Abstract: A method for making a pair of photodiodes to detect low-power optical signal includes providing a waveguide including one or more branches in a silicon photonics substrate to deliver an input optical signal to the silicon photonics integrated circuit; forming a pair of nearly redundant photodiodes in silicon photonics platform in the silicon photonics substrate. coupling a first one of the pair of nearly redundant photodiodes optically to each of the one or more branches for receiving the input optical signal combined from all of the one or more branches; coupling a second one of the pair of nearly redundant photodiodes electrically in series to the first one of the pair of nearly redundant photodiodes; and drawing a current from the first one of the pair of nearly redundant photodiodes under a reversed bias voltage applied to the pair of nearly redundant photodiodes.

Abstract: An optical system, comprising: an emitter configured to output a first optical signal along a first optical path to an interference unit and to output a second optical signal along a second optical path to the interference unit, the interference unit being configured to interfere the first and second optical signals, wherein the coherence length of the optical signal is longer than the path difference between first and second optical paths, and there is a path difference between the first and second paths of at least 1 km.

Abstract: Upon receipt of a coherent optical signal that includes a training signal generated using a code sequence constituted by multi-value phase modulation symbols, in which a deviation angle of a vector average of a one-symbol delay differential component of a signal generated on the basis of the code sequence has a prescribed angle and a modulation phase difference between adjacent symbols has a fixed, repeated pattern, a reception training signal corresponding to a training code sequence for frequency offset estimation is detected within a reception signal acquired by converting the received coherent optical signal into an electric signal, a plurality of delay differential components are calculated on the basis of the detected reception training signal and at least two delay signals of the reception training signal, each delay signal having a different number of delay symbols, and an averaged frequency offset amount is calculated using the calculated plurality of delay differential components.

Abstract: A transport network, a node, and a method are disclosed. The transport network, the node, and the method detect a failure of a super channel originating from a sliceable light source that is routed through the transport network, by detecting an optical loss of signal by an optical power monitoring device, in presence or absence of an optical loss of signal of the complete band by at least one photo detector. This information is analyzed with a fault detection algorithm using a patch cable network configuration to determine a fault indication for a failure within the first node. The fault signal indicative of the fault indication is then passed to another node on the first path.

Abstract: There are provided an optical transmission apparatus that subjects a transmission signal including a plurality of sequences to Hadamard transform to obtain a signal in which a predetermined delay is added to one of the sequences, optically modulates the obtained signal, and transmits the modulated signal, and an optical reception apparatus that demodulates a reception signal received from the optical transmission apparatus by subjecting the reception signal to adaptive equalization processing with a predetermined number of taps.

Abstract: An optical communications system including two communications terminals in communication with each other using optical signals having the same wavelength. Both terminals include a half-wave plate polarizer for rotating linearly polarized optical signals and a quarter-wave plate polarizer for circularly polarizing the optical signals. The quarter-wave plate polarizers are oriented 90° relative to each other so that circularly polarized optical signals sent from one terminal to the other terminal are linearly polarized 90° relative to a transmission polarization orientation to be separable from the transmitted optical signals by a beam splitter.

Abstract: A key generation method includes modulating a first key to a first light source signal, to obtain a modulated optical signal, splitting the modulated optical signal, to obtain a first sub modulated optical signal and a second sub modulated optical signal, attenuating the first sub modulated optical signal such that a quantity of photons included in each period of the first sub modulated optical signal is less than a preset value, and sending an attenuated first sub modulated optical signal to a receive-end device, and obtaining a second key carried in the second sub modulated optical signal, and storing the second key.

Abstract: Embodiments of the invention describe polarization insensitive optical devices utilizing polarization sensitive components. Light comprising at least one polarization state is received, and embodiments of the invention select a first optical path for light comprising a first polarization state or a second optical path for light comprising a second polarization state orthogonal to the first polarization state. The optical paths include components to at least amplify and/or modulate light comprising the first polarization state; the second optical path includes a polarization rotator to rotate light comprising the second polarization state to the first polarization state.

Abstract: A Mach Zehnder modulator operates by phase modulating split optical beams with a modulating signal to create dissimilarities in the optical characteristics between the split beams. When the beams are recombined, the dissimilarities gives rise to intensity modulations that are indicative of the modulating signal. One or both beams are modulated with an RF trimming signal. The trimming signal is applied asymmetrically across the two beams thereby reducing the intensity of the optical carrier frequency in one of the beams more than in the other. By selecting the size of the trimming signal the differences in the optical amplitude of the carrier frequency in the two beams can be nulled.

Abstract: A management system configured to manage one or more optical transmitters in an optical network utilizing an optical spectrum, wherein the management system is configured to track at least one of said multiple optical transmitters by specifying a spectral position and spectral width of the portion of the optical spectrum containing a coherent optical signal generated by the at least one optical transmitter, wherein the spectral width is ‘n’ bins where n is an integer greater than 1 and each bin is a same size.

Abstract: An optical full-field transmitter for an optical communications network includes a primary laser source configured to provide a narrow spectral linewidth for a primary laser signal, and a first intensity modulator in communication with a first amplitude data source. The first intensity modulator is configured to output a first amplitude-modulated optical signal from the laser signal. The transmitter further includes a first phase modulator in communication with a first phase data source and the first amplitude-modulated optical signal. The first phase modulator is configured to output a first two-stage full-field optical signal. The primary laser source has a structure based on a III-V compound semiconductor.

Abstract: An apparatus for optical link fault management includes a processor in a network device with an optical adapter of an optical link, and a memory that stores program code. The program code is executable by the processor to store state parameters from the optical adapter in a data log, input the state parameters from the data log into a failure prediction model, and generate, using the failure prediction model, a probability of failure of the optical adapter based on current state parameters from the data log. In response to the probability of failure reaching a failure threshold, the program code is executable by the processor to decrease data traffic in the optical link and to send an alert comprising the probability of failure. The failure threshold includes a probability of failure indicative of impending failure of the optical adapter.

Abstract: An optical receiving device includes a conversion module, a signal generation module and a control module. The conversion module performs photoelectric conversion and amplification on an optical signal to generate a photocurrent, the signal generation module provides a gain signal, performs transimpedance and amplification on the photocurrent according to an input signal indicating a preset output voltage swing to generate a voltage signal, and generates a measurement signal indicating an average optical power associated with the optical signal according to the photocurrent, the control module outputs a control signal which is variable to adjust a gain of the conversion module, so that a dynamic range of the conversion module changes as the gain of the conversion module itself changes.

Abstract: To provide an optical transmitter and an optical transmission method that can maintain the quality of an optical output signal in a wide wavelength range, an optical transmitter comprises: an optical modulator that includes an electrode and outputs an optical output signal obtained by modulating input light according to a drive signal applied to the electrode; a driver circuit that generates a drive signal and is connected to the optical modulator to apply a drive signal to one end of the electrode; a first element that is connected to the other end of the electrode and terminates the drive signal; and a controller that sets a first resistance value of the first element and a drive amplitude of the drive signal.

Abstract: A method for communicating from a transceiver including a sub-transceiver array includes setting the sub-transceiver array to emit an optical signal at an initial pointing angle, and modifying at least one of the sub-transceivers to emit a first optical sub-signal at a first pointing angle having a first offset from the initial pointing angle. The method further includes, during a first transmit period, transmitting to a receiving transceiver from the sub-transceiver array a first optical signal including the first optical sub-signal, at a first data rate. The method also includes further modifying the sub-transceiver to emit a second optical sub-signal at a second pointing angle having a second offset from the initial pointing angle, the second offset being smaller than the first offset, and, in a second transmit period, transmitting to the receiving transceiver from the sub-transceiver array a second optical signal including the second optical sub-signal.

Abstract: Disclosed herein are techniques, methods, structures and apparatus that provide a silicon photonics multicarrier optical transceiver wherein both the transmitter and receiver are integrated on a single silicon chip and which generates a plurality of carriers through the effect of an on-chip modulator, amplifies the optical power of the carriers through the effect of an off-chip amplifier, and generates M orthogonal sets of carriers through the effect of an on-chip basis former.

Abstract: The invention discloses a fabrication process variation analysis method of a silicon-based Mach-Zehnder electro-optic modulator. The method includes the following steps: (1) use the input reflection coefficient S11 to characterize and quantify the reflection deviation characteristics of the driving signal on the traveling wave electrode; (2) measure and quantify the modulated signal characteristics of the silicon Mach-Zehnder electro-optic modulator. The modulated signal characteristics include transmission characteristics, vertical direction characteristics and horizontal direction characteristics; (3) Pearson correlation coefficient and partial correlation coefficient are introduced. By analyzing the value and variation trend of Pearson correlation coefficient and partial correlation coefficient, the relationship between the deviation of the driving signal reflection and the deviation of the modulated signal characteristics is analyzed.

Abstract: A transmitter, receiver and transceiver system that may be used for both transmitting and receiving modulated signals are disclosed. The system includes an Electrical-to-Optical (E2O) converter that receives a Radio Frequency (RF) signal and transmits an optical signal and/or an Optical-to-Optical (O2O) that performs a wavelength translation from one wavelength to another wavelength. The Electrical-to-Optical (E2O) converter includes a vapor cell that converts the RF signal to an optical signal.

Abstract: A coupling module can be used to communicate high speed signals between an optical transceiver and a processing module of an optical communication device, such as an optical line termination (OLT) or an optical network unit (ONU). The coupling module can adjust the common mode voltage level of a differential signal output by the optical transceiver to the common mode voltage level required by the processing module. In addition, the coupling module splits each of the differential output signals from the optical transceiver and passes the split signals to both a high-pass filter and a low-pass filter that are connected in parallel. An adapter module can be connected to the coupling module such that the coupling module can receive different differential signals from different optical transceivers.

Abstract: An approach for pre-distorting an input signal for an optical transmitter so as to at least partially compensate in advance for linear and non-linear distortions of the optical transmitter is provided.