Abstract: A method and apparatus to enable the use of low cost high RIN optical sources for microwave photonic links by combining the wide-gain bandwidth and low cost of an EDFA, with the narrow gain bandwidth of a Brillouin amplifier. The hybrid Brillouin/EDFA (“hybrid amplifier”) apparatus of the present invention includes at least two couplers, a phase modulator, an Erbium-doped fiber, a laser source to pump the Erbium fiber, an optical circulator, and a length of fiber used for Brillouin amplification. Optical signals from the laser source are split into two optical paths by a polarization maintaining coupler. Optical signals passing through a first path are amplified by the Erbium doped fiber, and the amplified signals are passed through the optical circulator before sending the optical signals into one end of a spool of fiber in order to pump the Brillouin acoustic wave.

Abstract: Optical amplification systems and methods are disclosed. A first optical amplification system includes an optical interface filter configured to separate a desired communications band from at least one other communications band, and an optical amplifier in communication with the interface filter for amplifying the desired communications band. The optical amplifier includes at least one suppression filter configured to attenuate a wavelength subset of the at least one other communications band nearest the desired communications band and narrower than the at least one other communications band.

Abstract: An apparatus for transporting an optical signal is provided comprising at least two sections of optical fiber, a directional wavelength selector positioned between the at least two sections of optical fiber wherein the directional wavelength selector selectively blocks wavelengths propagating in a reverse direction, and a pump light emitting device optically coupled to the optical fiber.

Abstract: An optical device including an optical amplifier to amplify optical signals received through an optical input, and to supply the amplified optical signals from an optical output, and an optical filter coupled to the optical amplifier. The optical filter changes the gain slope of the optical amplifier in response to a change in a single parameter of the optical filter. The single parameter may be a change in a central wavelength of the optical filter function. The optical filter preferably has a parabolic spectral function. The single parameter may be varied as a function of temperature such that the variable optical attenuator compensates for variations in the gain spectrum of the optical amplifier that occur as a function of operating temperature.

Abstract: An optical amplification block is disclosed, which makes possible the shared use of an optical receiver element so that the configuration of one optical receiver element and of a driving circuit for driving the one optical receiver element to be reduced. The optical amplification block includes an optical amplification media for making an optical amplification; a first branching device to input signal lights and branch the signal lights into first branched lights and second branched lights, in a predetermined proportion, and input the first branched lights to the optical amplification media; and a second branching device to input the output of the optical amplification media and the second branched lights, the second branching device branching the input lights into third branched lights as optical amplified output and fourth branched lights as monitor lights.

Abstract: A waveguide for amplifying electromagnetic radiation of a characteristic wavelength includes a first reflector, a second reflector, and a gain medium having a characteristic wavelength of emission disposed between the first and second reflectors. The first and second reflectors are spaced apart from each other to form a microcavity which is off-resonance with respect to the characteristic wavelength of light emitted by the excited gain medium.

Abstract: The present invention aims at providing a controlling apparatus and a controlling method for a wavelength division multiplexing optical amplifier to reduce the controlling error due to the affection of noise light included in the monitoring light to be used for controlling the wavelength division multiplexing optical amplifier, to thereby realize precise controlling of the optical amplifier. To this end, the controlling apparatus for a wavelength division multiplexing optical amplifier according to the present invention: branches, by a photocoupler, a portion of WDM signal light amplified by a light level controlling part; and separates the thus branched light into groups of even-numbered channel components and odd-numbered channel components making use of a wavelength channel separate filter. Further, monitor signals corresponding to the light powers of the even-numbered group and odd-numbered group, respectively, are generated by respective photoelectric converting parts and LPF's.

Abstract: A noncollinear pumped solid state Raman laser or amplifier has a pump laser that transversely or noncollinearly pumps a solid state Raman gain material, with an intensity sufficient to produce a stimulated Raman laser output beam. The pump beam and the Raman beam are noncollinear when the Raman beam travels completely across the pump beam within the Raman gain material, or where the Raman beam completely separates physically, at some location in the pumped Raman gain material, from a virtual beam, which is collinear to the pump beam axis, and which has the same entrance spot size and beam divergence as the Raman beam. The device enhances the pump laser beam spatial homogenization to improve the wavefront smoothness and propagation performance from the pump beam to the Raman beam.

Abstract: An optical gain fiber of the present invention is doped with rare earth ions for improving a gain efficiency of a certain transition of the rare earth ions by inhibiting an undesirable amplified spontaneous emission. The optical gain fiber for amplifying an optical signal, includes a core doped with a first rare-earth ion in a portion thereof for amplifying the optical signal, and a clad doped with a second rare earth ion for absorbing an undesirable amplified spontaneous emission (ASE) emitted from the first rare earth ion, wherein the portion of the core and the potion of the clad are separated by the remaining portions of the core and the clad.

Abstract: Optical channel monitor depolarizers are provided. The depolarizers may be used to reduce the effects of polarization-dependent loss on optical channel power measurements made in optical amplifiers or other optical network equipment. The channel power measurements may be used in controlling optical amplifiers and other equipment in wavelength-division-multiplexing communications links.

Abstract: An optical device including an optical amplifier to amplify optical signals received through an optical input, and to supply the amplified optical signals from an optical output, and an optical filter component to compensate for variations in the gain spectrum of the optical amplifier that occur as a function of wavelength and operating temperature. The optical filter component includes a first optical filter having an athermalized transmission spectrum and a second optical filter having a transmission (or insertion loss) spectrum that varies as a function of operating temperature.

Abstract: In an optical amplifier using a rare earth element-doped optical fiber such as an erbium-doped optical fiber, a variation of amplification gain resulting from temperature change is suppressed and the gain-temperature characteristic is enhanced. Moreover, the quantity of temperature compensation in the gain is easily adjustable. Light from an excitation light source is input to an optical fiber for optical amplification comprising a rare earth element-doped optical fiber, via a temperature compensation optical fiber comprising a rare earth element-doped optical fiber such as an erbium-doped optical fiber. By changing the length of this temperature compensation optical fiber, the quantity of temperature compensation is finely adjusted.

Abstract: A wideband optical amplifier for amplifying an input optical signal of known wavelength in one of at least two bands of wavelength has a significantly small number of optical components and thus is low cost. The wideband optical amplifier includes: a first set of a first optical coupler, a first pump light source, and a first erbium doped optical fiber (EDF) which is excited by the first pump light source; an optical switch for changing an output signal of the first set; and a second set of a second optical coupler, a second pump light source, and a second EDF which is excited by the second pump light source. The first set amplifies a first band of optical signal while a series connection of the first set and the second set amplifies a second band of optical signal. In another aspect, a wideband variable wavelength optical source is achieved by utilizing the wideband optical amplifier described above within a closed loop.

Abstract: The present invention is to provide an automatic gain-controlled optical fiber amplifier, comprising: a first optical branch for branching a portion of an optical signal inputted into the optical fiber amplifier; a second optical branch for branching a portion of an optical signal outputted from the optical fiber amplifier; an optical distributor for receiving the optical signal of an input side branched partially by the first optical branch and for outputting it separately; a first wavelength selector for receiving the optical signal of a one side distributed by the optical distributor and for selecting a predetermined wavelength optical signal; a second wavelength selector for receiving the optical signal of an output side branched partially by the second optical branch and for selecting the predetermined wavelength optical signal; a signal processor for receiving the optical signal of a second side distributed by the optical distributor and the predetermined wavelength optical signal selected by the first

Abstract: The object of this invention is to improve SNR in the Raman amplification. An optical fiber (10) consists of a dispersion shift fiber in which a zero dispersion wavelength is shifted to the 1.55 &mgr;m band, and an optical fiber (12) consists of a single mode optical fiber having the effective core area of 100 &mgr;m2 which is larger than that of the optical fiber (10). An optical coupler 14 is disposed at the optical signal emission end of the optical fiber (12). A laser diode (16) outputs the laser light of 1455 nm as a Raman pumping light source. The output light from the laser diode (16) is introduced into the optical fiber (12) from the back, namely in the opposite direction to that of the optical signal propagation. The ratio of the Raman gain coefficient of the optical fiber (12) to that of the optical fiber (11) should be 1/1.08 or less, preferably 1/1.1 or less.

Abstract: Circuitry and a concomitant methodology for generating a burst support signal to augment an input bursty optical signal in an optical channel. The burst support signal is produced whenever the input bursty optical signal falls below a predetermined threshold. The burst support signal is the result of self-oscillation of a semiconductor optical amplifier and a tunable optical feedback loop. The wavelength of the self-oscillation is determined by the operating characteristic of the feedback loop.

Abstract: In a method of amplifying optical input signals over a wide bandwidth, the optical input signals are applied to an optical waveguide made from a rare-earth-doped amorphous material (e.g., erbium-doped yttrium aluminum oxide material). The optical input signals include optical signals having wavelengths over a range of at least 80 nanometers, and, preferably, over a range of at least 160 nanometers. Pump light is applied to the optical waveguide to cause the waveguide to provide optical gain to the optical input signals. The optical gain causes the optical signals to be amplified within the waveguide to provide amplified optical signals over the extended 80-160-nanometer range, including, in particular, optical signals having wavelengths at one end of the range and optical signals having wavelengths at a second end or the range.

Abstract: An optical signal amplifier includes a Raman fiber amplifier and a semiconductor optical amplifier. The Raman fiber amplifier utilizes pump radiation to amplify the optical signal resulting in an amplified optical signal. The semiconductor optical amplifier receives the amplified signal amplifying the amplified signal resulting in a twice amplified signal.

Abstract: An object of the invention is to provide, for an optical amplifier which performs amplification of optical signals of two wavelength bands, an optical amplifier and an optical amplification method of a simple configuration which can deal with restrictions on installation space, power consumption and the like. Hence with the optical amplifier of the invention, optical circulators are respectively connected to opposite ends of an optical amplifying means, and optical signals of the respective wavelength bands of a first wavelength band and a second wavelength band are input and output to the optical amplifying means via each of the optical circulators so that the propagation directions of the respective optical signals of the respective wavelength bands are in mutually opposite directions inside a rare earth element doped fiber. As a result, the optical signals of the respective wavelength bands can be collectively amplified with a simple configuration using a single rare earth element doped fiber.

Abstract: Techniques for producing optical pulses based on Brillouin selective sideband amplification by using a common modulation control signal to modulate both a signal beam to produce multiple sideband signals and a single pump beam to produce multiple pump beams.