Abstract: Exemplary embodiments of some aspects of the invention provide an optical decoding device including: a splitting device having first, second, and third, terminals; a nonlinear element; and an attenuator, wherein the second and third terminals are associated with an optical loop including the attenuator and the nonlinear element, the nonlinear element being displaced from a mid-point of the optical loop, and wherein the decoding device is able to receive multiple encoded signals via the first terminal, to decode at least one of the encoded signals and to provide a decoded signal at the first terminal in response to the at least one encoded signal. Exemplary embodiments of further aspects of the invention provide an optical code responsive device for decoding optical encoded signals, codes, and/or symbols, for header processing, for header reading, for address decoding and/or for optical packet routing.

Abstract: A variable optical attenuator and a method of manufacturing thereof are described. First, a bottom cladding is formed on a substrate. A waveguide structure having a core region and an attenuation region is subsequently formed on the bottom cladding by photolithography. A top cladding is then formed on the bottom cladding and the waveguide structure, and an electrode is next disposed thereon and is aligned above the attenuation region of the waveguide structure. Further, the waveguide structure is composed of a sol-gel material, which is obtained by mixing a solution of metal alkoxide with a solution of organically modified Si-alkoxide and heating the same.

Abstract: A method for equalizing optical signal power in a group of optical signals transmitted through an optical switch in an optical transmission system. In one embodiment a group of optical signals is input into an optical switch having at least one movable mirror array with a plurality of reflectors formed thereon, the optical beam being directed onto a selected at least one reflector and wherein attenuating the optical beam is accomplished by controllably detuning at least one of the selected at least one reflector to attenuate the optical beam.

Abstract: The present invention relates to all optical choppers for shaping and reshaping. A chopper according to some embodiments of the invention may include a threshold device having an input terminal for receiving an optical input signal and an output terminal for emitting an optical output signal in response to a part of the input signal having intensity above a threshold level of the chopping device, wherein the output signal is narrower than the input signal. In other embodiments the device may include a first splitting device having at least first, second and third terminals, and at least one nonlinear element, wherein the second and third terminals form an optical loop including at least one nonlinear element displaced from the center of the optical loop, wherein the splitting device is arranged to receive an input signal for producing a first output signal that is narrower than the input signal. In further embodiments the optical loop includes at least one more attenuator.

Abstract: In one aspect of the invention, an apparatus operable to facilitate add/drop multiplexing of optical signals includes an input operable to receive an input optical signal and an added optical signal, the input operable to generate a first and a second copy of the input signal and a first and a second copy of the added signal. The apparatus further includes a plurality of at least substantially reflective surfaces, each operable to receive either the first signal copies or the second signal copies and to reflect the copies for ultimate combination at an output to form an output signal for transmission. At least one of the at least substantially reflective surfaces comprises a moveable mirror operable to change its position relative to the input to create a phase shift between the first and second signal copies so that either the input optical signal or the added optical signal is communicated as the output signal depending on the position of the at least one moveable mirror.

Abstract: The present invention relates to an actuator and optical attenuator using the actuator. The rotary-type comb-drive actuator includes a substrate, a movable electrode, a drive electrode, one or more vertical springs, one or more vertical spring anchors, a horizontal spring and a horizontal spring anchor. The movable electrode is arranged on a plane of the substrate to be movable in parallel to the substrate plane, and formed to have a predetermined length so as to have a comb-shaped electrode comprised of a plurality of fingers. The drive electrode is formed to have a length corresponding to that of the movable electrode, and formed to have a comb-shaped electrode that is comprised of a plurality of fingers and arranged to be interdigitated with the comb-shaped electrode of the movable electrode. The vertical springs are arranged in parallel to the substrate, and connected to be perpendicular to the movable electrode on both sides of a first end of the movable electrode.

Abstract: The present invention relates to a control method and device for an optical filter, and a primary object of the present invention is to achieve accurate tracking control of the optical filter. Disclosed herein is a control method for an optical filter including first and second optical filter units cascaded, each having an input and first and second outputs. The first output of the first optical filter unit is connected to the input of the second optical filter unit. First light output from the second output of the first optical filter unit is converted into a first electrical signal having a level corresponding to the power of the first light, and second light output from the second output of the second optical filter unit is converted into a second electrical signal having a level corresponding to the power of the second light. A control signal is generated according to the first and second electrical signals. Then, the first and second optical filter units are controlled according to the control signal.

Abstract: The present invention is to provide an optical waveguide capable of allowing a desired incident light to efficiently propagate towards the light emission side and to emit therefrom, and capable of preventing unnecessary incident light from propagating, and in providing a light source module and an optical information processing apparatus using the optical waveguide. The optical waveguide comprises a bonded member of a substrate, a core layer and cladding layers, configured to introduce an incident line coming into the core layer toward a light emission side thereof. A metal layer for preventing the incident light coming into the cladding layer from propagating to the light emission side is formed in a pattern intercepting a sectional plane of light transmission of said cladding layer.

Abstract: A method and apparatus for monitoring fiber optic communications involves providing a space between a first end of a first optical fiber and a second end of a second optical fiber. A reflector is movable between a retracted position and an active position. In the active position, the reflector is positioned in the path of an optical signal beam passing through the space between the first optical fiber and the second optical fiber to reflect a portion of the optical signal beam as a tap signal. The reflector is selectively moved between the retracted position and the active position. This enables the tap signal to be selectively turned off and on. It also enables the portion of the optical signal beam reflected to be selectively adjusted.

Abstract: An MEMS variable optical attenuator includes a substrate having a planar surface, a micro-electric actuator arranged on the planar surface of the substrate, a pair of coaxially aligned optical waveguides having a receiving end and a transmitting end, respectively, and an optical shutter movable to a predetermined position between the receiving end and the transmitting end of the optical waveguides, and driven by the micro-electric actuator. A surface layer is formed on the optical shutter, has reflectivity less than 80% so as to allow incident light beams to partially transmit thereinto, and further has a sufficient light extinction ratio, thereby extinguishing the partially transmitted light beams therein.

Abstract: A structured material is disclosed with magneto-gyrotropic characteristics including at least one continuous structurally-chiral material. The structured material has an electric permittivity and a magnetic permeability at least one of which varies within the structured material along a first direction in a repetitious fashion wherein a repetition unit includes a chiral component and is at least 25 nm in length. The structured material exhibits non-reciprocal electromagnetic wave propagation velocity characteristics along a second direction that includes a non-zero component along the first direction.

Abstract: There is provided an attenuator device having a simple configuration and capable of selecting an output of beam of an arbitrary wavelength range from a plurality of output ports. The attenuator device comprises: a plurality of output fibers (1-3 and 1-5) having an end surface serving as an output port; discarding optical fibers (1-2 and 1-4) having an end surface serving as a discarding port and each arranged adjacently to the output optical fiber; a diffraction grating (5) which diffracts an incident beam into various directions according to the wavelength thereof; and a micro mirror array (7) which adjusts the output direction of the diffracted beam for each of the wavelength ranges output from the diffraction grating (5). The micro mirror array (7) adjusts the output direction of the diffracted beam so that a part of the diffracted beam may be output to the output port while the rest being output to the discarding port.

Abstract: A DWDM add/drop system for use in optical communication system is disclosed. Using semiconductor fabrication techniques, a plurality of waveguide arrays and signal carriers are substantially symmetrically arranged about an optical axis of the system. Electrode heaters are provided proximate junctions created at the intersections of selected waveguides. Using the heaters, portions of optical signals may be redirected to other waveguides. In addition, the heaters may be used to attenuate or otherwise modify signals in the waveguides. The waveguide arrays are arranged such that a plurality of signal processing operations may be performed substantially simultaneously. In a preferred embodiment, the switches and waveguide arrays are coupled with a light focusing device and a dispersion apparatus to form a switched, combined multiplexer/demultiplexer having signal attenuation and modification capabilities.

Abstract: In order to supply the optical fiber for attenuating optical signal enable the attenuation amount to become flat in wide wavelength scope, simultaneously adding at least two kinds of dopants for attenuating optical signal over the core and the cladding of the optical fiber. Then, properly adjusting the kind and the concentration of dopants for manufacturing the optical fiber 1 for attenuating optical signal; simultaneously adding the dopant enabling the absorption of optical signal to increase with the wavelength become long and the dopant enabling the absorption of optical signal to decrease with the wavelength become long. As the dopant, it is desired to select at least two kinds of transitional metals from Co, Ni, Cr, V, Fe, Mn, Tb and Tm. Further, as the doped area, it is desired to dope the 6 times of the center portion of the core from the center of the core.

Abstract: An optical functioning component has a tubular housing with a front end side having substantially the same shape as that of a front end of a removable plug housing of an optical connector plug. A rear end side of the tubular housing has a shape configured for connection to the optical connector plug when the plug housing is removed from the optical connector plug. A ferrule is provided on the front end side of the tubular housing and has a mechanism capable of attenuating, cutting-off, reflecting or absorbing a specific wavelength of light. An optical connection sleeve is connected to an end of the ferrule. A frame supports the ferrule and the optical connection sleeve and is mounted in the tubular housing for undergoing axial movement therein by a preselected amount.

Abstract: The present invention is directed to Y-branch digital optical switching and optical attenuator devices, which enhance the security of optical communications channels in the event of an electrical power loss.

Abstract: In accordance with the teachings of the present invention, a fiber-optic cable attenuator is presented. An assembly is presented for encasing a cable and providing an airtight chamber around the fiber-optic cable. The fiber-optic cable is then deflected within the assembly to allow a reading of the deflection point by an Optical Time Domain Reflectometer (OTDR). In one embodiment, the fiber-optic cable is deflected with pressurized air. In another embodiment, the fiber-optic cable is deflected with indenters fitted through the airtight chamber. As a result, initial reference data and cable location may be obtained and found without damaging the cable (i.e., using splices and other disruptive means).

Abstract: An optical device is configured such that an insertion plate is held by a flat cantilever having electric wiring, and the flat magnet is placed in such a manner that the magnet faces a surface of the cantilever opposite to the other surface of the cantilever facing an optical waveguide, and that the current flowing through the electric wiring is controlled in this state so that the Lorentz force caused by the interaction between the current and the magnetic field displaces the cantilever to drive the insertion plate, and to insert or remove the insertion plate into or out of the slit provided in the optical waveguide to switch the optical path of signal light or to adjust the quantity of an optical beam.

Abstract: A variable optical attenuator comprises a portion of a waveguide through which optical energy can propagate having a side surface through which optical energy can be extracted; a layer of thermo sensitive material having controllable optical properties, covering the side surface of the portion; a helicoidal heating element wrapped around the waveguide and covering at least the layer. The helicoidal heating element can be used to control the optical properties of the material by inducing a thermal transfer profile on the material using the heat dissipation of the heater through the material; wherein a wave propagation in the waveguide is influenced by the optical properties of the material controlled by the heating element.

Abstract: A method of controllably attenuating a beam of light coupled into a port includes directing the beam of light against a mirror, and controlling an orientation of the mirror such that a predetermined fraction of the beam of light is coupled into the port. The predetermined fraction is less than a maximum fraction corresponding to optimal coupling of the beam of light into the port. The method may be implemented with a variable optical attenuator including a first port, a second port, a mirror located to direct light output by the first port to the second port, and a controller coupled to the mirror to align it such that the predetermined fraction of light is coupled into the second port. The method may also be implemented with an optical switch.

Abstract: Optical waveguide fiber having low water peak as well as optical waveguide fiber preforms and methods of making optical waveguide fiber preforms from which low water peak and/or low hydrogen aged attenuation optical waveguide fibers are formed, including optical waveguide fiber and preforms made via OVD. The fibers may be hydrogen resistant, i.e. exhibit low hydrogen aged attenuation. A low water peak, hydrogen resistant optical waveguide fiber is disclosed which exhibits an optical attenuation at a wavelength of about 1383 nm which is less than or equal to an optical attenuation exhibited at a wavelength of about 1310 nm.

Abstract: A method and apparatus are disclosed for operating an eVOA by modulating its attenuation. If an optical signal power is below a loss of signal (LOS) power threshold the eVOA attenuation is set to a maximum attenuation and then, periodically and quickly decreased and increased in steps while checking for the presence of optical signals above the LOS power threshold. The method is also used for operating a multiplicity of eVOAs while minimizing the risk of damage to optical network equipment.

Abstract: An optical coupling assembly having an optical receiver that exhibits extended dynamic range, and, more particularly, an optical receiver that is integrated with a Variable Optical Attenuator (VOA) to extend the dynamic range of the receiver.

Abstract: The invention provides a variable optical attenuator capable of adjusting the attenuation of an optical signal to obtain the optical signal having a controlled intensity. The variable optical attenuator includes a circular loop formed by winding an optical fiber by at least one turn. The circular loop of the optical fiber is mechanically transformed into an oval loop to change the curvature radius at the deflected part of the optical fiber so that the attenuation of the output light is adjusted.

Abstract: An optical device has first and second non-parallel optical paths, and a light reflecting surface. The reflecting surface may have a first and second planar portion. The first planar portion receives light from the first path to reflect the light toward the second path. The second planar portion may form an angle ?1 with the first planar portion. Angle ?1 satisfies a condition of 175°??<180° in either clockwise or counterclockwise rotation from the first planar portion.

Abstract: Forming a plurality of loops in an optical fiber around a spool adjacent to an exposed end face can suppress internal reflections from the exposed end face. The radius of the loops can attenuate light that is propagating to and from the end face by causing light to leak out of the optical fiber's core and into its cladding. The radius can be selected to control physical stress in the optical fiber and promote reliability. The radius and the number of loops can be selected to meet a return loss specification. The loops can be formed by coiling the optical fiber around a spool that includes a slot for holding the optical fiber until it is put into service.

Abstract: The present invention concerns a preform for an optical fiber, an optical fiber so obtained and methods for making the same. The fiber is characterized in that porous glass doped with at least one dopant is used. Resulting fibers can be used to make high attenuation fibers.

Abstract: Described are various optical, opto-electrical and electrical components and subsystems. Some embodiments include input and output waveguides supporting opposing facets separated by a gap. The degree to which the opposing facets are aligned with respect to one another controls the light intensity in the output waveguide. An active closed-loop control mechanism dynamically controls the extent of waveguide alignment to maintain a desired output intensity. In other embodiments, the path between opposing facets can be selectively blocked by a micro blade. Still other embodiments combine switching with optical power equalization for ease of integration.

Abstract: A compressive force is applied to a conventional air-spaced etalon filter to fine tune the thickness of the spacers to a precise and uniform optical length. The etalon is coupled to a housing device capable of adjusting the thickness of each spacer, thereby tuning the etalon to the desired filter wavelength. The resulting assembly is permanently set to the desired parameters for direct use in optical applications.

Abstract: A variable optical attenuator for optical communications comprises: a substrate on which a plurality of alignment grooves are patterned; an input optical fiber aligned in one of the alignment grooves and receiving an optical signal; a reflector formed on the substrate so as to move to change a path of an optical signal which has passed through the input optical fiber; an output optical fiber aligned in one of the alignment grooves and outputting an optical signal whose path has been changed; a first lens aligned in one of the alignment grooves between the input/output optical fibers and the reflector so as to collimate an optical signal in a direction perpendicular to the substrate; and a second lens patterned on the substrate between the input/output optical fibers and the reflector so as to collimate an optical signal in a direction horizontal to the substrate, thereby facilitating an assembly process, reducing an alignment error, and miniaturizing its entire size.

Abstract: An integrated device of the present invention comprises free-space optics, a bi-directional multiplexor/de-multiplexor, a diffractive light modulator, a beam splitter, an optical performance monitor, and a controller. The free-space optics collimate, transform and image optical signals including a range of component wavelength signals. The bi-directional multiplexor/de-multiplexor de-multiplexes a wavelength division multiplexed signal into the component wavelength signals and multiplexes equalized component wavelength signals into an equalized wavelength division multiplexed signal. The diffractive light modulator selectively equalizes each component wavelength signal. The beam splitter is optically coupled in free-space to the diffractive light modulator for receiving the equalized component wavelength signals and re-directing a representative portion of each of the equalized component wavelength signals.

Abstract: Method and apparatus of attenuating an optical signal without adding extra components is presented. The drive current of the optical signal source is set to meet a predetermined bandwidth requirement and exceed a predetermined amplitude requirement. An optical isolator that is used to prevent back-reflections from reaching the optical signal source is used to achieve the desired amount of attenuation. More specifically, the invention includes controlling the attenuation by tuning an angle ? between the transmission axis of a polarizer that is part of the optical isolator and the original polarization state of the optical signal. By increasing the angle ?, the amount of attenuation is increased; by decreasing the angle ?, the amount of attenuation is decreased. The invention allows continuous tuning of the angle ?.

Abstract: The invention provides a radiation sensor including a housing, an attenuator with at least one cavity for attenuating optical radiation, and a detector, as well as an optical attenuator including an attenuator body, an entrance with one multi-stage input opening or plural input openings, and means for transferring radiation inside of the attenuator body and then to a detector. The invention further provides methods for using the radiation sensor or the optical attenuator.

Abstract: A system and method are used for pulse to pulse dose control in an illumination system, used, for example, in a lithography or a maskless lithography machine. The system and method can be used to decrease effective laser pulse-to-pulse variability in lithographic lasers, allowing adequate dose control using a minimum number of pulses (e.g. as little as one pulse).

Abstract: An integrated optical-power adjustable WDM is provided, which has a plurality of channels, each channel having a first input port, a second output port and a third output port, the second output port of one channel being connected to the first output port of the next channel, the first port of each channel having a waveguide, the third port of each channel having a waveguide, each channel comprising a pair of collimating elements composed of a first collimating element and a second collimating element, a thin film filter and a tunable optical filter chip functioning as a variable optical attenuator, wherein the tunable optical filter chip is set between the thin film filter and the third output port for each channel, thereby the respective tunable optical filter chip is integrated into the corresponding internal optical path for each channel of WDM to achieve optical-power control for each channel of the WDM.

Abstract: The intensity of signals in optical networks can be controlled using a variable optical attenuator (VOA). The present invention is a VOA that is particularly well suited for optical networks, for example to provide channel-by-channel normalization of gain control of wavelength division multiplexed signals. The inventive VOA includes a waveguide having a cladding that includes an electro-optical material and electrodes that produce an electric field within the electro-optical material when a voltage difference is applied to the electrodes. The VOA also includes a layer that is parallel to the core of the waveguide and that optically couples to the core to receive light from the attenuated signal. A power meter receives light from the layer as an indication of the amount of light attenuated from the signal and for controlling the voltage to the electrodes.

Abstract: A system and method is provided for attenuating a light signal. One embodiment includes a method for causing optical attenuation in a waveguide, where the waveguide has an input port for receiving a light signal and an output port for output of an attenuated light signal. First, an electric field is generated in at least a portion of the waveguide, such that a first refractive index in that portion of the waveguide is changed to a second refractive index. Next, the light signal in the waveguide is directed from the input port to the output port through the electric field. And lastly, the light signal is attenuated as a function of the electric field. The light signal may be attenuated, for example, by changing the deflection angle, changing the beam collimation width or from emitting part of the light signal from the waveguide before the light signal reaches the output port.

Abstract: An attenuator for fiber optic cable has a device for receiving a length of the cable. A series of attenuation structures is defined on the device, the attenuation structures being located proximate to each other. Each of the attenuation structures is adapted to bend the cable through a corresponding arc to alter the path of the fiber optic cable so that a signal traveling through the fiber optic cable is attenuated. Additionally, the attenuation structures are individually accessible to select a desired amount of attenuation.

Abstract: A fiber optic attenuating element is formed of a thermoplastic polymer having (i) a refractive index in the range of between about 1.42 and 1.47 as measured at a temperature of 23° C. and a wavelength of 1550 nm, (ii) a glass transition temperature of at least 105° C., and (iii) an intrinsic loss of less than one dB/mm at 1310 and 1550 nm. In disclosed embodiments, the polymer includes at least one monomer including fluorinated moieties and, optionally, one or more additional monomers. A main body portion of the element has a first planar contact face on a first side and a second planar contact face on a second, opposite side. The contact faces are dimensioned to couple optically with first and second optical fibers when ends of the fibers are urged against the faces by parts of an attenuator device in which the element is mounted.

Abstract: A Switch/Variable Optical Attenuator (SVOA) includes a die including at least one 2×2 optical switch and a respective integral variable optical attenuator for each of the at least one 2×2 optical switch. Each of the at least one 2×2 optical switches includes an INPUT optical port, an OUTPUT optical port, an ADD optical port, and a DROP optical port. The INPUT optical port is connected to the OUTPUT optical port in one state of the switch, and the ADD optical port is connected to the OUTPUT optical port in a second state of the switch. A single air gap exists between the ports. The VOA is mounted on the die and is associated with the switch for selectively attenuating optical signals transiting the air gap from one port to another.

Abstract: Optical devices and methods for regulating optical channel signals with specified wavelengths are disclosed. According to one aspect of the present invention, a number of variable optical apparatuses are employed. Each of the variable optical apparatuses includes a first and a second optical channel module, both configured at a wavelength ?i. Each of the variable optical apparatuses further includes an optical regulator (i.e. a neutral density filter controlled by a stepper motor) coupled between the first and second optical channel modules. When signals with different wavelengths arrive, only the signal with the wavelength ?i will transmit through the first optical channel module and the rest are reflected off. The transmitted signal is regulated (i.e. attenuated or strengthened) accordingly by the optical regulator before transmitting through the second optical channel module. Hence, the signals with different wavelengths can be respectively regulated by one of the variable optical apparatuses.

Abstract: Optical systems are disclosed which include one or more components such as an optical multiplexer, an optical demultiplexer, and, an optical amplifier. An optical device is included in the optical system and is configured to communicate with the optical component(s). The optical device includes a substrate proximate to which is disposed a first waveguide array. A second waveguide array is also provided that is disposed proximate the substrate so that a portion of the second waveguide array intersects a portion of the first waveguide array at a predetermined angle, so that a junction is formed. An index of refraction associated with the junction can be varied so that desirable effects can be implemented concerning optical signals transmitted through the waveguides.

Abstract: A variable optical attenuator (VOA) for use in an optical fiber communication system has a substrate, a thermal gradient prism and a heating element deposited on the prism. Heat is applied to the thermal gradient prism through the heating element. An optical signal is input into the prism via an optical signal input source. The optical signal traveling through the prism may be deflected due to a thermal gradient of the prism. The deflected optical signal is output into an optical signal output carrying medium. An optical signal strength measuring apparatus may measure a parameter related to the strength of the optical signal output into the optical signal output carrying medium.

Abstract: A method of switching from a single input optical fiber to one or more output fibers comprising the steps of providing an input signal into the input optical fiber, splitting the input signal and the input optical fiber to form a plurality of optical fibers and a plurality of split input signals each of the optical fibers carrying a single one of the plurality of the split input signals, attenuating the plurality of the split input signals, amplifying at least one of the plurality of the split input signals with a laser activated amplifier to produce at least one output signal, and outputting the at least one amplified split input signals through corresponding at least one output fibers.

Abstract: First and second optical fibers are opposed to each other, between which first and second lenses constituting a lens system having an optical axis coincident with those of the optical fibers are arranged with a gap therebetween in the direction of the optical axis. The actuators, ect are used to move the first and second lenses with electrostatic forces, in opposite directions along the optical axes of the optical fibers by the same amount at the same time. Thereby, the spot size of the light incident on the optical fiber on the reception side is changed while maintaining the light propagating between the first optical fiber and the second optical fiber point-symmetric in mode field shape. This changes the coupling efficiency between the first optical fiber and the second optical fiber, allowing an adjustment in light power.

Abstract: A fiber optical attenuator utilizing the cut-off phenomenon for single mode propagation of an optical wave down a single mode fiber, comprising an element such as a pixelated liquid crystal element, capable of spatially changing the phase across the cross section of an input optical signal. Such a spatial phase change is equivalent to a change in the mode structure of the propagating wave. The signal propagating in the single mode output fiber is attenuated in accordance with the extent to which higher order modes are mixed into the low order mode originally present. When the mode is completely transformed to higher order modes, the wave is effectively completely blocked from entering the output single-mode fiber, and the attenuation is high. The level of attenuation is determined by the fraction of the wave which is converted to modes other than the lowest order mode, and is thus controllable by the voltage applied to the pixels of the liquid crystal element.

Abstract: In accordance with the teachings of the present invention, a fiber-optic cable attenuator is presented. An assembly is presented for encasing a cable and providing an airtight chamber around the fiber-optic cable. The fiber-optic cable is then deflected within the assembly to allow a reading of the deflection point by an Optical Time Domain Reflectometer (OTDR). In one embodiment, the fiber-optic cable is deflected with pressurized air. In another embodiment, the fiber-optic cable is deflected with indenters fitted through the airtight chamber. As a result, initial reference data and cable location may be obtained and found without damaging the cable (i.e., using splices and other disruptive means).

Abstract: A system and method for operating a plurality of eVOAs in an optical network is provided. The system comprises a number of eVOAs, each eVOA coupled to one or more optical taps and connected to a microcontroller. The microcontroller comprises a monitor signal processing controller for measuring the power of the optical signal at the eVOAs; a scheduler for continuously cycling and checking the eVOAs operating attenuations; a microprocessing controller for determining, setting, adjusting and updating the eVOA operating attenuation and a means for communications between the microprocessor and the other controller within the system. The microcontroller cycles through the plurality of eVOAs and controls one eVOA at a time according to a predetermined method of the eVOA operation. Individual eVOAs may be controlled according to the same or different methods of controlling operations thereof as required.

Abstract: An optical AND logic gate includes a summing gate having first and second inputs for receiving first and second optical signals, and a threshold device. The gate produces an output corresponding to the AND product of the first and second optical signals. In another version the AND gate includes first and second inputs for receiving first and second optical signals, and an optical loop for producing an output corresponding to the AND product of the first and second optical signals. In an alternative versions a NAND gate is provided by applying an optical logic NOT on an AND gate.

Abstract: An optical channel regulator (46) is provided. The optical channel regulator (46) includes a tapped optical coupler (60) receiving an optical line carrying an optical signal. The tapped optical coupler (60) provides substantially all of the optical signal as an output. An electrically variable optical attenuator (64) receives the output of the tapped optical coupler (60) and attenuates the optical signal responsive to a feedback control signal. A second tapped optical coupler (66) receives an output of the attenuator (64). The second coupler (66) provides substantially all of the received optical signal as an output and provides a remaining portion of the optical signal as a tapped output. An optical detector (68) then receives the tapped output and provides an output signal representing the optical signal. A comparator (70) receives the output signal of the optical detector (68) and a reference signal.