Abstract: A key storage device comprises a one-way receiving interface, a key calculation unit, and a one-way outputting interface. The key calculation unit includes a signature unit. The one-way receiving interface receives a transaction message of an external electronic device in a single direction. The signature unit encrypts the transaction message by a private key to generate a signature message. And, the one-way outputting interface transmits the signature message to the external electronic device in a single direction.

Abstract: An apparatus for enabling a passive optical network (PON) having an OLT and at least one ONU on supporting time synchronization is disclosed. The apparatus comprises a timestamp correction module configured to make at least one network delay between the OLT and the at least one ONU of the PON equivalent to an equivalent path delay, wherein the timestamp correction module, through the PON, makes the at least one ONU responsible for modifying the timestamp in at least one PTP packet from the OLT, so that a slave clock at the backend of the at least one ONU is equivalent to synchronizing with a virtual master clock. The disclosure computes and corrects PTP commands so that the PTP clock at an ONU's backend may synchronize precisely with the master clock at an OLT's front end.

Abstract: An apparatus for enabling a passive optical network (PON) having an OLT and at least one ONU on supporting time synchronization is disclosed. The apparatus comprises a timestamp correction module configured to make at least one network delay between the OLT and the at least one ONU of the PON equivalent to an equivalent path delay, wherein the timestamp correction module, through the PON, makes the at least one ONU responsible for modifying the timestamp in at least one PTP packet from the OLT, so that a slave clock at the backend of the at least one ONU is equivalent to synchronizing with a virtual master clock. The disclosure computes and corrects PTP commands so that the PTP clock at an ONU's backend may synchronize precisely with the master clock at an OLT's front end.

Abstract: An apparatus and method for simultaneous channel and optical signal-to-noise ratio (OSNR) monitoring is adapted to function in multi-channel wavelength-division-multiplexed (WDM) optical communication systems. A polarization controller is sequentially adjusted to perform the sequential polarization control with an optical signal. A polarization-selective electro-optic modulator acts as a polarizer and provides a signal dithering to improve the detection sensitivity. A beam splitter splits the dithered optical signal into two clusters. A photodetector receives the first cluster and measures the OSNR. An optical element receives the second cluster and monitors the channel wavelength of multiple channels. The apparatus can be packaged into a compact module and integrated on a chip. The channel monitoring covers a wide wavelength range and is tunable. The OSNR monitoring can be accurate over a wide dynamic range.

Abstract: An apparatus and method for simultaneous channel and optical signal-to-noise ratio (OSNR) monitoring is adapted to function in multi-channel wavelength-division-multiplexed (WDM) optical communication systems. A polarization controller is sequentially adjusted to perform the sequential polarization control with an optical signal. A polarization-selective electro-optic modulator acts as a polarizer and provides a signal dithering to improve the detection sensitivity. A beam splitter splits the dithered optical signal into two clusters. A photodetector receives the first cluster and measures the OSNR. An optical element receives the second cluster and recognizes the channel wavelength of multiple channels. The apparatus can be packaged into a compact module and integrated on a chip. The channel monitoring covers a wide wavelength range and is tunable. The OSNR monitoring can be accurate over a wide dynamic range.