Tunable storage of optical data packets modulated in spectrally efficient formats
Thomas Schneider
An all-optical telecommunications network requires all-optical routers. These routers would be able to process optical signals directly, without the transformation to the electrical domain. Thus, optical routers have the potential to accelerate telecommunications, i.e. to enhance the data rate and to minimize the latency times. Furthermore, since the double transformation at each network node can be omitted, they could be able to reduce the energy consumption of telecommunications. Key elements of optical routers are optical buffers, which are able to store the optical packets prior to processing in order to avoid congestion. Therefore, many different concepts for the realization of optical buffers have been presented so far. Most of these can just store or delay on-off keyed (OOK) signals. However, in optical telecommunications advanced modulation formats will be increasingly used because they are able to improve the transmission properties and to take advantage of the capacity of optical fibers. Thus, advanced modulation formats can drastically increase the transmissible data rates. Most of these advanced formats modulate the carrier’s phase or are a combination of amplitude and phase modulation. Here the storage of amplitude and phase modulated data packets with the so called quasi-light-storage (QLS) method will be shown. The QLS relies on the time-bandwidth coherence of each signal. Thus, as long as the sampling theorem in the frequency domain is not violated, a distortion-free storage of optical data packets with a delay-bandwidth product (DBP) of several thousand bits is possible. Here we will discuss the applicability of the QLS method to advanced modulation formats and we show experimental results of the tunable alloptical storage of OOK modulated signals with a DBP of 160 bit and the storage of phase shift keyed signals with a DBP of 60 bits.
Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Mar 6, 2013•0 citations