Abstract: Disclosed herein is a method of transmitting a data stream from a first location to a second location through an optical network, as well as a corresponding performance monitoring unit, a transmitting arrangement and a receiving arrangement.

Abstract: In the examples provided herein, a data center transmission system includes a VCSEL (vertical-cavity surface-emitting laser) that lases in a single spatial mode with a side mode suppression ratio of at least 25 dB, where the VCSEL is formed on a substrate and lases at a wavelength transparent to the substrate, and further where an output of the VCSEL exits through the substrate. Also, the VCSEL is directly modulated. The system further includes an optical fiber having a first end to receive the output of the VCSEL for propagation along the optical fiber. The optical fiber supports a single spatial mode without supporting higher order spatial modes over a range of wavelengths between 1260 nm and 1360 nm. The system also includes a receiver to receive the directly modulated output of the VCSEL after propagation through the optical fiber.

Abstract: A cable arrangement includes indexed optical lines that are indexed between first and second multi-fiber connectors; a first of the optical line having a first end terminated at the first multi-fiber connector; and a second optical line having a first end terminated at the second multi-fiber. An input of an optical splitter is optically coupled to second ends of the first and second optical lines. The optical splitter splits optical signals carried over the first and second optical lines onto output lines so that each output line carries signals split from the first optical line and signals split from the second optical line.

Abstract: Systems and methods for optical communication using single source optical transmission are disclosed. A representative method includes receiving optical signals at a first frequency by a receiver (RX) from an optical fiber. The received optical signals are routed to a modulator that modulates the optical signals at a second frequency. The optical signals are emitted by a transmitter (TX) back to the optical fiber at the second frequency.

Abstract: An optical system architecture includes indexed optical lines that are indexed between first and second multi-fiber connectors; a first of the optical line having a first end terminated at the first multi-fiber connector; and a second optical line having a first end terminated at the second multi-fiber. An input of an optical splitter is optically coupled to second ends of the first and second optical lines. The optical splitter splits optical signals carried over the first and second optical lines onto output lines so that each output line carries signals split from the first optical line and signals split from the second optical line.

Abstract: An optical network unit (ONU) is installed to communicate with an optical line terminal (OLT) located at a remote terminal (RT). The ONU includes a first subscriber downlink interface to serve a first subscriber premises and a second subscriber downlink interface to serve a second subscriber premises. The RT is located apart from a central office (CO) and in communication with the CO. A first removably attachable subscriber downlink module is communicatively coupled to the first subscriber downlink interface. A second removably attachable subscriber downlink module is communicatively coupled to the second subscriber downlink interface. The first removably attachable subscriber downlink module is replaced with a third removably attachable subscriber downlink module.

Abstract: A method, apparatus, and system for network monitoring, and more specifically for correlating downstream devices in an optical network with downstream ports of an optical splitter through which they are communicating with a central office. The downstream devices operational on the network are indentified and listed in a correlation table. Selected subsets of these devices are then monitored, preferably by an ISM under the direction of a management node, in a series of monitoring cycles until a satisfactory correlation may be achieved. The correlation cycle may be performed at startup, as needed, or on a periodic basis.

Abstract: A method for testing the operation of an optical fiber cable in a communication network using an optical time domain reflectometer (OTDR) instrument includes receiving a range of identifiers of fiber sets to be tested. Identifiers of a first fiber set are displayed. The first fiber set is included in the range and constitutes a next fiber set to be tested. A determination is made whether the first fiber set is connected to the OTDR instrument. In response to determining that the first fiber set is connected to the OTDR instrument, a test of the first fiber set is performed using the OTDR instrument. Identifiers of a second fiber set are displayed. The second fiber set is included in the range and constitutes a next fiber set to be tested.

Abstract: The present wavelength multiplexed optical system includes a multimode optical fiber that transmits wavelength multiplexed optical signals and a plurality of multimode modal dispersion compensation optical fibers. Each modal dispersion compensation optical fiber can transmit one of the multiplex wavelengths, and each modal dispersion compensation optical fiber has an optimized index profile such that the modal dispersion for the transmitted wavelength is approximately inversely equal to the modal dispersion induced in the multimode optical fiber. The wavelength multiplexed optical system facilitates an increased bitrate without reducing bandwidth.

Abstract: A bi-directional optical transceiver includes multiple single mode optical ports and a multi-mode optical port. A multi-mode optical combiner combines single mode optical signals received at the single mode optical ports into a multi-mode optical signal at the multi-mode optical port. Each single mode optical signal having a distinct optical mode that does not interfere with the optical mode of the other single mode optical signals. A photo detector coupled to the multi-mode optical combiner detects a total optical power of the single mode optical signals in the multi-mode optical signal.

Abstract: An optical transport system has an optical transmitter and an optical receiver coupled to one another via an optical link having a plurality of transmission paths. The optical transmitter uses at least one of the transmission paths to transmit an optical-reference signal that enables the optical receiver to obtain (i) an optical local-oscillator signal that is phase- and frequency-locked to an optical-carrier frequency used by the transmitter for the generation of data-bearing optical signals and (ii) a clock signal that is phase- and frequency-locked to the clock signal used by the transmitter. The optical receiver then uses these signals to demodulate and decode the data-bearing optical signals in a manner that significantly reduces the complexity of digital signal processing compared to that in a comparably performing prior-art system.

Abstract: The present invention relates to advances in the field of reconfigurable optical networks. In particular, the present invention provides improvements in the technology of light sources for use in optical networks. The optical network according to the present invention includes a single light source that can be used to emit all of the bands and channels needed for transmission. In particular, the single light source in the optical network of the present invention is a mode-locked laser.

Abstract: The invention relates to an access network for exchanging communication signals between a transit network and at least one communication medium of a user. The communication medium is operatively connected to an exchange by means of an optical fiber connection for exchanging the communication signals, and the exchange is connected to the transit network. The fiber connection comprises at least one multimode fiber, which is bent over at least one first part of its length, in such a manner that the fiber comprises at least one complete winding in the first part thereof mainly for maintaining one or more modes of the communication signals into the fiber. Said modes have been selected from a group comprising the ground mode and one or more lower modes near the ground mode.

Abstract: A photodiode and a method of fabricating a photodiode for reducing modal dispersion and increasing travel distance. The central region of the photodiode is made less responsive to incident light than a peripheral region of the photodiode. The less responsive central region discriminates the lower order modes such that only the higher order modes are incident on the more responsive peripheral region. Because the lower order modes are subtracted, the range of propagation constants is reduced and modal dispersion is also reduced.

Abstract: Systems and methods for transmitting quantum and classical signals over an optical network are disclosed, wherein the quantum signal wavelength either falls within the classical signal wavelength band, or is very close to one of the classical signal wavelengths. The system includes a deep-notch optical filter with a blocking bandwidth that includes the quantum signal wavelength but not any of the classical signal wavelengths. The deep-notch optical filtering is applied to the classical signals prior to their being multiplexed with the quantum signals to prevent noise generated by the classical signals from adversely affecting transmission of quantum signals in the transmission optical fiber. Narrow-band filtering is also applied to the quantum signals prior to their detection in order to substantially exclude spurious non-quantum-signal wavelengths that arise from non-linear effects in the optical fiber.

Abstract: A single-to-multi mode converter and an optical code division multiple access system using the same. The mode converter includes first, second, and third optical waveguides. The first optical waveguide is formed of a single-mode optical fiber and outputs a single-mode optical signal. The second optical waveguide converts the single-mode optical signal output from the first optical waveguide to a multi-mode optical signal and allows the optical power of the single-mode optical signal to be coupled to each mode of the multi-mode optical signal. The third optical waveguide is formed of a multi-mode optical fiber and transmits the multi-mode optical signal output from the second optical waveguide.

Abstract: A multimode fiber system includes a transmitter for transmitting an optical signal and a receiver that receives the optical signal. At least one mode filter is coupled between the receiver and the transmitter and passes only a specific set of fiber modes from the transmitter to be received by the receiver. The at least one mode filter comprises a tapered core section that includes a double taper configuration joined at the narrowest regions and in which each end of the two tapers has dimensions compatible with the fiber at that end.

Abstract: A network for distributing signals to a plurality of user apparatuses having a distribution unit with a plurality of ports, and a plurality of optical-fiber cables connected to the ports and suitable to make the plurality of ports of the distribution unit communicate with the plurality of user apparatuses. At least one of the plurality of optical-fiber cables is an electrically terminated optical cable having an optical cable with a single-mode optical fiber and an opto-electronic end portion mechanically and permanently connected to an end of the optical cable, and the opto-electronic end portion has an opto-electronic conversion device having an optic port optically aligned with and mechanically connected to, an end of the single-mode optical fiber.

Abstract: Optical signals are received from a free-space link by directing received light onto a plurality of microlenses and then directing light received through each of the microlenses into a respective single mode optical fiber (SMF). Light beams from the SMFs are combined into a single light beam in one SMF. The single light beam is amplified with a multi-wavelength fiber amplifier and attenuated with a variable optical attenuator. The power gain of the multi-wavelength fiber amplifier and the attenuation of the variable optical attenuator are controlled. The single light beam is directed into a fiber optic communication system that is optically coupled to the variable optical attenuator.

Abstract: A method and apparatus is provided for connecting an optical source to a multimode optical fibre in a multimode optical fibre communications system. A single mode fibre length is provided such that optical radiation admitted from an optical source at one end of the single mode fibre length is provided to a multimode optical fibre at the other end of the single mode fibre length. This method and apparatus is used in a duplex patchcord for connecting an optical transceiver to a pair of installed multimode fibres. The second fibre in the patchcord is a multimode fibre for passing optical signals to the optical receiver of the transceiver.

Abstract: A transmission of optical signals generated by multi-line optical sources is provided via multichannel WDM optical network. Each multi-line optical source generates optical spectral lines within designated spectral range associated with the spectral window allocated for corresponding WDM channel, and comprises a plurality of spectral lines. Spectral lines are substantially narrower than the spectral separation between the lines.

Abstract: A passive remote loop-back method and apparatus for optical circuit verification is described. The apparatus may be remotely controlled through either of a dial-up or a data connection. The apparatus is adapted to: perform loop-back of received optical signals; verify status on loss of carrier; and, verify the status of its dual power supplies. The apparatus is also adapted to report alarm conditions by dialing a predetermined telephone number. The advantage is a versatile apparatus that may be monitored by a remote manager, and which automatically reports alarms using a dependable alternate communications medium.