Next-generation photonic networks

摘要

Novel network architecture and key device technology are described for next-generation photonic networks enabling high-performance data communications. To accomplish full-mesh links for efficient data transportation, time-shared wavelength-division multiplexing (WDM) is the most promising under the limitation imposed on the total wavelength number available at network nodes. Optical add/drop multiplexing (OADM) using wavelength-tunable devices is essential for temporal data link formation. Wavelength management based on absolute wavelength calibration is a key to OADM operations. A simple wavelength discriminating device using a disk-shaped tunable optical bandpass filter under the synchro-scanned operation is useful for managing the laser wavelengths. High-speed data transmissions of >40Gbps necessary for efficient operation of the networks are also described. A key is photonic downconversion which enables phase detection for optical data streams at above the electrical limitation of around 50 GHz. This technique is applied not only to a phase-locked loop for synchronizing mode-locked pulses to an electrical signal in the much lower frequency range of around 10 GHz, but to timing extraction from 100-Gbps data streams.