201 results about "Optical add-drop multiplexer" patented technology

A loss-less, optical add/drop multiplexer according to the present invention includes a rare earth-doped fiber amplifier integrated with a wavelength-selective fiber path coupled between two directional optical transfer devices for selectively adding and dropping optical signals from a multi-wavelength signal, such as a wavelength division multiplexed optical signal. One or more fiber gratings are disposed along the length of the rare earth-doped fiber amplifier or between segments of the rare earth-doped fiber so that at least one grating is used for reflecting each optical signal that is expected to be added to or dropped from the multi-wavelength optical signal. By using this configuration, appropriate amplification is provided to compensate for losses in the add, drop, and through paths.

The present invention relates to an optical cross connect unit comprising M wavelength separating sections for receiving multiplexed optical signals each having N kinds of wavelengths different from each other through M optical fibers, respectively, and for wavelength-separating each of the multiplexed optical signals into N optical signals, M optical reproduction relay sections each for conducting an optical reproduction and relay in a manner of making a conversion of each of the N optical signals, wavelength-separated in each of the wavelength separating sections, into an electric signal and then modulating it with a desired optical wavelength, a refill section for mutually refilling M sets of optical signals optically reproduced and relayed in the optical reproduction relay sections, a focusing section for focusing the M sets of optical signals refilled in the refill section, and a light source unit for supplying input lights having desired wavelengths to be modulated in the M optical reproduction relay sections. The light source unit includes N light sources for outputting lights having the N kinds of optical wavelengths, a multiplexing and branching section for multiplexing the lights from the N light sources to produce a multiplexed light having N kinds of optical wavelength components and further for branching the multiplexed light into MxN lights to output them as multiplexed and distributed lights, M wavelength filter sections for distributively receiving N multiplexed and distributed lights of the MxN multiplexed and distributed lights branched in the multiplexing and branching section to output N lights due to the passage of only arbitrary wavelengths of the N kinds of optical wavelengths, and a wavelength setting control section for setting optical wavelengths, which pass through the wavelength filter sections, so that they differ from each other. The N lights from each of the M wavelength filter sections are supplied as the input lights. In the case that many light sources are necessary for the modulation processing by modulators or the like, this optical cross connect unit is also suitable because of using given wavelengths from a small number of light sources for a lot of modulation processing.

The present disclosure provides optimized configurations for a directionless reconfigurable optical add/drop multiplexer application. The present invention includes an add module with improved optical signal-to-noise through placing amplifiers prior to a multi-cast optical switch. The present invention includes various drop module configurations utilizing distributed gain, channel selective filters, and bi-directional configurations to reduce power consumption and complexity. Additionally, the present invention includes an integrated broadcast and select architecture.

The present invention provides a signal distribution module for use in a directionless reconfigurable optical add/drop multiplexer application, including: a multi-cast switch having a plurality of input ports and a plurality of output ports; a plurality of optical amplifiers coupled to the plurality of input ports of the multi-cast switch, wherein the plurality of optical amplifiers form an optical amplifier array; a tunable optical splitter coupled to the plurality of optical amplifiers; and a pump laser coupled to the tunable optical splitter.

A reconfigurable optical add drop multiplexer core device includes a light distributor, a light combiner, and first and second sets of add and drop ports. The light distributor is configured to receive an optical signal along a primary input of the reconfigurable optical add drop multiplexer core device and to distribute the received optical signal along a plurality of subtending outputs. The light combiner is configured to receive optical signals along a plurality of subtending inputs, to combine the received optical signals into a combined signal, and to output the combined signal. The add and drop ports in the first set function as add and drop ports, respectively, and the add and drop ports in the second set function as both add and drop ports, respectively, and as express ports connectable to another reconfigurable optical add drop multiplexer core device.

In an Optical Add-Drop Multiplexer, a drop section comprises a Wavelength Selective Switch (WSS) having at least one drop-port, the WSS being operative to couple a respective set of w (where w>1) wavelength channels from a received Wavelength Division Multiplexed (WDM) signal to each drop port. A respective 1:s power splitter is associated with each drop port. Each power splitter supplies the respective set of channels received from its drop port to each one of a corresponding set of coherent receivers. Each coherent receiver operates to receive a selected one of the respective set of channels.

A system and method for limiting the impact of an unstable wavelength on other wavelengths in a reconfigurable optical add/drop multiplexer (ROADM) network are disclosed. The method generally comprises measuring optical channel power at prescribed time intervals; for each measurement of channel power falling outside a predefined threshold, recording a threshold crossing event; comparing the recorded threshold crossing events to stored criteria indicative of an unstable wavelength channel; and removing an unstable wavelength from the ROADM network if the threshold crossing events exceed the stored criteria.

Effects of diffraction of a spectral beam from an edge of the micromirrors are reduced in order to optimize the passband in a wavelength selective switch. The effects of diffraction on the pass band may be reduced by appropriate modification of the edges of the micromirrors, by modification of the input and/or output ports to allow for attenuation by rotation of the micromirror about the switching axis, by using rotation of the micromirror about both the attenuation axis and the switching axis to achieve the desired level of attenuation, by inserting an aperture at a focal plane or external to the device to reduce the magnitude of the micromirror edge diffraction transmitted to any or all output ports, or by appropriate filtering of angular frequencies with a diffraction grating used to separate a multi-channel optical signal into constituent spectral beams.

An embodiment of the invention provides a restructurable ROADM (optical add-drop multiplexer) and WXC (wavelength cross connect), and relatest to the field of communications, the ROADM comprises a line side wavelength switching module, an upper wave module, and a lower wave module; the upper wave module comprises a tunable multiplexer, a first optical switch and a transmitter; the first optical switch is used for connecting the fiber optical wavelength transmitted by the transmitter to the tunable multiplexer; the tunable multiplexer is used for multiplexing the received fiber optical wavelength, generating a WDM optical signal for wavelength division multiplexing, and outputting the WDM optical signal to the line side wavelength switching module; the lower wave module comprises a tunable demultiplexer, a second optical switch and a receiver, the tunable demultiplexer is used for demultiplexing the WDM optical signal from the line side wavelength switching module and outputting the signal through demultiplexing to the second optical switch, and the second optical switch is used for connecting the fiber optical wavelength through demultiplexing to the receiver. The embodiment of the invention reduces cost of ROADM.

The present invention discloses a concept of natural index contrast (NIC) for producing photonic waveguides and methods of fabrication thereof. Such waveguide forms the basis of a class of chip-scale micro- and nano-photonic integrated circuits (PICs). The NIC method utilizes the built-in refractive index difference between two layers of dielectric thin films of two different materials, one laid on top of another. This new class of waveguides simplifies the PIC fabrication process significantly. Based on the NIC based waveguides, PICs can be fabricated for a number of photonic applications such as arrayed waveguide grating (AWG), reflective arrayed waveguide grating (RAWG), interleaver, interferometer, and optical sensor. Additionally, several other PICs can also be fabricated via tiers of integration, such as triple-phase integration. Examples of such devices include optical amplifier, wavelength router, sensor, optical modulator, transmitter, receiver, transponder, fully built dense wavelength division multiplexer and demultiplxer, optical power splitter, multicahnnel tunable optical attenuator, and multicahnnel tunable optical add-drop multiplexer. Unlike hybrid integration, triple-phase integration monolithically integrates multiple optical functionalities on a single chip.

Individual channels of a multiplexed laser array in a multi-channel optical transmitter are monitored at an output of an optical multiplexer. The monitoring may be used to confirm proper operation of each of the channels in the multiplexed laser array and/or to perform wavelength locking on each of the channels. Monitoring at the output of the optical multiplexer avoids the use of multiple photodetectors coupled directly to multiple lasers in the multiplexed laser array. The multiplexed laser array generally includes a plurality of laser emitters optically coupled to an optical multiplexer such as an arrayed waveguide grating (AWG). An optical transmitter with a monitored multiplexed laser array may be used, for example, in an optical line terminal (OLT) in a wavelength division multiplexed (WDM) passive optical network (PON) or in any other type of WDM optical communication system capable of transmitting optical signals on multiple channel wavelengths.

The present invention provides a reconfigurable optical add/drop multiplexing device for enabling a totally inresistant colorless, wherein a dropping unit is configured to separate multi-wavelength optical signals which are among direction 1˜X and are broadcast inputted in a circuit direction, switch the multi-wavelength optical signals among the direction 1˜X to any corresponding output port through multiple N×N optical switches, and send the optical signals to a corresponding Receiver (RX) after combining the received optical signals by a corresponding K×1 coupler/optical switch; an adding unit is configured to broadcast the optical signals sent by a Transmitter (TX) to the multiple N×N optical switches through N 1×K couplers/optical switches, switch the optical signals to any corresponding output port by each optical switch, and output the corresponding optical signals in the direction 1˜X to the circuit direction after the optical signals are implemented with optical multiplexing; wherein, X is an integer which is greater than or equal to 2, and K and N are both integers. The present invention can enable the totally inresistant colorless in adding and dropping units.

An optical signal quality degradation monitoring apparatus for monitoring an optical wavelength division multiplex signal is implemented in a small size. To monitor the optical signal quality degradation in the optical wavelength division multiplex signal by a configuration as simple as possible, the following configurations are used: A configuration using an optical wavelength division demultiplexer and a sampling clock generator to make one an electric signal processor; A configuration using an optical sampling pulse train generator, an optical multiplexer, a nonlinear optical medium, and an optical wavelength division demultiplexer to make one an electric signal processor; or a configuration using a selection wavelength control section, an optical wavelength selecting section, and a sampling clock generator to make one electric signal.

There is provides a wavelength conversion apparatus for converting a wavelength of input signal light and for outputting output signal light of the converted wavelength. The apparatus includes a first and a second nonlinear mediums. The first nonlinear medium receives a first input light and outputs a first output light having a wavelength which is longer than that of the first input light, the wavelength being dependent on optical power of the first input light. The second nonlinear medium receives a second input light and a light output by a light source and outputs a second output light having a wavelength dependent on the wavelengths of the second input light and the light. The first output light is input as the second input light to the second nonlinear medium or the second output light is input as the first input light to the first nonlinear medium.

The present invention provides a wavelength-switched reconfigurable optical add-drop multiplexer (R-OADM) with wavelength broadcasting capability, such that asymmetric video signal distribution and the like can be performed without sacrificing with respect to component complexity and expense. The present invention utilizes an optical splitting and combining device with the wavelength-switched R-OADM to allow the R-OADM to support network-wide wavelength broadcasts without requiring external regeneration and extra optical transceiver equipment.

An apparatus includes a wavelength-selective switch having an optical demultiplexer having N optical outputs, a first optical multiplexer having N optical inputs, a second optical multiplexer having N optical inputs, and a plurality of controllable 1×P optical switches. Integer P is greater than or equal to 2. Each of the optical switches is connected to a corresponding one of the optical outputs of the optical demultiplexer and is connected to corresponding ones of the optical inputs of the respective first and second optical multiplexers. The optical AWG demultiplexer has an optical AWG sampling coefficient of one or more for light with a wavelength in the optical telecommunication C-band, L-band, or S-band.

A resonator structure is presented comprising a closed loop resonator waveguide having a width varying over the circumferential region of the resonator waveguide. The resonator structure can be used in various applications, such as optical filters, lasers, modulators, spectrum analyzers, wavelockers, interleave filters, and optical add drop multiplexers.

The invention relates to an all optical network interconnection system of a passive optical network and a metropolitan area network which belong to the technical field of optical fiber communications, and the system includes a center bureau, a downlink transmission link, an uplink transmission link, 1*N optical coupler and N corresponding optical network units, wherein, the center bureau consists of an optical add-drop multiplexer and an optical line terminal, and the center bureau is connected with the metropolitan area network via the optical add-drop multiplexer and is accessed into the passive optical network; the optical line terminal is connected with the 1*N optical coupler via an optical fiber, and the output end of the 1*N optical coupler is connected with the N optical network units to form the downlink transmission link; the N optical network units are connected with another optical fiber of the same length via another likewise 1*N optical coupler to form the uplink transmission link, and the uplink data is transmitted to the optical line terminal. The invention does not need electro-optic or optical-electrical conversion, and the optical network units do not need the light source, thereby greatly saving the cost of the passive optical network, and the utility model can be connected with more optical network units.