Optical orthogonal frequency division multiplexing using frequency/time domain filtering for high spectral efficiency up to 1 bit/s/Hz

Abstract

400-channel25-GHz spacing arrayed-waveguide grating COYering a full range of C-and L-bands? OFC 5. M. 1shii.A.Takaei.Y. Hida. M. Itoh. S. Kamei. 2001, Anaheim, WBZ, zoni. cascaded spot-size converter" OECCIIOOC 6 . M. 1toh.T. Saida,Y. Hida, M. 1shii.Y. Inoue,Y. 0 Z N 1 , Sydney, PDt-I, 2001. 0 32 64 96 128 160 192 224 256Hihino. and A. Sueita. 'Low-loss 1.5% A ar-Channel numbsr " rayed waveguide grating with spot-size converters," ECOC '01. Amsterdam, Mo.F.2.3, ThC6 Fig. 7. Losses of 256-channel AWG chip and module after packaging. 2001.Himena andY. Ohmori,"Fabrication of very spectral efficiency has been limited. In this paper, we propose and experimentally demonstrate a novel scheme for WDM systems to overcome the spectral efficiency limitation. It is well known that orthogonal frequency division multiplexing provides high spectral efficiency in a wireless communication system.' However, the complicated demultiplexkg scheme, mostly digital processing, is difficult to use in the optical frequency domain. Our proposed scheme applies this concept to an optical communication field. We also propose the use of an optical discrete Fourier transformer to accomplish separation. The transformer is implemented by filtering the neighboring signals in the time and frequency domains. The scheme allows theoverlap ofthespectrumofneighboringchannels and can eliminate the coherent crosstalk

Approaching the Non-Linear Shannon Limit

“…It is clear that any required guard band between WDM channels reduces the ISD. The guard bands may be avoided by employing orthogonal frequency division multiplexing (OFDM) techniques [19,20], such as no-guard-interval OFDM [21][22][23], coherent WDM [24][25][26][27] direct detection OFDM [28,29] and coherent optical OFDM [30][31][32][33][34][35] In all of these multi-carrier systems, the frequency spacing between the orthogonal sub-carriers is equal to the symbol rate per subcarrier. A typical example of the orthogonal carriers are shown in figure 8, where the peak of the spectrum of a given channel corresponds to nulls in the spectra of all of the other sub-channels, and in particular, the first null in the spectrum of the adjacent sub-channel.…”

A Survey on OFDM-Based Elastic Core Optical Networking

“…In its turn, the receiver demultiplexes each optical subcarrier by an all-optical DFT processor, which can be implemented by adding phase delays and careful arrangement of time delays in each subcarrier [36], as depicted in Fig. 8(b).…”

All-optical OFDM and distributed Raman amplification: Challenges to enable high capacities and extend reach

“…The demonstration of all-optical OFDM in single mode fibre was first seen in 2002 7 , where the concepts from wireless communications were transferred to the optical domain with the aid of an optical discrete Fourier  now with Nokia Siemens Networks Portugal, S.A., Lisbon, Portugal transformer based on asymmetric Mach-Zehnder interferometers. This work was followed by the experimental demonstration of Coherent WDM 8 , where it was shown that, even without ideal matched filters, the phase between adjacent subcarriers at the transmitter could be carefully adjusted to preserve orthogonality.…”