Abstract: A hybrid and tapered waveguide coupler that has two different single-mode waveguide sections for light at two different wavelengths to couple light at the two different wavelengths into or out of an optical device located in a reach of an evanescent field of the guided optical energy in the waveguide coupler.

Abstract: Disclosed is the use of a polymer material in an optical waveguide structure. The polymer material may be used in either the cladding or the core material of an optical waveguide. The use of polymer material as such is advantageous in that the index of refraction of polymer material varies significantly with changing temperature. The polymer material is subjected to a heating mechanism and/or a cooling mechanism to manipulate the index of refraction as desired.

Abstract: A dynamic gain flattening filter includes a first filter stage. The first filter stage has a first tunable coupling member and a first differential delay with first and second tunable delay paths. The first tunable coupling member adjusts an amount of power of the optical signal that is divided onto the first and second tunable delay paths of the first differential delay.

Abstract: An all-fiber Mach-Zehnder interferometer has a central fiber structure in which two single-mode fibers are placed to have a desired path difference and are stabilized in such position by bonding them in certain spots. A coupler is then made on each side of the central fiber structure to produce the Mach-Zehnder effect. The combination of the central fiber structure and of the couplers at each end is mounted on a substrate and packaged to produce the interferometer.

Abstract: The present invention relates to an optical waveguide coupler device. As shown in FIG. 1, the optical waveguide coupler device 8 comprises two optical waveguide cores 2, 3 formed on the surface of a substrate 1. The optical waveguide cores 2, 3 are covered by lower and upper cladding layers 6, 7 both formed on the substrate 1; and the two optical waveguide cores 2, 3 are brought close to and in parallel with each other at two sites to form two directional couplers 4, 5 there. The cross-section and refractive index of each of the optical waveguide cores 2, 3 and the parameters of other elements of the circuit are optimized such that an optical signal is reliably routed by the circuit without undergoing a wavelength shift even when the circuit is exposed to the changes of ambient temperature.

Abstract: A 2 to n divider with integrated optics, where n is an integer greater than or equal to 2, including at least one 2 to 2 optical divider element in a substrate. The optical divider element comprises a first and a second guide with widths equal to W1 and W2, respectively. The first and second guides are suitable for dividing an input light wave input into one of the guides, into a first and second output wave transported by the first and second guides respectively according to a determined division ratio. These first and second guides have at least three parts. A first part where the first and second guides move toward each other, a second part where the first and second guides are approximately parallel to each other and a third part where the first and second guides gradually separate from each other.

Abstract: A differential phase shift keyed demodulator system uses a Michelson interferometer configuration in which polarization maintenance is accomplished by using a single 50:50 coupler coupled to a first Faraday rotator mirror and a second Faraday rotator mirror through a first fiber and a second fiber, respectively. In this way, system passively eliminates the polarization problem caused by using a Mach-Zehnder interferometer.

Abstract: This invention describes new developments in Sagnac Raman amplifiers and cascade lasers to improve their performance. The Raman amplifier bandwidth is broadened by using a broadband pump or by combining a cladding-pumped fiber laser with the Sagnac Raman cavity. The broader bandwidth is also obtained by eliminating the need for polarization controllers in the Sagnac cavity by using an all polarization maintaining configuration, or at least using loop mirrors that maintain polarization. The polarization maintaining cavities have the added benefit of being environmentally stable and appropriate for turn-key operation. The noise arising from sources such as double Rayleigh scattering is reduced by using the Sagnac cavity in combination with a polarization diversity pumping scheme, where the pump is split along two axes of the fiber. This also leads to gain for the signal that is independent of the signal polarization.

Abstract: An optical waveguide element having a directional coupler is disclosed. The element includes a first and a second waveguide located adjacent to each other at a predetermined portion for mode coupling, a first dummy waveguide extending from an one end of the second waveguide, a reflector installed on an end surface of the first dummy waveguide, and a second dummy waveguide located adjacent to the first dummy waveguide at a predetermined portion for a mode coupling. The optical signals progressing from the second dummy waveguide to the first dummy waveguide disappear while sequentially passing through the reflector and the second dummy waveguide. In the optical waveguide element, optical signals passing through the first dummy waveguide gradually disappear while passing through the reflector and the second dummy waveguide, thereby improving a bi-directional cross-talk.

Abstract: An apparatus for optically coupling a light source with a light-receiving end face of an optical waveguide comprises a lens for focusing a light beam emitted from the light source at a focal point on the light-receiving end face of the optical waveguide. An adaptive coupler, positioned in the optical path, is responsive to a beam steering control signal for steering and aligning the focal point relative to the light-receiving end face of the optical waveguide. In one form, the adaptive coupler comprises a pair of transparent substrates having confronting, parallel inner faces, the inner face of one of the pair of substrates carrying a beam intercepting, optically transparent, constant potential electrode and the inner face of the other of the pair of substrates carrying an electrically resistive, beam intercepting, optically transparent film. A pair of spaced apart electrodes in electrical contact with the film apply a linear voltage gradient along the film.

Abstract: A planar light wave circuit may include a directional coupler with two waveguides come close to one another in a so-called gap region. Polarization dependent coupling may be reduced by forming trenches on either side of the gap region to reduce birefringence.

Abstract: An interferometer includes a waveguide core, and thin film heaters with widths W1 and W2. The thin film heaters are mounted directly above the waveguide core, and operate as two types of different annealing regions. The annealing, which is carried out by supplying current to the thin film heaters, can alter the quality of the cladding, and change the stress applied on the waveguide core, thereby making it possible to control the polarization dependency. Thus changing the width of the thin film heaters and/or the amount of the supply current thereto enables the permanent control of the effective refractive index (birefringence index) independently in the transverse electric polarization mode and the transverse magnetic polarization mode. This enables the transverse electric polarization mode to be adjusted to a phase difference of &lgr;/2, and the transverse magnetic polarization mode to a phase difference of zero.

Abstract: A grating, suitable for filtering optical radiation, comprises a plurality of concatenated grating sections each having different physical characteristics as compared with adjacent grating sections. At least one of the sections comprises a waveguide structure formed by a thin strip (100) of a material having a relatively high free charge carrier density surrounded by material having a relatively low free charge carrier density. The strip has finite width (W) and thickness (t) with dimensions such that optical radiation having a wavelength in a predetermined range couples to the strip and propagates along the length of the strip as a plasmon-polariton wave. Various grating architectures may be implemented, e.g. chirped, interleaved, uniform, etc. A method of producing such gratings derives normalized phase constants and attenuation constants and then uses, for example, TMM or Coupled Mode Theory to derive therefrom the optical response of the grating.

Abstract: Optical systems of the present invention generally include at least one optical amplifier having a first pump source configured to supply power to said amplifier via a first pumping paths. A second pumping path is provided to supply power to the amplifier from a second pump source configured to replace power from the first pump source. The amplifier allows the replacement and repair of a pump source during operation by providing in-service hot swap capability, which increases the overall availability of the amplifier. The pump source can also be changed during operation to allow reconfiguration of the optical system.

Abstract: A tunealble optical grid-assisted add/drop filter for codirectional operational mode consisting of at least two waveguides composed of two different classes of material of different optical parameters. The thermal refractive index coefficient dn/dT, the electro-optic coefficient dn/dE or the dispersion dn/d&lgr; of the two materials differ from each other such that when the temperature, the electric field or the wavelength of or in the two waveguides is change, the result will be effects of different powers.

Abstract: The invention provides a wavelength division demultiplexing apparatus which can reduce the connection loss between an input slab and channel waveguides and can suppress excitation of higher-order mode light to reduce the loss. The apparatus includes a first waveguide for propagating WDM light, a first slab for diffusing the light from the first waveguide, a plurality of channel waveguides having a series of different waveguide lengths with a predetermined difference for receiving and splitting the light from the first slab, a second slab for condensing the split light from the channel waveguides, and a second waveguide for propagating the light from the second slab therein, all formed on a subtrate. The channel waveguides and the first slab are optically connected to each other at a number of nodes greater than the number of nodes at which the channel waveguides and the second slab are connected to each other.

Abstract: A Mach-Zehnder interferometer optical switch and a Mach-Zehnder interferometer temperature sensor include two optical waveguides having refractive index temperature coefficients with opposite signs, the two optical waveguides being in the vicinity of each other at two locations such that two directional couplers are provided at the two locations and including respective optical waveguide arms between the two directional couplers.

Abstract: An integrated photonic apparatus that includes a glass substrate having a major surface, a first waveguide segment and a second waveguide segment, and a folded evanescent coupler connecting the first waveguide segment to the second. The folded evanescent coupler is formed by a first length of the first waveguide segment and an equivalent length portion of the second waveguide running parallel and adjacent to the first waveguide segment. The first length is substantially equal to one half of an evanescent-coupler length needed to transfer a first wavelength in a non-folded evanescent coupler. A reflector (e.g., dielectric mirror that is highly reflective to light of the first wavelength and also highly transmissive to light of a second wavelength) is located at an end of the folded evanescent coupler. The first length is selected to transfer substantially all light of a first wavelength.

Abstract: This invention discloses an optical device that includes a wavelength-selective optical transmission system. The wavelength-selective optical transmission system further includes a first waveguide for transmitting a multiplexed optical signal therethrough. The wavelength-selective optical transmission system further includes a second waveguide coupled to the first waveguide wherein a least one of the first and second waveguides having a set of wavelength-selective Bragg gratings disposed near a coupling section between the first and second waveguides. One of the first and second waveguides has an aspect ratio, i.e., a ratio of a thickness divided by a width, is no greater than 0.75.

Abstract: A method of measuring a power spectrum of an optical signal. The optical signal is transmitted through an optical fiber. A power of at least one wavelength of the optical signal is coupled from a first mode to a second mode of the waveguide. The power of the optical signal coupled from the first mode to the second mode is measured at a detector.

Abstract: An optical device including a microstructured fiber pumped by an external pulsed-light source. In one embodiment, the microstructured fiber includes two waist regions functioning as a tunable attenuator and a wavelength shifter, respectively. Output wavelength of the optical device is selected by attenuating the pump light in the first waist region and then passing the light through the second waist region to shift the pump energy to a new spectral band. An optical device of the invention configured with two or more microstructured fibers generates two or more synchronized pulsed beams, each at a different characteristic wavelength. Certain embodiments of the invention provide an inexpensive, compact, energy-efficient multi-wavelength synchronized pulsed-light source.

Abstract: An optical threshold device including an optical loop having first and second terminals aid including at least one non-linear optical element and at least one optical attenuator; and an optical coupler able to couple a first portion of an input signal to the first terminal and a second portion of the input signal to the second terminal, wherein the optical loop is able to produce a first return signal at the second terminal and a second return signal at the first terminal, and wherein the optical coupler is able to combine the first and second return signals into an output signal.

Abstract: Optical modulators are provided. A representative optical modulator includes an optical medium that is adapted to propagate optical signals. An array of lattice sites are arranged in the optical medium, with at least some of the lattice sites exhibiting lower refractive indexes than the refractive index of the optical medium. Preferably, a first of the lattice sites incorporates a first optical component that is moveable relative to the optical medium. By moving the first optical component relative to the optical medium, a propagation characteristic of the optical medium can be altered. Optical systems, methods and other optical modulators also are provided.

Abstract: An optical modulation apparatus includes an optical signal input section, an optical signal propagation path, an optical modulator that modulates the phase of optical signals in at least two of a plurality of optical paths, and a wavelength selective filter that selectively reflects and transmits. Optical signals input via the input section are divided into a plurality of optical paths at a branching point and phase modulated by the phase modulator, that divides the optical path into a plurality of optical paths. Light transmitted by the filter is output via the output section, while light reflected by the filter travels back along the optical path and is again phase modulated by the phase modulator combined at the branching point and output from the input section as an intensity modulated optical signal.

Abstract: An optoreflective structure for reflecting an optical signal following a path defined by an optical waveguide comprising a first cladding layer having a first planar cladding surface; a waveguide disposed on the first cladding layer; and a second cladding layer disposed on the waveguide and having a second planar cladding surface. The first cladding layer, the second cladding layer and the waveguide terminate in a generally dove-tailed structure having a beveled planar surface. An optoreflector is disposed on the beveled planar surface for a changing direction of an optical signal passing through the waveguide. Methods of producing the optoreflective structure are disclosed.

Abstract: A coupling method of a coupler includes the following steps: (1) making a pair of optical fibers with different photosensitivity fused and drawn, (2) irradiating specific portions of the pair of optical fibers by intense ultraviolet light at the same time for making refractive index of the pair of optical fibers markedly different, (3) supervising coupling light energy loss spectrum and gradually adjusting the intense ultraviolet light for decreasing maximum coupling ratio and achieving an optical fiber coupler of optimum flat spectrum, thereby improving fabricating process and reducing deficient products.

Abstract: The present invention introduces a novel and simple method to adjust the MZ filter channels to those of the ITU grid. This is done through inducing an optical path length difference by using a UV light source to create a change in the index of refraction of the fiber arms after the device is packaged. The UV light is launched into the MZI filter through one of its input ports in order to achieve the phase adjustment. Since the exposure length is the entire length of one of the arms of the MZI, the required refractive index change is much smaller than the localized UV tuning of the previous methods. This allows for a weaker UV source power and shorter treatment times, thus reducing the chances of localized fiber damage.

Abstract: The abstract is amended to read, “An inventive method and apparatus is provided by a bidirectional optical 1×2 device formed by a cascade of three optical 2×2 devices. Each 2×2 device is bidirectional where optical signals propagate through the 2×2 device in the forward and backward directions simultaneously. The demultiplexing and multiplexing occur simultaneously to thereby perform bidirectional 1×2 optical demultiplexing and 2×1 optical multiplexing in the 1×2 device.

Abstract: A wavelength division multiplexing (WDM) switching includes one or more optical add/drop multiplexers (OADMs) to drop or add optical signals on one or more optical channels. The OADM may be a 1-channel OADM which includes first and second conductors arranged periodically so as to have a pair of different polarities, an optical waveguide type coupler dropping or adding an optical signal of a specific channel by an electric field generated from the first and second conductors, a power supply unit supplying the second conductor with a power, and a switch placed between the second conductor and power supply unit to control a power supply of the second conductor, so as to control generation and termination of the electric field in accordance with an operation control signal.

Abstract: An electrical insulation device for bidirectional connecting lines is proposed which operates reliably at high frequencies and can be integrated easily on a chip. In accordance with a first embodiment, for the purpose of electrical isolation, two separate optocouplers are provided per bidirectional connecting line. A control unit evaluates the control signals which are output by one of the two circuit units, and thereupon activates one of the two optocouplers while the other optocoupler is simultaneously deactivated, in order, in this way, to allow transmission of signals via the associated connecting line in one direction. In a second embodiment of the invention, only a single optocoupler is provided per bidirectional connecting line.

Abstract: A system capable of creating multiple beams of light using laterally coupled waveguides. Each beam is of a different central wavelength, capable of being generated on chip and coupled into a single fiber, and emitted from a single outcoupling grating (OCG). The present innovations can be used to create a multiple wavelength source generating multiple signals of different wavelengths simultaneously. The present innovations can also function as a tunable laser source system, capable of generating one of many different wavelength signals at a time. Waveguides are laterally coupled through, for example, evanescent coupling. The degree of coupling is controlled by varying the voltage applied to contacts attached to the waveguides at the coupling region.

Abstract: An optical power splitter may include an optical amplifier and a combiner to combine pump laser power with an input optical signal. The combined signal is then split. The split signal may then be passed to a waveguide amplifier.

Abstract: Interference caused by the propagation of a transmit signal transmitted from a transmit antenna to a receive antenna is effectively cancelled by an improved signal cancellation system. The system includes an interference cancellation signal generator that generates a time-delayed and amplitude-reduced representation of said transmit signal. A summing stage is operably coupled to the interference cancellation signal generator and the receive antenna. The summing stage subtracts the time-delayed and amplitude-reduced representation of the transmit signal from a receive signal to substantially cancel the interference. The interference cancellation signal generator preferably includes a novel programmable optical delay line that introduces a variable amount of optical delay to an optical signal derived from said transmit signal in addition to a thyristor-based sigma delta modulator that converts samples of the transmit signal to into a digital signal in the optical domain.

Abstract: An optical communications system, including first terminal equipment, second terminal equipment, third terminal equipment, a first powered optical segment connected to the first terminal equipment and including at least one amplifier, a second powered optical segment connected to the second terminal equipment and including at least one amplifier, an unpowered optical segment connected to the third terminal equipment, and a branch unit connecting the first powered segment, the second powered segment, and the unpowered segment via passive, all-optical connections, and wherein the unpowered segment is pumped with optical energy through the branch unit from at least one of the amplifiers in the first and second powered segments.

Abstract: A connector to an optical fiber comprises a prism, a ferrule and an aspheric lens. The prism includes a triangular wedge element having a first surface, a second surface and a base. The ferrule guides the optical fiber so as to contact the optical fiber with the first surface of the prism. The aspheric lens is integrated on the second surface, the integrated aspheric lens being positioned so that the prism serves to redirect a light beam at an angle relative to an axis of the optical source input through total internal reflection by utilizing the base of the triangle wedge element. The aspheric lens serves to collimate the redirected light beam or focus the light beam before being redirected. This arrangement may, for example, be used within a WDM system to multiplex and de-multiplex several wavelengths of light, using a “zig-zag” optical path configuration and thin film filters to separate the wavelengths.

Abstract: In accordance with the invention, the optical power level in an optical waveguide is monitored by enclosing a length of the waveguide within an insulated cavity of comparable length and cross section, measuring a first temperature T1 within the cavity, measuring a second temperature T2 outside the cavity and deriving from the difference, T1−T2, a measure of the optical power level. Exemplary apparatus for monitoring the optical power level in an optical waveguide comprises a substrate with an insulated groove for receiving an optical fiber, an insulated lid for sealing the fiber within the groove, and internal and external temperature sensors.

Abstract: An apparatus for interfacing optical signals to an optical fiber has a layered interface element with a first electrically conductive layer defining a first surface, a photoactive material layer in intimate contact with the first layer on a second surface opposite the first surface, a second electrically conductive layer in intimate contact with the photoactive material layer, confining the photoactive material layer between the first and second electrically conductive layers, and a third surface angularly disposed to the first surface and intersecting the photoactive material layer; and a pressure element having a contact surface translatable toward the first surface of the interface element, to urge an optical fiber positioned across the interface element into the first surface, and by local deformation of the optical fiber also into the third surface, creating thereby an intimate contact region between an edge of the photoactive layer intersecting the third surface and the optical fiber.

Abstract: A method for producing fiber optic devices having improved intrinsic resistance to external environmental conditions and a fiber optic device made my the method are disclosed. The fabrication method produces an optic device that is treated with deuterium. The method includes a step for treating and/or making optical devices in the presence of a flame produced by the combustion of deuterium gas or a mixture including deuterium.

Abstract: Optical apparatus for combining and splitting optical signals using folded waveguides and method for making the same are disclosed. According to one aspect of the present invention, at least one waveguide used in the optical apparatus is folded around according to a predefined curve to couple to other waveguides. The predefined curve is so designed as to minimize possible insertion loss as a result of such folding of the waveguide. The proper folding of the waveguide leads to modified designs of the optical devices with all the ports on one side so as to simplify the alignment procedures afterward. In addition, the optical device according to the present invention has much smaller footprint and makes it possible to increase higher yield from fabricating substrate material on which the waveguides are formed.

Abstract: Planar wave guide devices deposited by reactive pulsed dc sputtering processes are presented. Devices according to the present invention include a waveguide with a core sputter deposited onto a substrate and a cladding sputter deposited onto the core. In some embodiments, second waveguide can be deposited in close proximity to the first waveguide to form a direction coupler. In some embodiments, light traveling through the waveguide can be amplified or attenuated in response to signals applied to the waveguide. In some embodiments, a DWDM device is formed in the waveguide. In other devices, a mode-locked laser is formed.

Abstract: An optical multiplexer/demultiplexer includes first and second directional coupling portions in which first and second optical waveguides are provided to transfer a light between the first and second optical waveguides. Lengths of the first and second optical waveguides have a difference (&Dgr;L). A product between the difference (&Dgr;L) and a refractive index (n) of the first and second optical waveguides approximates a product between a cross-propagation wavelength (&lgr;2) and a value (N′) substantially equal to an integer (N), and a product between a through-propagation wavelength (&lgr;1) and the value (N′)±0.5. Power coupling ratio differences are at least approximately 1% and at most approximately 10%. Third power coupling ratios with respect to an average wavelength of the cross-propagation wavelength (&lgr;2) and the through-propagation wavelength (&lgr;1) are at least approximately 45% and at most approximately 55%.

Abstract: It is an object of the present invention to provide an optical filter which allows parameters to be easily adjusted, which allows birefringence and temperature dependence to be easily compensated for, and which is essentially free from dispersion. The optical filter includes an optical coupler that splits light into two beams, optical couplers connected to outputs of the optical coupler, a first group of two optical waveguide delay lines connected to the coupler, a second group of two optical waveguide delay lines connected to the coupler, an optical coupler that combines lights from the first group of the lines, an optical coupler that combines lights from the second group of the lines, and a multimode interference optical coupler that combines lights from the couplers together.

Abstract: A wavelength-selective cross connect switch is disclosed that can selectively pass a multi-wavelength incoming signal received on a given incoming port to a corresponding output port in a bar state; or cross the received signal to an opposite output port in a cross state, using only two wavelength blockers and a number of optical circulators. Power splitters divide the power of each incoming signal in half and the half-power signals are applied to the two wavelength blockers surrounded by corresponding optical circulators. Each of the wavelength blockers control either the bar state or the cross state. The outputs of the two wavelength blockers are combined to produce an output signal at each of the output ports. Thus, the wavelength-selective cross connect can selectively pass or cross an incoming signal to an appropriate output port, as desired. The disclosed wavelength-selective cross connects can be serviced without interrupting traffic.

Abstract: The present invention relates to an optical waveguide coupler device. As shown in FIG. 1, the optical waveguide coupler device 8 comprises two optical waveguide cores 2, 3 formed on the surface of a substrate 1. The optical waveguide cores 2, 3 are covered by lower and upper cladding layers 6, 7 both formed on the substrate 1; and the two optical waveguide cores 2, 3 are brought close to and in parallel with each other at two sites to form two directional couplers 4, 5 there. The cross-section and refractive index of each of the optical waveguide cores 2, 3 and the parameters of other elements of the circuit are optimized such that an optical signal is reliably routed by the circuit without undergoing a wavelength shift even when the circuit is exposed to the changes of polarization and ambient temperature.

Abstract: A two-way optical communication module is provided with: a first optical wave-guide including a light emitting element 2 for emitting a light with wavelength &lgr;1, a curved wave-guide portion (optical wave-guide 6) coupled to the light emitting element 2, and a straight wave-guide portion (optical wave-guide 8) coupled to a core 11 of an optical fiber 4; a second optical wave-guide including a light receiving element 3, a curved wave-guide portion (optical wave-guide 7) coupled to the light receiving element 3, and a straight wave-guide portion (optical wave-guide 9) coupled to a clad 12 of the optical fiber 4; and a directional optical coupler 10 which includes the optical wave-guides 8 and 9 and which guides the light with wavelength &lgr;1 from the optical wave-guide 6 to the core 11 and the light with wavelength &lgr;2 from the core 11 to the optical wave-guide 7.

Abstract: Two right and left optical waveguides are provided so as to pass through a first directional coupler, a phase shifter, and a second directional coupler and so that directional couplers are provided in the first directional coupler portion and the second directional coupler portion. A third electrode is provided between these optical waveguides. A first electrode is provided on the left side of the left optical waveguide, and a second electrode is provided on the right side of the right optical waveguide. These electrodes are extended into the first directional coupler. Upon the application of a bias voltage, the voltage is simultaneously applied to all the first to third electrodes. By virtue of this construction, a waveguide-type optical control device can be realized which, in a directional coupler-type Mach-Zehnder (MZ) construction, can improve the extinction ratio without the complication of the construction.

Abstract: An optical communications system comprises, among other things, a laser source; an optical waveguide interconnected to the laser source to carry an optical signal from the source to an optical receiver; an optical receiver interconnected to the optical waveguide for decoding the signal; and a mechanical modulator adapted to substantially continuously mechanically perturb a portion of the optical waveguide so as to reduce Rayleigh backscattering from the optical waveguide.

Abstract: A fused optical coupler comprising a polarization maintaining fiber and a standard fiber is provided. The cross-section of the said standard fiber is smaller than the cross-section of the polarization maintaining fiber in the area of fusion of the coupler. The internal forces in the coupling area are sufficiently low to provide an extinction ratio of more than 20 dB at the output of the polarization maintaining fiber.

Abstract: A multistage Mach-Zehnder interferometer type optical circuit including any number of symmetrical Mach-Zehnder interferometers and any number of asymmetrical Mach-Zehnder interferometers connected in cascade. In the optical circuit, low coherence light is used first to obtain individual phase control conditions of the symmetrical Mach-Zehnder interferometers without being affected by the asymmetrical Mach-Zehnder interferometers. Second, phase control conditions of the individual asymmetrical Mach-Zehnder interferometers are obtained by controlling the symmetrical Mach-Zehnder interferometers based on the first phase control conditions.

Abstract: A pump assembly for an optical amplifier includes a plurality of pump radiation sources, each pump radiation source producing radiation at a respective one of a first number of pump wavelengths. A coupler is optically coupled to each of the plurality of pump radiation sources, receives each of the first number of pump wavelengths from the plurality of pump radiation sources, and outputs each of the first number of pump wavelengths to each one of a second number of outputs. The pump assembly also includes a plurality of pump signal combiners, each pump signal combiner optically coupled to a respective one of the second number of outputs of the coupler and receiving each of the first number of pump wavelengths output from the coupler. Each pump signal combiner placing each of the first number of pump wavelengths output from the coupler in co-propagation with a respective one of a plurality of data signals propagating on a respective one of a plurality of optical fibers.