Semiconductor Optical Amplifier-Based Wavelength Conversion of Nyquist-16QAM for Flex-Grid Optical Networks

Abstract

Abstract-We experimentally demonstrate semiconductor optical amplifier (SOA) based wavelength conversion of 3×25 Gbaud Nyquist-16QAM signal for a flex-grid network. The conversion efficiency and power penalty of each of three channels during single pumped SOA wavelength conversion are studied with respect to three different channel spacings (or frequency grids). The BER performance of all converted channels fall below the FEC threshold of 3.8e-3, even with a 50 GHz grid. The results show the tradeoff between channel spacing, conversion efficiency and BER power penalty. Closely packed channels, which clearly increase spectral efficiency, are also shown to decrease conversion power penalty, potentially counter balancing increased crosstalk levels. These results can be used to optimize routing and spectrum allocation strategy when SOA wavelength converter(s) are present in the optical link.

Microwave photonics‐based all optical wavelength conversion of Nyquist‐DP‐16QAM for flex‐grid optical networks with 112 Gbps

“…In Ref., the SOA is adopted in the process of wavelength conversion, the authors find that it will increase the OSNR penalty when the smaller frequency spacing is employed, they study the relationship between the OSNR penalty and the channel frequency spacing and, they make a contribution about optimization of the flex‐grid. However, from Figure , many channels with good BER and accepted OSNR can be obtained when the different channel frequency spacing is adopted.…”

“…Consequently, we can get the good BER below FEC threshold when these channels with larger optical power are used for optical transmission, then the wavelength conversion in the optical networks is very helpful to select suitable channel and optimize the flex-grid. In Ref., 19 the SOA is adopted in the process of wavelength conversion, the authors find that it will increase the OSNR penalty when the smaller frequency spacing is employed, they study the relationship between the OSNR penalty and the channel frequency spacing and, they make a contribution about optimization of the flex-grid. However, from Figure 6, many channels with good BER and accepted OSNR can be obtained when the different channel frequency spacing is adopted.…”

“…It is an advantage that the SOA is not employed in wavelength conversion; therefore, we need not study the nonlinear effect of the SOA that effect on the OSNR penalty. The channel CE of the SOA is defined by the ratio of the output optical power to the input optical power, and we also need not to research the problem of CE due to SOA none employed in our design. Nevertheless, the optical power of the converted wavelength can be increased via the EDFA (as shown in Figure ), i.e.…”

“…It is easy to support the flex‐grid network for Nyquist‐WDM. Consequently, SOA based AOWC of Nyquist‐16QAM in an optical flex‐grid network is proposed and, BER below the forward error correction (FEC) threshold of 3.8 × 10 −3 for all three converted channels is demonstrated . However, in the process of the wavelength conversion, the employment of SOA will greatly reduce the OSNR and seriously debase the transmission quality of the signal, and the number of the selectable converted wavelength is very limited.…”

“…Consequently, SOA based AOWC of Nyquist-16QAM in an optical flex-grid network is proposed and, BER below the forward error correction (FEC) threshold of 3.8 × 10 −3 for all three converted channels is demonstrated. 19 However, in the process of the wavelength conversion, the employment of SOA will greatly reduce the OSNR and seriously debase the transmission quality of the signal, and the number of the selectable converted wavelength is very limited. Ones know that the modulation of Nyquist multi-carrier has better nonlinear tolerance and lower peak to average power ratio (PAPR) than orthogonal frequency division multiplexing (OFDM) modulation.…”