Optical interconnection of core and metro networks [Invited]

Abstract

͑Doc. ID 99278͒A network concept is introduced that exploits transparent optical grooming of traffic between an access network and a metro core ring network. This network is enabled by an optical router that allows bufferless aggregation of metro network traffic into higher-capacity data streams for core network transmission. A key functionality of the router is WDM to time-division multiplexing (TDM) transmultiplexing.

Field Experiments With a Grooming Switch for OTDM Meshed Networking

“…Any process of WDM-to-OTDM mapping should involve the following: (i) narrowing of the lower bit-rate time-slot in order to fit the OTDM time-slot; (ii) converting the lower bitrate wavelengths into a common wavelength; (iii) retiming these lower bit-rates [17]. The retiming function concerns the translation of the input signal frequency (or bit-rate), f D , to a frequency determined by a shared node-specific local clock, f L .…”

“…This involves both synchronizing the tributary data rates -since data rates are different for tributaries that are generated at different, remote locations -and phase aligning the pulses. An effective solution to this problem had not been reported until very recently [17] when the asynchronous digital optical regeneration (ADORE) concept [18], [19] was applied to OTDM/WDM networks (i.e. with the retiming applied at tributary level).…”

Time-division-multiplexing using pulse position locking for 100 Gb/s applications

“…The selected signal was amplified by an erbium doped fiber amplifier (EDFA)-preamplifier (noise figure 5 dB) and detected using a 32 GHz bandwidth optical PIN receiver. We evaluated the performance in terms of eye opening, defined as 20log 10 [ (U 1min -U 0max )/(u 1 -u 0 )], where U 1min is minimum value of "ones", U 0max is maximum value of "zeros", u 1 , u 0 are the respective mean values. An eye opening penalty (EOP) was obtained by normalising the eye opening to the input signal.…”

“…However, they all require low jitter clock recovery circuits. For optical networks based on burst/packet transmission, asynchronous retiming has been proposed [8] and demonstrated [9,10]. However, this approach fundamentally samples temporally broadened signal pulses dramatically reducing the efficiency of the device.…”

A dual purpose, all optical multiplexer circuit in InP, for multiplexing clock and NRZ data, and for transmultiplexing WDM to TDM

“…In its turn the MAN TDM channel is one of the constituent channels of a MAN WDM comb. In the literature, a network concept that exploits this transparent grooming of traffic between access network and a metro core ring network is described in ref [1]. Whereas a regenerative optical grooming switch for buffer-less interconnection of metro/access and metro/core ring networks is demonstrated in [2].…”