Low-Loss Optical Nyquist Pulse Train Generation Using Nonauxiliary Wavelength Selective Switch in Communication Band

Abstract

We report low-loss optical Nyquist pulse train generation using a non-auxiliary wavelength selective switch (WSS). The typical approach for optical Nyquist pulse train generation involves two procedures. The first is conversion from a laser output Gaussian pulse to a Nyquist pulse via spectral filtering with a WSS. The second is multiplexing to generate a Nyquist pulse train with an optical circuit. To generate a high optical signal-tonoise ratio (OSNR) Nyquist pulse train, the first procedure was improved by developing a high-power laser and improving the filtering process by using nonlinear effects in a highly nonlinear fiber. The second procedure also has the potential to further improve the OSNR, because an optical circuit typically causes an optical loss of 9 dB in the case of eightmultiplexing. In this study, we demonstrate optical loss reduction for multiplexing using a nonauxiliary WSS approach without an auxiliary optical circuit. The experimental results show that the optical loss for the Nyquist eight-pulse train is successfully reduced to 2.8 dB.

Flexible and lossless baud-rate switching for 4-time slots Nyquist OTDM signals using wavelength selective switch

“…Our WSS-only approach is originally developed to aim at the reduction of the optical loss in repetition rate tuning process [28]. In the flexible baud rate switching, the optical loss caused by increasing RS from RL to B/Ns can be effectively reduced.…”

“…This approach can generate an optical Nyquist pulse train using a WSS only and does not require any devices for OTDM. Using the WSS-only approach, we have demonstrated the generation of optical Nyquist pulse trains in the nearinfrared band without any established OTDM device [27] as well as the generation of power-efficient optical Nyquist trains [28,29]. Recently, we have demonstrated the flexible baud rate switching for the Nyquist OTDM signals [30]; however, the system configuration used in this work [30] is not suitable for the data modulation of each time slot because we used a single output port in WSS.…”