A Survey on OFDM-Based Elastic Core Optical Networking <s> 1) Data-Rate/Bandwidth-Variable Transponder <s> We demonstrated, for the first time, a novel spectrum-efficient elastic optical path network for 100 Gb/s services and beyond, based on flexible rate transceivers and variable-bandwidth wavelength crossconnects. <s> BIB001 </s> A Survey on OFDM-Based Elastic Core Optical Networking <s> 1) Data-Rate/Bandwidth-Variable Transponder <s> We propose and demonstrate a bit-rate-flexible all-optical OFDM transceiver. Signals were successfully generated at 107, 42.8, 32.1, and 10.7Gbit/s and received through the transceiver. The 107-Gbit/s signal was successfully transmitted over 40-km-SMF without dispersion compensation. <s> BIB002 </s> A Survey on OFDM-Based Elastic Core Optical Networking <s> 1) Data-Rate/Bandwidth-Variable Transponder <s> Motivated by the design goals of Global Environment for Network Innovation (GENI), we consider how to support the slicing of link bandwidth resources as well as the virtualization of optical access networks and optical backbone mesh networks. Specifically, in this paper, we study a novel programmable mechanism called optical orthogonal frequency division multiplexing (OFDM)/orthogonal frequency division multiple access (OFDMA) for link virtualization. Unlike conventional time division multiplexing (TDM)/time division multiple access (TDMA) and wavelength division multiplexing (WDM)/wavelength division multiple access (WDMA) methods, optical OFDM/OFDMA utilizes advanced digital signal processing (DSP), parallel signal detection (PSD), and flexible resource management schemes for subwavelength level multiplexing and grooming. Simulations as well as experiments are conducted to demonstrate performance improvements and system benefits including cost-reduction and service transparency. <s> BIB003
The data-rate/bandwidth-variable transponder is capable of supporting multiple data rates from sub-wavelength to superwavelength. In order to achieve high spectral resource utilization, the data-rate/bandwidth-variable transponder needs to generate an optical signal using just enough spectral resources, according to the client data rate and the channel conditions. A variety of schemes can be used to support these features, as described below. a) Subcarrier Number Adjustment Data rate/bandwidth-variable sub-wavelength services can be provided by adjustment of the number of OFDM subcarriers in the transponder. The control of the subcarrier number can be performed in the optical or digital domain, depending on what kind of signal synthesis method is used (see Section III-A). The granularity of adjustment corresponds to the data rate of each subcarrier, as illustrated in Fig. 13 . For O-OFDM systems employing the optical subcarrier synthesis scheme, the data-rate/bandwidth-variable transponder consists of a variable optical multi-carrier source and an optical multi-carrier modulator. The number of subcarriers is controlled by adjusting a continuous-wave light with different oscillator frequencies. In BIB001 , a data-rate/bandwidth-variable transponder that supports bit rates from 40 to 440 Gb/s, with 10 Gb/s granularity and 10 GHz subcarrier spacing was experimentally demonstrated. Likewise, BIB002 demonstrated an For FFT-based O-OFDM technology, the number of subcarriers can be adjusted in the electrical domain, or the number of bands can be adjusted in the optical domain for the multi-band OFDM scheme. In BIB003 , a 10 Gb/s OFDM signal generation with 256 subcarriers was demonstrated, with an adjustment granularity of 40 Mb/s.