Polarization beam splitter
Granted: September 4, 2012
Patent Number:
8260136
Consistent with the present disclosure, a polarization multiplexed optical signal having optical signals with both TE and TM polarizations is supplied to an input of a polarization beam splitter (PBS). The PBS includes a first output that supplies TE polarized optical signals and a second output supplies TM polarized optical signals. A first polarizer is coupled to the second output of the PBS to pass the TM polarized optical signals, while rejecting light having other polarizations,…
Modulator driver circuit having chirped components
Granted: August 28, 2012
Patent Number:
8253508
Embodiments of the present invention provide arrays of electrical circuits having one or more chirped elements or components for providing output signals to corresponding arrays of electro-optic devices. Certain embodiments of the present invention include a plurality of modulator driver circuits, each of the plurality of driver circuits configured to be substantially identical to each other and provide a corresponding one of a plurality of modulator drive signals to a respective one of…
Skew compensation across polarized optical channels
Granted: August 21, 2012
Patent Number:
8249463
Embodiments of the present invention provide systems, devices and methods for managing skew within a polarized multi-channel optical transport system. In a DP-QPSK system, skew between polarized channels is compensated within the transport system by adding latency to at least one of the polarized channels. The amount of added latency may depend on various factors including the skew tolerance of the transport system and the amount of skew across the channels without compensation. This…
Polarization beam splitter-polarization rotator structure
Granted: August 7, 2012
Patent Number:
8238697
A polarization beam splitter-polarization rotator-polarization beam combiner optical structure comprising a pair of polarization rotators having a polarization beam splitter associated with the input ends of the two polarization rotators, and a polarization beam combiner associated with output ends of the two polarization rotators, and a method of purifying a light signal comprising TE and TM modes by disassociating the primary TE and TM modes from first order splitter and rotation error…
Method for wavelength assignment in a WDM network
Granted: August 7, 2012
Patent Number:
8238748
In accordance with the present disclosure, a method of configuring a wavelength division multiplexed (WDM) network is presented. The WDM network includes circuits that carry optical signals, with each signal corresponding to a wavelength. The WDM network includes nodes, with links connecting the nodes to one another. Each circuit includes at least one link and at least one node. The method comprises assigning each of the circuits to an optical signal, based on first and second criteria,…
Three-arm DQPSK modulator
Granted: August 7, 2012
Patent Number:
8238758
A modulator is disclosed that includes three arms between a splitter portion and a coupler portion. The modulator typically requires at most a ?/2 phase shift between constellation points. Accordingly, the modulator is more efficient and consumes less power.
High capacity transmitter implemented on a photonic integrated circuit
Granted: August 7, 2012
Patent Number:
8238759
A high capacity optical transmitter implemented on a photonic integrated circuit chip comprises a single light source which supplies a continuous wave having a particular wavelength to a plurality of modulators to form modulated optical information signals. A phase shifter is coupled to at least one of the modulators and is used to shift the phase of the corresponding modulated optical information signal associated with a particular modulator. A polarization beam combiner receives each…
Optical receiver with improved noise tolerance
Granted: August 7, 2012
Patent Number:
8238760
The present invention provides a system, apparatus and method to improve the signal-to-noise ratio performance in receivers configured to receive differential data signals. According to various embodiments of the invention, a received differential signal is processed to consider both forward-looking and backward-looking error components to improve SNR performance, and ultimately the reach of the optical line system. Additional processing is provided to further enhance noise tolerance…
Dual output laser source
Granted: July 31, 2012
Patent Number:
8233510
A dual output laser source provided on a substrate outputs light from a first and second output. A portion of the light generated by the laser is supplied to a first modulator via the first output. A second portion of the light generated by the laser is supplied to a second modulator via the second output. The first modulator is provided on the substrate and generates a first modulated signal. The second modulator is also provided on the substrate and generates a second modulated signal.…
Software distribution and cache management across client machines on a network
Granted: July 24, 2012
Patent Number:
8230414
A system, apparatus and a method are described for providing efficient software distribution and cache management on a plurality of client machines in a network. In one embodiment of the invention, a cache management software agent is installed on one or more client machines to monitor a status of software versions stored locally on the machines. The cache management software agent performs a check before uploading a matching version of a large software application from a network element…
Programmable time division multiplexed switching
Granted: July 17, 2012
Patent Number:
8223803
A network device may include a set of switches. Each of the switches may include a set of ingress links and a set of egress links. One of the switches may store mapping information that identifies a first timeslot and one of the egress links for data received, during a second timeslot, on one of the ingress links. The one of the switches may receive data, associated with the second timeslot, on the one of the ingress links, identify the first timeslot and the one of the egress links,…
Tunable optical filter
Granted: July 17, 2012
Patent Number:
8224139
Consistent with the present disclosure a compact, integrated tunable filter is provided that can adjust the power levels of optical signals output from an optical amplifier, for example, so that the amplifier has a uniform spectral gain. The tunable optical filter includes a planar lightwave circuit (PLC) having cascaded Mach-Zehnder interferometers, each of which having corresponding differential optical delays. At least one of the differential optical delays is different than the rest.…
Optical receiver including a filter on a planar lightwave circuit
Granted: July 3, 2012
Patent Number:
8213799
A planar lightwave circuit (PLC) includes a substrate, a tunable filter, a demultiplexer (DEMUX), and an optical processor each disposed on the substrate. The tunable filter is configured to filter at least one of a bandwidth or a wavelength of a Wavelength Division Multiplexed (WDM) optical input signal. The DEMUX is connected to the tunable filter and configured to receive a filtered WDM optical input signal at an input and to supply one of a plurality of channels of the filtered WDM…
Receiver on a photonic IC
Granted: July 3, 2012
Patent Number:
8213802
An optical receiver includes a first substrate including a demultiplexer and a first optical waveguide array. An input of the demultiplexer is configured to receive a wavelength division multiplexed optical input signal having a plurality of channels. Each of the plurality of channels corresponds to one of a plurality of wavelengths. Each of the plurality of outputs is configured to supply a corresponding one of the plurality of channels. The first optical waveguide array has a plurality…
Transimpedance amplifier having a shared input
Granted: June 19, 2012
Patent Number:
8204388
Consistent the present disclosure, a receive circuit is provided that includes a balanced detector portion and a transimpedance amplifier (TIA). The anode of one photodiode is connected to the cathode of the other by a bonding pad, which supplies the sum of the currents generated in each photodiode to an input of the TIA. Thus, the TIA may, for example, have a single input, as opposed to multiple inputs, thereby reducing the number of connections so that the photodiodes and the TIA may…
Devices for conversion between serial and parallel data
Granted: May 29, 2012
Patent Number:
8188894
Serial-to-parallel and parallel-to-serial conversion devices may provide for efficient conversion of serial bit streams into parallel data units (and vice versa). In one implementation, a device may include delay circuits, each of which being configured to receive a serial data stream. A rotator circuit may receive the delayed serial data streams and rearrange bits in the serial data streams. Register circuits may receive the output of the rotator circuit and collectively output, in…
Digital framer architecture with a framing marker
Granted: May 29, 2012
Patent Number:
8189623
Embodiments of the present invention provide for diverse routing of a plurality of data streams, representative of a client signal of an unknown format, across multiple communication paths of a digital optical network through the use of a marker embedded in the client signal which is then inserted into the client payload portion of a transport frame. The multiple communication paths include different signal and path attributes related to the optical signals which transport the data…
Optical mode coupler
Granted: May 29, 2012
Patent Number:
8189972
An optical coupler includes a first waveguide configured to supply a first optical signal having a wavelength and a second waveguide. The first optical signal having a first mode. The first waveguide has a tapered portion being spaced from the second waveguide by a distance sufficient to facilitate evanescent coupling of the first optical signal from the first waveguide to the second waveguide. A first effective refractive index of the first waveguide at a location in the tapered portion…
Method of tuning optical components integrated in a monolithic photonic integrated circuit (PIC)
Granted: May 22, 2012
Patent Number:
8184929
An optical transmitter comprises a monolithic transmitter photonic integrated circuit (TxPIC) chip that includes an array of modulated sources formed on the PIC chip and having different operating wavelengths approximating a standardized wavelength grid and providing signal outputs of different wavelengths. A wavelength selective combiner is formed on the PIC chip having a wavelength grid passband response approximating the wavelength grid of the standardized wavelength grid. The signal…
Communication network with node bypassed co-routed multi-channel traffic
Granted: May 8, 2012
Patent Number:
8175113
Embodiments of the present invention route a wavelength division multiplexed signal across multiple communication paths using skew characteristics of at least some of the communication paths. The network is a wavelength division multiplexed optical transport network. The plurality of communication paths involves different signal and path attributes such as a plurality of carrier wavelengths, optical carrier groups, physical communication paths (different nodes, different fibers along a…
