Embodiment herein provides an Infrastructure article (101) and method thereof for synchronizing blinks of infrastructure articles in a mesh network. The method includes detecting an expiry of a sync timer counted by a real time clock (RTC) and determining whether a charge level of a battery (105) of the infrastructure article (101) meets a battery charge threshold. When the charge level of the battery (105) of the infrastructure article (101) meets the battery charge threshold, the method includes establishing a connection with other infrastructure article and/or an infrastructure article server (200) in the mesh network, and sending a time to synchronize blink of the at least one light source (106) to all other infrastructure articles in the mesh network. When the charge level of the battery (105) of the infrastructure article (101) does not meet the battery charge threshold, the method includes resetting the sync timer, and initiating a count of the sync timer.

A multipurpose accessory and storage system for an electronic device includes a housing member attaching to the electronic device and a charging station structured on the housing member to charge, arrest and dispense an accessory item. The accessory item includes a protective membrane housing a logic board, a power component, an image sensor, a transmitter configured to transfer a signal or data to the electronic device or the housing member and a software program stored in the logic board. The transmitter establishes a pairing or electronic connection between the electronic device or the housing member and the accessory item. The pairing or electronic connection enables content captured by the image sensor to be relayed to the electronic device to permit a user to view the content on the display of the electronic device and/or to control components and features of the accessory item via the electronic device.

An optically powered Global Navigation Satellite System (GNSS) antenna may use a fiber-optic link to receive optical power and transmit an optical signal that contains a common time signal from one or more satellites, which may allow long-distance power and signal transmission with high efficiency and reliability. The common time signal may be used to synchronize intelligent electronic devices (IEDs) of an electric power delivery system.

A system includes, in part, a first optical modulator adapted to modulate a first optical signal with a first data to generate a first modulated optical signal, a second optical modulator adapted to modulate a second optical signal with a first clock signal to generate a second modulated optical signal, an optical multiplexer adapted to multiplex the first and second optical signals to generate a multiplexed optical signal, and an optical fiber adapted to carry the multiplexed optical signal. The second optical signal has a second wavelength that is different from the first wavelength.

The present disclosure provides an optical communication drive circuit and method, an optical communication transmitter, an optical communication system, and a vehicle. The optical communication drive circuit includes a clock circuit and a modulation circuit. The clock circuit is configured to output a clock signal with an initial frequency signal as an input under control of information to be transmitted. The clock signal includes alternating first and second frequency signals, the first frequency signal and the second frequency signal having different frequencies and being generated based on the initial frequency signal; and the modulation circuit is configured to modulate an optical signal by the clock signal to obtain a modulated optical signal.

A low-jitter digital clock signal generating system which uses optical pulses output from a pulse laser includes a first balanced photodetector that converts first and second optical pulses with a delayed time interval into first and second electrical pulses through first and second photodiodes and outputs first and second modulated pulses generated by allowing the first and second electrical pulses to partially overlap each other, a second balanced photodetector that converts third and fourth optical pulses with the delayed time interval into third and fourth electrical pulses through third and fourth photodiodes, and outputs a second modulated pulse generated by allowing the third and fourth electrical pulses to partially overlap each other, and a capacitor. The capacitor is charged by the first modulated pulse, is discharged by the second modulated pulse, and outputs a voltage according to the charging and discharging as a clock signal.

An optically powered Global Navigation Satellite System (GNSS) antenna may use a fiber-optic link to receive optical power and transmit an optical signal that contains a common time signal from one or more satellites, which may allow long-distance power and signal transmission with high efficiency and reliability. The common time signal may be used to synchronize intelligent electronic devices (IEDs) of an electric power delivery system.

A system for generating clock signals for a photonic quantum computing system includes a pump photon source configured to generate a plurality of pump photon pulses at a first repetition rate, a waveguide optically coupled to the pump photon source, and a photon-pair source optically coupled to the first waveguide. The system also includes a photodetector optically coupled to the photon-pair source and configured to generate a plurality of electrical pulses in response to detection of at least a portion of the plurality of pump photon pulses at the first repetition rate and a clock generator coupled to the photodetector and configured to convert the plurality of electrical pulses into a plurality of clock signals at the first repetition rate.

[Problem] To synchronize timings of transmitting and receiving a pulse signal (1 PPS signal) at a constant interval between communication apparatuses even in a case where an optical fiber connecting the communication apparatuses fluctuates in an optical characteristic and an optical fiber length.

[Solution] The time synchronization system 20 transmits and receives a pulse signal at a constant interval between a local apparatus L (apparatus L) and a remote apparatus R (apparatus R) connected through the two-core bidirectional optical fibers F1 and F2 to synchronize time. A propagation delay amount 1 in the fiber F1 is calculated, from a proportional relationship between T1 and T2 and a proportional relationship of ud and 1, where T1 represents a propagation delay time difference between a pulse signals P1 and P4 of an identical wavelength .sub.1 returned after transmitting a pulse signal P1 of wavelength .sub.1 and a pulse signal P2 of wavelength .sub.2 different from .sub.1 to the remote apparatus R, T2 represents a propagation delay time difference between the pulse signal P1 of wavelength .sub.1 and a pulse signal P3 of wavelength .sub.2, and ud represents the round-trip delay time between the apparatuses L and R. The pulse signals P1 and P2 are transmitted with a time difference td corresponding to a difference between the current and last calculated propagation delay amounts 1 being set so that the difference is zero.

In an aspect, an apparatus for distribution of frequency reference to a receiving end over a transmission medium comprises a first mixer adapted to mix a frequency reference signal having a reference frequency with a local oscillator signal having a local oscillator frequency to provide a forward frequency reference signal, a communication section adapted to transmit the forward frequency reference signal and receive a first backward frequency reference signal, a second mixer adapted to mix the first backward frequency reference signal with the local oscillator signal to provide a second backward frequency reference signal and a phase comparator and control circuit adapted to adjust the local oscillator frequency based on a phase shift of the second backward frequency reference signal so as to compensate for a phase shift of the forward frequency reference signal.