Polarization Insensitive One-to-Six WDM Multicasting in a Silicon Nanowire

Abstract

Abstract:We present polarization insensitive one-to-six WDM multicasting based on nondegenerate four-wave mixing in a silicon nanowire with angled-pump scheme. Bit-error rate measurements are performed and error-free operation is achieved. IntroductionMulticasting is an important feature in a communication network, which can efficiently send a stream of information from a single source to multiple destinations [1], [2]. By using multicasting technology, the amount of network resources can be significantly reduced compared to unicast only networks. Optical layer multicasting could be implemented at a fixed wavelength by power splitting. An alternative is optical wavelength division multiplexing (WDM) multicasting, i.e., multicasting to different wavelengths. One of the most addressed techniques for WDM multicasting is all-optical multi-wavelength conversion (MWC), which replicates signals from one wavelength on multiple wavelengths. WDM multicasting has been demonstrated in different devices including semiconductor optical amplifiers (SOAs) Recently, wavelength conversion in silicon nanowires has attracted considerable research interest due to its compactness, large conversion bandwidth [7] and complementary metal-oxide-semiconductor (CMOS) compatibility. Silicon nanowires have been utilized to demonstrate wavelength conversion at data rates from 10 Gb/s [8] to 640 Gb/s [9], and a sixteen-way multicasting operation of 40 Gb/s non return-to-zero (NRZ) data has also been demonstrated in silicon nanowires [10]. However, sixteen continuous wave (CW) tunable laser sources (TLSs) are needed to act as input signals and phase information is not preserved in the converted signals. Previously, we have demonstrated one-to-six multicasting operation based on dual-pump FWM in a silicon nanowire [11]. The FWM process is normally highly polarization dependent and an efficient FWM process only occurs when the input signal and pump waves are both aligned to either transverse-electric (TE) mode or transverse-magnetic (TM) mode. However, a polarization insensitive operation is desired since the state of polarization (SOP) of the input signal fluctuates with time and distance in a real transmission system.[In this paper, we report polarization-insensitive one-to-six WDM multicasting of 10 Gb/s differential phaseshift-keying (DPSK) data based on dual-pump FWM in a silicon nanowire using an angled-pump scheme [12]. Error-free performance is achieved for all six multicast signals while the polarization of the input data signal is continuously scrambled.