Abstract: A transmission network includes network elements which accept client signals to be transported over a transmission network, particularly an optical transmission network, each of the client signals having one of a plurality of payload rates. The client signals are digitally mapped into first transport frames and, subsequently, digitally mapped into second transport frames for transport across the network infrastructure. The second transport frames having a universal frame rate throughout the transmission network infrastructure supporting a client signal of any frequency, whether the client signal includes a standard client payload or a proprietary client payload.

Abstract: A method and apparatus is provided for tracking a thermally floating wavelength signal channel grid generated at an optical transmitter (Tx) in an optical transmission system or optical network where the wavelengths of the individual Tx signal channels may move in wavelength due to, for example, changes in ambient temperature at the optical transmitter but the channel spacing between Tx signal channels along the thermally floating Tx wavelength grid remains constant.

Abstract: A geometrically shaped optical waveguide crossing with minimal transmission loss is described. A symmetrically tapered waveguide intersection is used to minimize loss in the intersecting region where at least two optical waveguides cross one another. The present invention embodies a waveguide crossing that includes tapering the width of the waveguides as they approach the intersecting region, forcing the field of light to contract, reducing asymmetric field distortions, and thus reducing transmission loss and effectively minimizing crosstalk. This is accomplished by focusing light through a perpendicular or near perpendicular intersection by simple linear tapering rather than by the use of a lens or other previously used devices.

Abstract: A photonic integrated circuit (PIC) chip comprising an array of modulated sources, each providing a modulated signal output at a channel wavelength different from the channel wavelength of other modulated sources and a wavelength selective combiner having an input optically coupled to received all the signal outputs from the modulated sources and provide a combined output signal on an output waveguide from the chip. The modulated sources, combiner and output waveguide are all integrated on the same chip.

Abstract: Optical autodiscovery is provide between two optical modules to insure that when an optical signal is coupled between the two optical module, the optical signal from a first module does not interfere with operation of a second module. The autodiscovery is implemented by sending an optical identification signal from the first optical module via the coupling to the second optical module from which signal, the second optical module can verify and determined acceptance of the coupled first optical module. During this autodiscovery process, the optical identification signal from the first optical module may be attenuated or shifted in optical spectrum so as not to interfere with the operation of the second optical module. Autodiscovery may also be employed in cases where a first optical module is to receive an optical signal from a second module.

Abstract: A photonic integrated circuit (PIC) for a PON transceiver comprises a single monolithic chip having a modulated transmitter laser diode of a first wavelength, ?1, for generating a first communication signal outgoing from the chip via an input/output port and a receiving photodetector for receiving a second communication signal of a second wavelength, ?2, onto chip incoming from the input/output port and a monitoring photodetector for receiving a portion of the first communication signal to monitor the laser diode output power.

Abstract: The present invention provides a system, apparatus and method for recovering a client signal clock. The present invention is able to more effectively remove jitter within a clock signal by providing a phase shifting element in the feedback of a PLL system to compensate for sudden changes in an input reference clock. The PLL system provides flexible clock recovery so that it can accommodate various payload types because it extracts a client clock signal independent of a corresponding justification count number.

Abstract: A monolithic receiver photonic integrated circuit (RxPIC) chip includes a plurality of optical signal channels together with other active elements integrated on a semiconductor chip, which chips further include a wavelength selective decombiner comprising a supergrating or an Echelle grating which provides for a more compact chip compared to an integrated on-chip arrayed waveguide grating (AWG) functioning as a wavelength selective decombiner.

Abstract: Method and apparatus for utilizing a probe card for testing in-wafer photonic integrated circuits (PICs) comprising a plurality of in-wafer photonic integrated circuit (PIC) die formed in the surface of a semiconductor wafer where each PIC comprises one or more electro-optic components with formed wafer-surface electrical contacts. The probe card has a probe card body with at least one row of downwardly dependent, electrically conductive contact probes. The probe body is transversely translated over the surface of the wafer to a selected in-wafer photonic integrated circuit (PIC) die. Then, the contact probes of the probe card are brought into engagement with surface electrical contacts of the selected photonic integrated circuit (PIC) die for testing the operation of electro-optic components in the selected in-wafer photonic integrated circuit (PIC) die.

Abstract: A system, apparatus, and method for providing a plurality of internal VLANs within a networking element/node are described. Internal VLAN topologies are provisioned so that a particular VLAN(S) communicate traffic to corresponding applications. This segregation of internal traffic across a VLAN topology reduces the amount of interference between the traffic. Redundancy across the VLAN topology is provided so that traffic may be switched to another path in the event of a failure.

Abstract: A photonic integrated circuit (PIC) chip comprising an array of modulated sources, each providing a modulated signal output at a channel wavelength different from the channel wavelength of other modulated sources and a wavelength selective combiner having an input optically coupled to received all the signal outputs from the modulated sources and provide a combined output signal on an output waveguide from the chip. The modulated sources, combiner and output waveguide are all integrated on the same chip.

Abstract: An optical transmission network is inherently asynchronous due to the utilization of a variable overhead ratio (V-OHR). The network architecture makes extensive use of OEO regeneration, i.e., deals with any electronic reconditioning to correct for transmission impairments, such as, for example, FEC encoding, decoding and re-encoding, signal reshaping, retiming as well as signal regeneration. The optical transmission network includes a plesiochronous clocking system with intermediate nodes designed to operate asynchronously with a single local frequency clock without complicated network synchronization schemes employing high cost clocking devices such as phase locked loop (PLL) control with crystal oscillators and other expensive system components.

Abstract: A photonic integrated circuit (PIC) chip comprising an array of modulated sources, each providing a modulated signal output at a channel wavelength different from the channel wavelength of other modulated sources and a wavelength selective combiner having an input optically coupled to received all the signal outputs from the modulated sources and provide a combined output signal on an output waveguide from the chip. The modulated sources, combiner and output waveguide are all integrated on the same chip.

Abstract: A monolithic optical transmitter photonic integrated circuit (TxPIC) comprises a plurality of integrated modulated sources which, when all operated at constant current, display a power output that varies as a function of array position similar to a quadratic-shaped curve and, further, forming an array of signal channels each having a different wavelength output. An optical combiner/decombiner is integrated in the circuit and has at least one free space region with a plurality of ordered bands along its edge where the zero order band is substantially at a longitudinal centerline of the free space region and where, on either side of this band, is a first order band followed by additional higher order bands.

Abstract: A forward error correction (FEC) communication device that includes a transmitter photonic integrated circuit (TxPIC) or a receiver photonic integrated circuit (RxPIC) and a FEC device for FEC coding at least one channel with a first error rate and at least one additional channel with a second error rate, wherein the first error rate is greater than the second error rate. The TxPIC chip is a monolithic multi-channel chip having an array of modulated sources integrated on the chip, each operating at a different wavelength, wherein at least one of the modulated sources is modulated with a respective FEC encoded signal. The TxPIC also includes an integrated wavelength selective combiner for combining the channels for transport over an optical link.

Abstract: A power monitoring and correction to a desired power level of a laser or group of lasers utilizes two photodetectors which are employed to accurately determine the amount of output power from the front end or “customer” end of a laser or a plurality of such lasers. During power detection, which may be accomplished intermittently or continuously, the laser is modulated with a tone of low frequency modulation. One photodetector at the rear of the laser is employed to detect the DC value of the frequency tone, i.e., a value or number representative of the AC peak-to-peak swing, amplitude or modulation depth of the tone. Also, the rear photodetector may be employed to determine the optical modulation index (OMI). In either case, these values may be employed in a closed loop feedback system to adjust or otherwise calibrate the value of the low tone frequency relative to the total desired bias current applied to the laser.

Abstract: An optical transmission network is inherently asynchronous due to the utilization of a variable overhead ratio (V-OHR). The network architecture makes extensive use of OEO regeneration, i.e., deals with any electronic reconditioning to correct for transmission impairments, such as, for example, FEC encoding, decoding and re-encoding, signal reshaping, retiming as well as signal regeneration. The optical transmission network includes a plesiochronous clocking system with intermediate nodes designed to operate asynchronously with a single local frequency clock without complicated network synchronization schemes employing high cost clocking devices such as phase locked loop (PLL) control with crystal oscillators and other expensive system components.

Abstract: A photonic integrated circuit (PIC) chip comprising an array of modulated sources, each providing a modulated signal output at a channel wavelength different from the channel wavelength of other modulated sources and a wavelength selective combiner having an input optically coupled to received all the signal outputs from the modulated sources and provide a combined output signal on an output waveguide from the chip. The modulated sources, combiner and output waveguide are all integrated on the same chip.

Abstract: A transmissive active channel element is provided in each signal channel of a monolithic multi-channel TxPIC where each channel also includes a modulated source. The active channel element functions both as a power control element for both monitoring and regulating the output channel signal level of each signal channel and as a modulator for channel wavelength tagging or labeling to provide for wavelength locking the modulated sources. The power regulating function is also employed to control the channel signal power outputs of each channel to be uniform across the channel signal array. All of these functions are carried out by a feedback loop utilizing digital signal processing.

Abstract: A photonic integrated circuit (PIC) chip comprising an array of modulated sources, each providing a modulated signal output at a channel wavelength different from the channel wavelength of other modulated sources and a wavelength selective combiner having an input optically coupled to received all the signal outputs from the modulated sources and provide a combined output signal on an output waveguide from the chip. The modulated sources, combiner and output waveguide are all integrated on the same chip.