflective element optically coupled to the core. The positions of the first grating and reflective element along the length define a first amplifying length and a second amplifying length. The ratio of the first amplifying length to the second amplifying length is about equal to the ratio of the second gain to the first gain.

Abstract: The present invention provides an optical switch including a loss element having a signal loss, and a rare earth doped gain element optically connected in series with the loss element. The rare earth doped gain element is operable to produce a signal gain. The signal gain and the signal loss are about equal. The present invention also provides a method of optical switching including optically connecting a loss element in series with a rare earth doped gain element and passing an optical signal through the loss element and the gain element. The loss element attenuates the optical signal by a first amount. The method further includes selectively applying an optical pump to the gain element to perform the switching, the gain element amplifying the optical signal by the first amount in response to the optical pump.

Abstract: A variable optical attenuator including a loss element and a rare earth doped gain element in optical communication with the loss element, the rare earth doped gain element having a gain responsive to an optical pump.

Abstract: An integrated-optic attenuator/equalizer device comprising a photorefractive substrate, at least one optical waveguide channel formed in the substrate, at least one diffractive-Bragg grating formed in the substrate, and a diffractive-Bragg grating modulator that is capable of modulating the diffractive Bragg grating(s). The diffractive-Bragg grating(s) intersects the optical waveguide channel. When a diffractive-Bragg grating formed in the substrate is modulated, at least a fraction of light of a wavelength associated with the modulated diffractive-Bragg grating is re-directed by the modulated diffractive-Bragg grating, thereby preventing the re-directed fraction of light from arriving at the output of the optical waveguide channel.

Abstract: An integrated-optic device comprising a photorefractive substrate, an optical waveguide channel and at least one diffractive Bragg grating integrated in the substrate and intersecting the optical waveguide channel. The diffractive Bragg grating(s) causes at least a fraction of light coupled into the optical waveguide channel to be coupled out of the optical waveguide channel.

Abstract: An integrated-optic attenuator/equalizer device comprising a photorefractive substrate, at least one optical waveguide channel formed in the substrate, at least one diffractive-Bragg grating formed in the substrate, and a diffractive-Bragg grating modulator that is capable of modulating the diffractive Bragg grating(s). The diffractive-Bragg grating(s) intersects the optical waveguide channel. When a diffractive-Bragg grating formed in the substrate is modulated, at least a fraction of light of a wavelength associated with the modulated diffractive-Bragg grating is re-directed by the modulated diffractive-Bragg grating, thereby preventing the re-directed fraction of light from arriving at the output of the optical waveguide channel.

Abstract: An integrated-optic device comprising a photorefractive substrate, an optical waveguide channel and at least one diffractive Bragg grating integrated in the substrate and intersecting the optical waveguide channel. The diffractive Bragg grating(s) causes at least a fraction of light coupled into the optical waveguide channel to be coupled out of the optical waveguide channel.

Abstract: A rapid increase in motor current (di/dt above a predetermined threshold) causes the motor control system to enter pulse mode operation in-which the motor current is pulsed on and off rapidly to dislodge the workpiece obstruction or binding condition that would otherwise lead to a motor stall. When the workpiece obstruction or binding has been cleared, the motor resumes normal operation.