Yong-Kee Yeo

An optical switch with load balancing capability can play important roles in reducing power consumption, enhancing scalability, and optimizing bandwidth utilization for data centers. This letter proposes a novel scheme to build up such an optical switch fabric using polarization division multiplexing. In the switch, the functions of load balancing and switching are simultaneously performed by two orthogonal polarizations, respectively. This feature allows the switch to double its throughput without an increase in its port count or reconfiguration speed. A 1 × 32 optical load-balanced switch with this scheme is successfully demonstrated. Experimental results show that the switch exhibits good polarization independence and the average power penalty is 1.3 dB.

This paper presents a new passive optical network (PON) architecture that applies an optical multicast capable switch (OMS) to direct wavelengths to a set of PON branches and enables them to share the transceivers in the central office (CO) on demand. The OMS is composed of fiber splitters and switching gates, and by controlling the on-off gates the wavelengths at the inputs can reach any outputs of the OMS. Through the OMS configuration, logical PONs are dynamically formed according to changing traffic patterns, and traffic is further scheduled in the time domain within each logical PON. The proposed network achieves network resource sharing without requiring tunable transceivers or wavelength filters, and without changing deployed network devices in the field or at the user end. Analysis and experimental study results show the efficiency of resource sharing and demonstrate the concept of resource sharing among PON branches.

We propose a method to precisely detect the faulty branch of time-division-multiplexing-passive optical networks (TDM-PONs) by encoding the probe signal with optical orthogonal codes. The proposed technique projects each probe signal response onto an orthogonal space, wherein an event corresponding to each branch of the TDM-PON is uniquely mapped onto an orthogonal basis and thereby able to isolate the origin of the event to a particular branch. A proof-of-concept experiment is carried out on a 1 × 16 TDM-PON with 20 km feeder fiber and the results confirm that, with the proposed design the system can support up to 120 m branch fiber length with 3 m spatial resolution.

In this paper, we introduce our Home2015 project - wavelength-agile optical access networking system. We propose a multi-wavelength access network to offer higher system capacities for next-generation optical access. Our proposed concept of virtual PON (VPON) is introduced to realize dynamic ONU re-grouping functionality. Optical network units (ONUs) in the PON system can dynamically form different TDM-PON by using a different downlink and uplink wavelength channel. Novel photonic silicon chip integration techniques are introduced to reduce size and cost of the ONUs. We also introduce our works on live 3D hologram video transmission platform design and live 3D hologram video transmission via the 10-Gb/s wavelength-agile optical access network. Our demostration shows that our system has good transmission performances.

In this paper, we propose and demonstrate the practical all-optical wavelength multicasting scheme based on the four-wave mixing (FWM) effect in both a highly nonlinear fiber (HNLF) and a semiconductor optical amplifier (SOA). Then we carry out comprehensive comparisons of the performance differences between using the HNLF and SOA for this proposed multicasting scheme. Seven multicast channels are experimentally demonstrated by using three co-polarized probes and a modulated signal. The merit of the proposed scheme is that the polarization sensitivity is significantly reduced from more than 20 dB to approximately 5 dB using the HNFL and 2.5 dB using the SOA. The low polarization sensitivity leads to a difference of less than 1 dB in the power penalty of the multicast channels at bit error rate . In addition, we compare the multicasting performance of the OOK and differential phase-shift keying (DPSK) signals using the proposed scheme and found that the power penalties of the DPSK multicast channels in the HNLF and the SOA are less than 1.25 and 1.1 dB respectively, and the power penalties of the OOK multicast channels are less than 1.5 dB and 3.1 dB in the HNLF and the SOA, respectively.

We present a new, endless polarization control method based on two rotatable wave plates with variable birefringence. We propose two boundary conditions for the parameters of the wave plates so that this method will not have the pole problem. The pole problem is one of the main weaknesses in reset-free polarization controllers. We experimentally demonstrate the control principle of this method and verify its feasibility by using a simple feedback mechanism.