Yong-Kee Yeo

Enabling Technologies for Next-Generation Optical Packet-Switching Networks

The optical packet-switching network is considered to be one of the most promising solutions for end-to-end delivery of high-bitrate data, video, and voice signals across optical networks of the future. Optical label switching (OLS) technology incurs simpler extraction and processing of the labels so that the optical packets can be routed with low latency to the destinations. We have developed several key enabling technologies for integrated optical networks, including optical label generation, label swapping, optical buffering, clock recovery, and wavelength conversion. We have designed and experimentally demonstrated these enabling techniques that can provide efficient broadband services in future optical networks

A dynamically reconfigurable folded-path time delay buffer for optical packet switching

A novel all-optical buffer based on adjustable time delay line is proposed and experimentally demonstrated. This physically compact buffer can be used in optical packet routers and is dynamically reconfigurable within nanoseconds. By using a flexible folded-path architecture design, packets are controlled to exit the buffer immediately or after a variable delay time. Furthermore, this functionality is achieved without sacrificing the scalability and compactness of the design.

Optical carrier suppression and separation label-switching techniques

We report our recent research results in the area of optical label switching (OLS) for next-generation optical packet-switched networks. These include optical label generation, label swapping, optical time-delay buffering, clock recovery (CR), and wavelength conversion for optical packets.

DWDM reconfigurable optical delay buffer for optical packet switched networks

We proposed and demonstrated a novel scheme to realize wavelength-selective reconfigurable optical delay buffers using optical fiber delay in a folded-path architecture. The experimental results show that multiple wavelength 10-Gb/s dense wavelength-division-multiplexed packets with 50-GHz channel spacing can individually be delayed a variable amount of time simultaneously with a power penalty less than 1 dB using the proposed reconfigurable buffer architecture

Bi-directional transmission of 8x10Gb/s DPSK signals over 80km of SMF-28 Fiber using in-line semiconductor optical amplifier.

We report the bi-directional transmission of 8x10Gb/s signals using an in-line SOA over 80km SMF-28 with matching DCF for the first time. Our results suggest very promising applications for bi-directional transmission in metro and access networks with simple configuration and low cost.

Design and Implementation of A Low Cost, Integrated Platform for Delivering Super-Broadband Dual Services Simultaneously

We demonstrated an optical-wireless testbed delivering wired and wireless services simultaneously in an integrated ROF and WDM-PON access network. It was successfully transmitted 270Mbit/s uncompressed SDTV and 2.5Gbit/s data over 25km fiber and 10.2m wireless link.

A broadcast and multicast-enabled switch architecture utilizing a gateless channel selection scheme

We experimentally demonstrate a new switch architecture that supports simultaneous multicasting/broadcasting for all input ports. Unlike existing architectures, it does not require any optical ON-OFF gates, and is transparent to signal modulation format and bit-rate.

A novel scheme for generating optical dark return-to-zero pulses and its application in a label switching optical network

We experimentally demonstrate a novel and simple method to generate a dark return-to-zero (RZ) pulse with tunable pulsewidth and extinction ratio by using a dual-arm LiNbO /sub 3/ intensity modulator. Our experimental results show that this dark RZ pulse signal can be used in a 10-Gb/s optical packet switching system as an optical label. In addition, we demonstrate that this dark RZ label can be easily erased using the gain saturation effect in a semiconductor optical amplifier.

Performance of DPSK and NRZ-OOK signals in a novel folded-path optical packet switch buffer

A novel and physically compact optical time delay buffer with nanoseconds reconfigurability is presented. Experiment results showed that the optimization of various design parameters resulted in greater range of delay value and smaller delay time step granularity.

Novel techniques for optical packet generation with high-spectral efficiency and high receiver sensitivity

We report generation and transmission of high-spectral efficiency and high receiver sensitivity optical packet with 25 GHz frequency spacing between 40 Gbit/s payload and 2.5 Gbit/s label by using novel enabling techniques.