Abstract: An optical power control device includes a controller configured to: obtain a received waveform of a WDM optical signal transmitted between a plurality of transmission devices via a transmission path, and calculate a power profile of a distance direction of the transmission path based on the received waveform; and calculate a nonlinear SNR of the transmission path based on the power profile.

Abstract: A transmission path monitoring apparatus includes a memory configured to store an electric field signal that indicates an optical electric field component of an optical signal received from the optical transmission path, and a processor configured to generate predetermined information that includes optical powers of the optical signal at positions over the optical transmission path, based on the electric field signal and a specific signal that indicates an electric field and is obtained from demodulated data based on the electric field signal, and update the predetermined information, based on a first error between the electric field signal after compensating for linear distortion of the optical signal and nonlinear distortion of the optical signal based on the predetermined information and the specific signal, and a second error between differential amounts of the optical power at the positions and a reference value that includes a transmission loss of the optical transmission path.

Abstract: A transmission line parameter estimation apparatus includes: a storage unit configured to stores in advance a non-linear phase rotation amount distribution obtained by using time waveform data acquired from a receiver, of a first transmission line, and a non-linear phase rotation amount of a second transmission line different from the first transmission line; and a controller configured to refer to data in the storage unit, and obtains a non-linear constant of each span of the second transmission line based on a distribution of the non-linear phase rotation amount.

Abstract: A method may include obtaining a first waveform corresponding to a first optical signal received at a first optical receiver via an optical link, and a second waveform profile corresponding to a second optical signal received a second optical receiver. The first waveform profile and the second waveform profile may be combined to form a combined waveform profile. A first reconstructed waveform profile that is an estimate of the first waveform profile and a second reconstructed waveform profile that is an estimate of the second waveform profile may be obtained. The first reconstructed waveform profile and the second reconstructed waveform profile may be combined to form a combined reconstructed waveform profile which may be emulated to obtain an emulated reconstructed waveform profile. A power profile estimation corresponding to the optical ink may be determined based on a comparison between the combined waveform profile and the emulated reconstructed waveform profile.

Abstract: A control method executed by a computer, the control method includes: generating, when specification of a first data table constituting data to be retrieved is received, a data table copy that is a copy of the first data table, and switching the data to be retrieved, from the first data table to the data table copy; and performing a data retrieval process with respect to the data table copy, by controlling any one of a number of the data to be retrieved from the data table copy and a data retrieval interval, based on a load state estimated from a result of the data retrieval process.

Abstract: According to an aspect of an embodiment, operations may include obtaining a first waveform profile corresponding to an optical signal received at an optical receiver via an optical link between the optical receiver and an optical transmitter. The operations may also include obtaining a second waveform profile that is an estimate of the first waveform profile. The second waveform profile may be based on one or more properties of the optical link and may be based on a complex scaling factor that accounts for rotation of the optical signal as the optical signal propagates via the optical link. In addition, the operations may include determining a power profile estimation corresponding to the optical link based on a comparison between the first waveform profile and the second waveform profile.

Abstract: A control method implemented by a computer configured to control a database that includes an aggregate item that records an aggregate value of transaction volume included in transaction data recorded in a blockchain, the control method including: obtaining a plurality of the transaction data recorded in the blockchain; specifying, for each of a plurality of second users who are transaction partners with a first user associated with the aggregate item, a transaction time with the first user on a basis of the plurality of transaction data; classifying the plurality of second users into a plurality of groups on a basis of dissimilarity of the transaction time; and generating the aggregate item for each of the groups in the database.