Abstract: Digital compensation of chromatic dispersion (CD) effect experienced by optical orthogonal frequency-division multiplexed (OFDM) signal in fiber transmission is provided in the frequency domain using a Fast Fourier Transform/Inverse Fast Fourier Transform (FFT/IFFT) pair with equal length of digital samples prior to OFDM receiver signal processing, wherein the equal length is larger than the length of a FFT used for OFDM subcarrier demultiplexing of the received signal. The OFDM signal processing is independent of fiber CD, so small guard-interval (GI) can still be used to achieve high spectral efficiency even under the experience of large CD. The GI need only to be large enough to accommodate other effects such as polarization-mode dispersion.

Abstract: A medium access control method for optical-fiber TDMA networks is revealed. The TDMA indicates the technique of time-division multiple access which is used to provide medium-sharing environment. Once the MAC protocol implementing traffic control is applied to control access among nodes with the same optical fiber, the medium access in optical networks can be distributed logically and effectively among the nodes so as to improve unfair access in the optical TDMA networks. Therefore, the optical TDMA network is suitable to construct metropolitan area networks (MANs), local area networks (LANs) or subnetworks of public networks for reducing construction cost of networks, increasing bandwidth utilization and improving communicative performance.

Abstract: Provided are an optical transmitter device and an optical transmitter module which are capable of reducing the optical transmitter module size while maintaining a state where an excellent optical transmission waveform quality is obtained over a wide range of frequencies. The optical transmission module (2) includes a semiconductor laser diode device (10), an optical modulator device (12), and a first termination resistor circuit (14-1). A printed circuit board (4) includes a driver IC (16) and a second termination resistor circuit (14-2). A lower cutoff frequency of the first termination resistor circuit (14-1) and an upper cutoff frequency of the second termination resistor circuit (14-2) correspond to each other. An impedance of the first termination resistor circuit (14-1) in a pass frequency band thereof and an impedance of the second termination resistor circuit (14-2) in a pass frequency band thereof correspond to each other.

Abstract: The present invention encompasses a method for 1+1 protection of an optical transmission path comprising a working path and a protection path that connect a first and second terminal node. In a working mode, an optical transmission signal is transmitted via the working path from the first to the second terminal node. At the second terminal node, the optical transmission signal is split into two optical sub-signals, and one of the optical sub-signals is sent via the protection path to a protection-path connection node as a working-path control signal. In the case of an interruption of the signal transmission via the working path, the protection-path connection node detects the absence of the working-path control signal and switches the system from the working mode to a protection mode in which signal transmission is conducted via a separate protection path.

Abstract: In one embodiment, a gain medium for an external cavity diode laser (ECDL) includes a gain section to provide a gain operation on optical energy in the ECDL that is controlled by a first electrical signal, a semiconductor optical amplifier (SOA) section disposed adjacent to the gain section to amplify the gained optical energy responsive to a second electrical signal, and a trench disposed between the gain section and the SOA section to act as an integrated mirror. Other embodiments are described and claimed.

Abstract: A first node receives a first phase modulated optical signal at a first wavelength from a master node. The first node also transmits a first amplitude modulated optical signal to the master node at the first wavelength using a portion of the first phase modulated optical signal as a light source.

Abstract: An optical device that includes multiple optical modulators having actual operating wavelengths at a given temperature is described. Because of differences between the actual operating wavelengths and target operating wavelengths of the optical modulators, heating elements may be used to thermally tune the optical modulators so that the actual operating wavelengths match corresponding carrier wavelengths in a set of optical signals. Furthermore, control logic in the optical device may assign the optical modulators to the corresponding carrier wavelengths based at least on differences between the carrier wavelengths and the actual operating wavelengths, thereby reducing an average thermal tuning energy associated with the heating elements.

Abstract: System, apparatus and method of optical communication are provided for performing digital compensation of the self-phase modulation (SPM) effect experienced by a polarization-division multiplexed (PDM) orthogonal frequency-division multiplexed (OFDM) signal in fiber transmission by compensating a complex digital waveform representing one orthogonal polarization component of the optical PDM-OFDM signal based on both digital waveforms representing two orthogonal polarization components of the PDM-OFDM signal. The compensation of the digital waveform may be further based on an anticipated mean total nonlinear phase shift experienced by the signal during fiber transmission due to SPM. The compensation may be divided into pre-compensation at the PDM-OFDM transmitter and post-compensation at the PDM-OFDM receiver.

Abstract: A mechanism that enables an optical transceiver to grant access to its memory on a per-segment basis. The optical transceiver includes a processor, system memory and a memory access table. The memory access table is comprised of access entries, each of which defines the access condition for a corresponding segment of memory. The processor reads the access entries for a particular segment of the memory. The processor or other optical transceiver component then determines whether or not to grant access to the memory segment based on the access entry read by the processor. Different levels of access control may be accommodated.

Abstract: A visible light communication system and method for transmitting and receiving an information symbol in a visible light communication system for a Color Code Modulation (CCM) scheme using a chromaticity diagram. The method includes determining a first coordinates value corresponding to an information symbol to be transmitted on the chromaticity diagram; determining a first color ratio corresponding to the first coordinates value; determining a second coordinates value corresponding to a compensation symbol for compensating for the first color ratio into a color white and determining a second color ratio corresponding to the second coordinates value; and emitting a visible ray corresponding to each of the first color ratio and second color ratio. The first and second coordinates values are located on a line on the chromaticity diagram.

Abstract: Provided is an optical transmission module that includes: a semiconductor light emitting element for emitting laser light; a first driving unit for providing a first driving current to the semiconductor light emitting element; a switching unit connected between the semiconductor light emitting element and the first driving unit; and a package for accommodating the semiconductor light emitting element, the first driving unit, and the switching unit. The switching unit includes a first input for receiving a first driving current outputted from at least from the first driving unit, a second input for receiving a second driving current for testing the semiconductor light emitting element, and an output connected to the semiconductor light emitting element. The switching unit connects the first input or the second input to the output.

Abstract: An O/E conversion element converts an input NRZ optical signal into an electric signal. A clock recovery circuit recovers a clock signal from the electric signal obtained by the O/E conversion element. A phase modulator applies phase modulation to the NRZ optical signal, using the recovered clock signal. An intensity modulator applies intensity modulation to the NRZ optical signal, using the recovered clock signal. A dispersion medium compensates for a frequency chirp of an optical signal output from the intensity modulator.

Abstract: An optical transmission apparatus includes a network, a plurality of transponders, a monitor, a multiplexer, and demultiplexer. The plurality of transponders connected with the network, each of the plurality of transponders having a response transfer processing unit for communicating between the other transponders via the network, the plurality of transponders categorized a first transponder and a second transponder; The monitor connected with each of the transponder units, respectively, the monitor monitoring the plurality of transponders and sending a first request and a second request to the plurality of transponders. The first transponder responds an answer to the monitor via the network when the first transponder receives the first request. The second transponder responds an answer to the monitor instead of the first transponder via the network when the first transponder receives the second request.

Abstract: The present invention relates to an optical modulating device with frequency multiplying technique for electrical signals, which primary comprises a mixer, which generates a mixed data signal from a first electrical signal and a second electrical signal. The mixed data signal is then received by a first phase shift device to have its phase shifted and becomes a first shifted signal. The first electrical signal is further received by a second phase shift device to have its phase shifted and becomes a second shifted signal. The present invention further comprises an integrated electro-optic modulator (Mach-Zehnder modulator), which is used to receive an input optical signal, the mixed data signal, the first shifted signal, the second shifted signal and the first electrical signal mentioned above, the integrated electro-optic modulator will then modulates the input optical signal into a frequency multiplying output optical signal that carries the first electrical signal and the second electrical signal.

Abstract: A protocol configuration method for use by a substation to be coupled to a main station in an optical access network is described.

Abstract: The invention provides an optically powered device interface module for operating an external device, and an optically powered data link comprising the same. In one embodiment the device interface module includes an optical interface for receiving optical power and data signals, an electrical USB interface for providing USB compliant electrical data signals and a 5V electrical power signal to an external USB device, a transducer coupled to a signal processor for converting the optical power and data signals into the 5V electrical power signal and the USB-compliant electrical data signals, and a power distribution circuit for providing electrical power obtained from the optical power signal to the device interface module circuitry. The transducer may be embodied using a single photovoltaic power converter for receiving the optical power and for receiving and transmitting optical data signals.

Abstract: An optical power information receiving unit receives optical power information transmitted from a power monitor. When it is judged that a new IT apparatus is connected to an optical switch, an optical switch control unit controls the optical switch to connect the IT apparatus and an optical switch control device. A control device port setting unit changes an IP address of an apparatus information acquiring port based on a control device setting address of an address information storing unit. An apparatus information acquiring unit acquires an IP address of the IT apparatus.

Abstract: The present invention provides an optical power level discriminating device and method for discriminating optical power levels. The optical discriminating device includes a splitter for receiving an optical signal having first and second signal states, and splitting the received optical signal into a first and a second branch optical signal. A first optical fiber for transporting the first branch optical signal is provided that is made of a material having a high non-linear refractive index providing a different non-linear phase shift to the first and second signal states of the first branch optical signal. A second optical fiber is provided for transporting the second branch optical signal with little or no non-linear effect. The discriminating device also includes a combiner for combining the first branch optical signal and second branch optical signal to produce an output optical signal.

Abstract: 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.

Abstract: An apparatus detecting an optical carrier phase difference between adjacent optical pulses structuring an OTDM-DPSK signal, by generally-used optical and electrical elements, is provided. An OTDM-DPSK signal generating section has an optical splitter, a first phase modulator, a second phase modulator, an optical coupler, and a monitor signal branching device, and generates and outputs an OTDM-DPSK signal and a monitor signal. An optical carrier phase difference detecting section has an optical carrier interferometer, and an interference signal detecting section including a optical-to-electrical converter and a peak detection circuit. The monitor signal is inputted to the optical carrier interferometer, and an interference monitor signal is outputted. The interference monitor signal is inputted to the optical-to-electrical converter, and an electrical interference monitor signal is outputted.