Abstract: The disclosure relates to an optical receiver having an apparatus for varying decision threshold level and an optical transmission system having the same. An optical receiver having an apparatus for varying decision threshold level includes a photo diode (PD) for receiving an optical signal and transforming the received optical signal into an electrical signal; a trans-impedance amplifier (TIA) for pre-amplifying the electrical signal transformed by the PD; a limiting amplifier (LA) for deciding the electrical signal amplified by the TIA as either level 0 or level 1 and for amplifying the decision signal; a clock and data recovery (CDR) for generating a clock and data from the amplified decision signal by the LA; and a control circuit for adjusting a decision threshold level depending on the received optical signal power by the PD and for providing the adjusted decision threshold level with the LA.

Abstract: A transceiver unit for use at an end-location in a communications network includes a downstream monitor configured to monitor downstream optical signals that travel from a service provider to the end-location. The downstream optical signals carry downstream data for use by a device in communication with the transceiver unit. At least a portion of the optical path traveled by the downstream optical signals is on a common optical fiber that carries downstream optical signals for other end locations. The transceiver unit also includes an upstream attenuator configured to attenuate upstream optical signals traveling from the end-location to the service provider. At least a portion of the optical path traveled by the upstream optical signals is on the common optical fiber. The transceiver unit also includes electronics configured to operate the upstream optical attenuator in response to output from the downstream monitor.

Abstract: An optical transmission device includes an input interface unit, a cross-connecting unit, and an output interface unit, and a bandwidth switching control unit, and switches bandwidths allocated to paths in a transmission channel that connects to an adjoining optical transmission device synchronously with the adjoining optical transmission device. When the bandwidths are not continuous in the transmission channel, the bandwidth switching control unit controls the input interface unit, the cross-connecting unit and the output interface unit to rearrange the non-continuous bandwidths into continuous ones.

Abstract: A PLC modem performs communication via transmission lines made of a pair of cables as an example of a wired transmission line. Data displaying an operation state of the PLC modem is transmitted to a light emitting part via a modulator, and is converted into a high-speed flash signal for output.

Abstract: Provided herein are embodiments of a device, method of use and system for a low-cost analog multi-wavelength video distribution transamplifier for CATV and FTTH networks having a broadband overlay. The transamplifier embodiments described herein allow the use of multiple wavelengths to segment logical service groups in a CATV distribution system and a FTTH system having a broadband overlay. Improved optical signal power performance can be achieved by using direct modulating transmitters and modulating the optical signal for with an external waveguide, thereby decreasing SBS and reducing non-linearities.

Abstract: Disclosed is an optical transmission system capable of transmitting optical signals of E-band and other bands through one optical fiber. The system includes a first thin film filter for receiving optical signals of E-band and other bands at both sides thereof respectively, and multiplexing the optical signals of both E-band and other bands by selectively transmitting wavelength ranges received at one side, reflecting wavelength ranges received at the other side, and then coupling the optical signals of both E-band and other bands; an optical fiber for transmitting the optical signals multiplexed by the first thin film filter to a receiving portion; and a second thin film filter for selectively separating and demultiplexing the E-band and other bands from the optical signals transmitted through the optical fiber.

Abstract: In an optical communications device that generates picture optical signals and optical signals for data communication by wavelength division multiplexing, it is carried out to alter a signal pattern inserted between packet signals of the optical signals for data communication so that a frequency component of a modulation waveform of the signal pattern disperses. The signal pattern is generated by inputting outputs of a counter for counting up a sign bit into a coder adopting a designated coding method.

Abstract: Avalanche amplification structures including electrodes, an avalanche region, a quantifier, an integrator, a governor, and a substrate arranged to detect a weak signal composed of as few as several electrons are presented. Quantifier regulates the avalanche process. Integrator accumulates a signal charge. Governor drains the integrator and controls the quantifier. Avalanche amplifying structures include: normal quantifier, reverse bias designs; normal quantifier, normal bias designs; lateral quantifier, normal bias designs; changeable quantifier, normal bias, adjusting electrode designs; normal quantifier, normal bias, adjusting electrode designs; and lateral quantifier, normal bias, annular integrator designs. Avalanche amplification structures are likewise arranged to provide arrays of multi-channel devices. The described invention is expected to be used within photodetectors, electron amplifiers, chemical and biological sensors, and chemical and biological chips with lab-on-a-chip applications.

Abstract: A method of compensating phase error between parallel digital signals of a received optical signal, in a coherent optical receiver. A phase differential between the digital signals is determined. A digital skew is imposed between the digital signals, an amount of skew imposed being an integer number of sample periods calculated to most nearly compensate the phase differential. The skewed digital signals are then digitally processed, in the frequency domain, to compensate a residual portion of the phase differential.

Abstract: Embodiments of a system are described. This system includes an array of chip modules (CMs) that are configured to communicate data signals with each other via optical communication. In a given CM module, optical signal paths, such as waveguides, are routed in the same way as in the other CMs in the array. In this way, a common optical design in the CMs may be used in the system to prevent data conflicts during the optical communication.

Abstract: A dispersion compensation method comprising the steps of: a) providing a compensation node for each predetermined number of in-line repeaters; b) carrying out dispersion compensation for the in-line repeaters with the different bit rates in common; c) carrying out wavelength demultiplexing on the optical signal for each of the different bit rates in the compensation node; and d) setting an optimum dispersion compensation amount for the optical signal of each bit rate.

Abstract: An operational optical transceiver configured to initiate operation in loop back mode. The optical transceiver includes transmit and receive signal paths, a memory capable of having microcode written to it, and a configurable switch array that is used to connect and disconnect the two signal paths as appropriate for a desired loop back mode. The microcode is structured to cause the optical transceiver to control the configurable switch array. This allows for analysis and diagnostics of the signal data.

Abstract: An interferometer for demodulating a differential M-phase shift keying signal includes a PLC type interferometer main body, a heating portion that heats the PLC type interferometer main body, and an intermediate member having a higher stiffness than that of the PLC type interferometer main body, for bonding the PLC type interferometer main body and the heating portion with each other while being sandwiched therebetween. A linear expansion coefficient difference between the PLC type interferometer main body and the intermediate member is equal to or smaller than 4.5×10?6/° C., and a thermal conductivity difference between the PLC type interferometer main body and the intermediate member is equal to or larger than 10 W/mK. A phase of an optical signal flowing through the interferometer is adjusted by using the heating portion and a second heating portion.

Abstract: Systems and methods for validating a data link between two communication modules, such as optical transceiver modules configured for bidirectional optical communication, are disclosed. In one embodiment a method according to the invention includes a first optical transceiver module transmitting a first validation optical signal to a second optical transceiver module via an optical waveguide, such as an optical fiber, that physically interconnects both transceivers. The first validation optical signal is received by the second optical transceiver module, which lights an indicator light on its housing and returns a second validation optical signal to the first optical transceiver module. Upon receipt of the signal, the first transceiver lights its indicator light and enables data transfer to occur between both transceivers.

Abstract: A circuit for transmitting signals in a network node, particularly for a channel card for an optical WDM signal transmission device, with a first holding device assigned to the local side of the network node, which can be freely equipped by means of a local-side transceiver unit and which has an internal transmitting port connection and an internal receiving port connection which, in case first holding device is equipped with local-side transceiver unit, are connected to the respective transmitting or receiving ports of local-side transceiver unit, with two additional holding devices assigned to the remote side of the network node having similar ports. A controllable signal switching unit is provided with novel construction to configure connections between the respective internal ports.

Abstract: In an optical communication system, a pre-compensation is conducted for an influence of a polarization dispersion and a polarization dependent loss, which an optical signal transmitted from a transmitter station to a receiver station receives from a communication channel, at a transmitter station. The influence of the polarization dispersion and the polarization dependent loss from the transmission channel is cancelled when the receiver station receives the optical signal.

Abstract: An optic signal transmit system and biasing method and apparatus and system is disclosed to reduce power consumption during non-transmit periods. An optic signal generator receives a bias signal and an outgoing signal. A burst/transmit enable signal enables the transmit system into transmit mode, such as during a transmit window in a time multiplexed environment such as PON networks. A bias circuit biases the driver and/or optic signal generator. To realize power savings, the bias circuit includes one or more stages which are selectively enabled to adequately bias the driver and optic signal generator during transmit windows but disabled during periods when the system is not transmitting. The bias circuit may comprise a current mirror with a reference device, a fixed device, and switched device, which is selectively included in the circuit by a bias switch. The bias switch is responsive to a burst/transmit enable signal or a signal related thereto.

Abstract: A method of operating a WDM transmission system with at least one transmitter and at least one receiver connected by means of a dispersive transmission line.

Abstract: A communication recovering system for a wavelength division multiplexed passive optical network (WDM PON) includes a central office and remote nodes. When there is a fault in an optical fiber connecting a first blue/red band coupler to a blue/red band coupler R11, optical signals are inputted/outputted thereto/therefrom through a first 1×2 optical switch and a second blue/red band coupler, and when there is a fault in an optical fiber connecting the second blue/red band coupler to a blue/red band coupler R21, optical signals are inputted/outputted thereto/therefrom through the second 1×2 optical switch and the first blue/red band coupler.

Abstract: Apparatuses and methods are provided which suppress a surge component occurring at an optical amplifier on an optical path through which an optical burst signal is transmitted. An optical amplifier may experience a surge due to the power variation of the optical burst signal that is fed to the optical amplifier. To suppress such a surge component, a power corresponding to a number of wavelengths of an optical burst signal to be input is calculated. The optical amplifier is instructed to generate an optical signal with a power corresponding to a difference between a set value and the calculated power. The generated optical signal and the optical burst signal to be input are coupled and output according to the instruction. Thus, the optical amplifier can receive the optical signal with the constant power and the surge component at the optical amplifier can be suppressed.