Polarization-Insensitive and Receiver-Sensitivity-Gain Format Conversion for PDM Signals Based on Dual-Orthogonal-Pump Four-Wave Mixing in Highly Nonlinear Fiber

Abstract

All-optical format conversion plays an important role in future transparent optical networks in order to enhance reconfigurability. On the other hand, the polarizationdivision multiplexing (PDM) technique has been extensively studied for achieving high-speed and high-spectral-efficiency optical networks. Since the state of polarization of PDM signals are randomly changed along the transmission optical link, it is important to elaborately design a polarization-insensitive conversion scheme in such a network. In this paper, we proposed and experimentally demonstrated an all-optical nonreturn-to-zero-return-to-zero format conversion for PDM on-off keying (OOK), binary phase-shift keying (BPSK), and quadrature phase-shift keying (QPSK) signals. Polarization-insensitive operation is achieved by utilizing the merit of the dualorthogonal-pump four-wave mixing (FWM) process in a highly nonlinear fiber, and receiver-sensitivity-gain operation is observed in the conversion process. The bit error ratio (BER) results show that receiver-sensitivity gains of $1.5, $0.8, and 0.3 dB for the OOK, BPSK, and QPSK PDM signals at BER values of 10 À9 , 10 À9 , and 10 À3 are obtained, respectively.Index Terms: Format conversion, polarization division multiplexing (PDM), four-wave mixing (FWM), highly nonlinear fiber (HNLF).

Dual-pumped nondegenerate four-wave mixing in semiconductor laser with a built-in external cavity

“…Hence, the power peaks of the pump and signal waves drop as a result of the enhanced power of the converted signals, and the frequency spacing between the input signal and resulting converted waves corresponds to a conversion range that can reach as wide as more than 3 THz by changing the wavelength of one pump wave. In addition, although the technology regarding the dual-pumped FWM process, based on semiconductor optical amplifiers, fibers and silicon waveguides, has already been reported in previous literature [2,4,6,10,[36][37][38][39], the achieved results in this work still have some prominent characteristics, such as low power consumption and a broadly tunable conversion bandwidth, making the process strongly competitive in FWM-based technology.…”

“…Over the last decades, four-wave mixing (FWM), which is an important effect in nonlinear optics, originating from the third-order nonlinear susceptibility of optical media, has been intensively presented and investigated in many promising optical elements such as silicon-based waveguides [1][2][3], nonlinear optical fibers [4][5][6][7][8][9], semiconductor optical amplifiers [10][11][12][13], semiconductor lasers [14][15][16][17] and other nonlinear waveguides [18][19][20]. It is well known that the nonlinear FWM effect gives rise to some serious limitations, such as crosstalk in dense wavelength division multiplexing (DWDM) technology [21], etc, and needs to be effectively suppressed to increase the potential capacity of optical communications.…”

Simultaneous Wavelength and Format Conversions Based on the Polarization-Insensitive FWM in Free-Space Optical Communication Network

“…By facilitating the full utilization of the bandwidth of laser carriers [8], [9], the WC-OCS can enhance the interoperability and reduce the blocking probability of the FSO network. Nevertheless, the FSO network requires the WC-OCS should be modulation format independent to support a wide diversity of missions, and also be capable of format conversion when the atmospheric channel conditions change [10], [11]. Four-wave mixing (FWM) process in nonlinear fiber is preferentially selected to perform all the above mentioned operations because of its transparency to the bit rate and the modulation format [12]- [14], as well as its capability of modulation formats conversion from M-ary PSK to M/2-ary PSK based on the inherent phase erasure effect [15]- [17].…”