Techniques for transmitting an optical signal through optical fiber with an improved cost effective stimulated Brillouin scattering (SBS) suppression include externally modulating a light beam emitted from a light source with a high frequency signal. The light beam is also modulated externally with an RF information-carrying signal. The high frequency signals are at least twice a highest frequency of the RF signal. The high frequency signals modulating the light source can be gain and phase adjusted by the first set of gain and phase control circuit to achieve a targeted spectrum shape. The adjusted high frequency signals then are split, providing a portion of the split signals to modulate the light source and another portion of the split signals to the second set of phase and gain control circuit for adjusting a phase/gain. The output of second set of phase and gain control circuits can be applied to the external modulator to eliminate intensity modulation caused by the corresponding high frequency signals that modulate the light source. The spread spectrum for SBS suppression or the optical transmitter's SNR is further improved by cancelling a beat between SBS suppression modulation tones and out of band distortion spectrum of information bearing RF signal.

It is desirable to provide a technology capable of improving reliability in light transmission and convenience at the time of connecting a transmission device to a cable with a simple circuit configuration. A transmitting device is provided which includes a connector receptacle unit connected to an optical-electrical composite cable, in which the connector receptacle unit includes a first electrode group, a second electrode group provided at a position rotated from the first electrode group by 180 degrees about a center of a main body of the connector receptacle unit as a reference, a first connection unit group for transmitting optical signals, and a second connection unit group for transmitting optical signals provided at a position rotated from the first connection unit group for transmitting optical signals by 180 degrees about the center of the main body of the connector receptacle unit as a reference.

Disclosed herein are a method for simultaneously transmitting/receiving upstream and downstream signals using a remote PHY architecture and an apparatus for the same. The method determines whether to divide frequencies depending on whether signal interference occurs among multiple cable modems connected to a cable network, if it is determined to divide the frequencies, categorize the multiple cable modems into multiple groups so that signal interference occurs in each group, but signal interference does not occur between groups, set transmission bands for the multiple groups so that an upstream band and a downstream band of one group alternate with upstream bands and downstream bands of remaining groups by dividing the frequencies in accordance with a number of groups, and cancels, by a remote physical layer (PHY) device located at an optical network terminal of the cable network, self-interference signals for respective groups based on the transmission bands.

Dynamic power in cable access networks may be reduced. First, a peak data rate associated with a network may be determined. Then, a modulation order and an associated Radio Frequency (RF) level that will support the determined peak data rate may be determined. Next, a power value to be transmitted by a node in the network based on the determined modulation order and the associated RF level may be determined. A bias value may then be determined for the node to support the determined power value.

A method of detecting CPD in an HFC network is disclosed, where the network includes a return receiver, a cable plant, and a node. The node includes an optical receiver, optical transmitter, a diplexer having forward and return legs, a forward path defined between optical receiver and forward leg, and a return path defined between the optical transmitter and return leg. The optical receiver provides a forward signal to the cable plant and a portion of the forward signal leaks through the return leg and travels to the return receiver. The cable plant contains a CPD source which generates a CPD signal from the forward signal. The CPD signal travels to the return receiver. The method comprises: (a) operating the return receiver to synchronously capture the CPD signal and leaked portion of forward signal; (b) generating from the captured forward signal a reference signal, which substantially simulates the CPD signal; (c) performing a cross-correlation of the reference and captured CPD signals to produce a correlation peak; and (d) detecting the actual CPD signal from the correlation peak.

The present disclosure provides a dither-free bias control of an optical modulator (OM) for the externally-modulated transmitter with the silicon-based Mach-Zehnder modulator (MZM), while the nonlinear distortions (NLDs) are generated by the plasma dispersion effect of the silicon-based MZM. The present disclosure proposes to intentionally offset the bias point of the MZM from its quadrature points, and therefore the Mach-Zehnder interference (MZI)-induced even-order NLDs can be generated to cancel the plasma dispersion-induced even-order NLDs. In addition, the MZM bias control is also proposed to arbitrarily adjust and lock in the bias point of an OM so a transmitter with the integrated MZM may reach the best even-order NLDs by offsetting from the quadrature points. Moreover, while the proposed scheme could arbitrarily adjust and lock in the bias of MZM, the receiver sensitivity may be optimized by using such a bias control scheme to adjust the extinction ratio of multi-level signals.

Automatic gain control (AGC) may be accomplished in a radio frequency (RF) amplifier in a hybrid fiber-coaxial (HFC) network using a wideband RF tuner to select multiple pilot channels (e.g., frequencies in lower and upper portions of an RF signals spectrum) for use in measuring power and determining a correction to be applied to the RF amplifier. The power of the pilot channel or channels may be measured, for example, using a received signal strength indicator (RSSI) from the wideband RF tuner or using a power detector circuit. Using the wideband RF tuner allows selectable gain and/or tilt control across a wideband spectrum, such as a channel spectrum of a CATV downstream RF signal, to maintain stable RF output levels of the amplifier as RF input levels vary. The RF amplifier may be a line extender amplifier used in a CATV HFC network to amplify a wideband RF spectrum of up to 1.8 GHz.

A cable distribution system that includes a head end connected to a plurality of customer devices through a transmission network that includes a remote fiber node that converts digital data to analog data suitable for the plurality of customer devices. The remote fiber node includes a processor. The remote fiber node receives a software image containing (i) a hardware image, (ii) a primary boot loader, (iii) a kernel, (iv) a software dataplane for a dataplane, and (v) software applications for a control plane. Based upon the file name of the software image selectively using at least some of (i) a hardware image, (ii) a primary boot loader, (iii) a kernel, (iv) a software dataplane for a dataplane, and (v) software applications for a control plane, in resetting the remote physical device.

Directional wireless drop systems are provided. These systems include a tap unit that is connected to a communications line of the broadband network; a cable modem unit connected to the tap unit; a plurality of wireless routers connected to the cable modem unit; and a directional antenna unit that is connected to at least a first of the wireless routers. Each wireless router is associated with a respective one of a plurality of subscriber premises that are served by the directional wireless drop system and is configured to communicate with at least one device that is located at the respective one of plurality of subscriber premises.

A communication device in a communication network includes at least one processor. The processor is configured to identify a first management information base (MIB) of a first occupied channel in the communication network, and a second MIB of a second occupied channel in the communication network adjacent the first occupied channel. The second occupied channel occupies a frequency band overlapping with an interfering signal band. The processor is further configured to calculate at least one proactive network maintenance (PNM) metric for each of the first and second MIB, and determine, from the calculated PNM metric, that an ingress of the interfering signal is detected on the second occupied channel.