Synchronization, retiming and time-division multiplexing of an asynchronous 10 Gigabit NRZ Ethernet packet to terabit Ethernet

Abstract

An asynchronous 10 Gb/s Ethernet packet with maximum packet size of 1518 bytes is synchronized and retimed to a master clock with 200 kHz frequency offset using a time lens. The NRZ packet is simultaneously converted into an RZ packet, then further pulse compressed to a FWHM of 400 fs and finally time-division multiplexed with a serial 1.28 Tb/s signal including a vacant time slot, thus forming a 1.29 Tb/s time-division multiplexed serial signal. Error-free performance of synchronizing, retiming, time-division multiplexing to a Terabit data stream and finally demultiplexing back to 10 Gb/s of the Ethernet packet is achieved.

Optical Systems for Ultra-High-Speed TDM Networking

“…The key functionality of optical data synchronization is demonstrated in [9,10]. The scheme for optical data synchronization relies on carefully applying a timing-dependent phase modulation to the individual data bits and subsequently adjusting their relative timing using a dispersive element.…”

320 Gb/s Nyquist OTDM received by polarization-insensitive time-domain OFT

“…One solution is to use optical spectral slicing with parallel coherent detection using an optical frequency comb (OFC) as local oscillator [18,19]. Another option is to convert the time-domain signal into frequency domain using time-domain optical Fourier transformation (TD-OFT) and extract each tributary using optical bandpass filters (OBFs) [20][21][22][23][24]. An advantage of using OBFs instead of time-domain optical gates is that the extracted signal already has a narrow spectrum and won't experience additional filtering losses, due to the narrow filter, before it's launched into a base-rate optical receiver.…”

“…The N-OTDM signal eyediagram appears to be distorted due to the overlapping of neighboring channels as a result of the narrow filtering; however at the centre of each bit slot (white circle) inter-channel interference (ICI) is absent due to the sinc shape of the Nyquist filtered pulses. The concept of the TD-OFT stems from the space-time duality between diffractive propagation of spatial light beams and dispersive propagation of temporal optical pulses [20][21][22][23][24]. Since a spatial lens can be employed to achieve a spatial Fourier transformation of an object placed at the front focal plane, a time lens can also be used to achieve a time-domain Fourier transformation of a temporal profile.…”

“…The time lens equivalent of a spatial lens is a quadratic phase modulation as a function of time. This can be achieved using an E/O phase modulator [22] or a four-wave mixing (FWM) process [23,24]. The FWM process can provide larger quadratic phase-modulation than the E/O phase modulator.…”