OCRG Research Areas

The OCRG research interests are in the following areas;
 

  • Optical Fibre Communication System (design and implementation)
  • Photonic All Optical Switching
  • All Optical Time Division Multiplexing
  • Photonic Network Optimisation
  • Optical Buffering and Routing
  • Optical Cross Connects
  • Soliton Based Optical Communications
  • Mathematical and Computer Modelling of Communications systems 
  • Optical Wireless Communications Systems
  • Communications Network Analysis: traffic , security etc.
  • Fuzzy Logic Application in Micro Strip Lines
  • Intelligent Based Communication Networks
  • Digital Modulation Schemes
  • Optical Fibre Brag Grating,  
  • Optical Sensor


Current Research Activities

 

Text Box: Agilent Sponsored Photonic Research Lab

 

  • Optical Wireless Network

There is an increasing demand for access to ultra broadband wireless access network, Wireless multimedia applications and wireless video, by the end users such as hospital, teaching environments, shopping, etc. Currently there are two main technologies, radio and optical, capable of offering these services. Radio has the advantage of being available ubiquitously both outdoor and indoor and it also offers mobility, but will be challenged to provide the required high bandwidth. On the other hand, the optical wireless option could provide a cost effective, flexible, secure, ultra-high speed solution to the emerging challenges facing the system and service providers. The last few years has seen a considerable interest in both outdoor and indoor optical wireless communications from materials, devices to system and network. Our research is mainly based on: - Modulation techniques - System modelling (analytically and software) - System design and implementation - Hybrid multiplexing techniques - Application of AI and wavelet transform to combat multipath dispersion - Coding. 

 

  1. Free Space Optics

 

       C:\Documents and Settings\p922269\My Documents\FSO Equipment\FSOlinkpix\DSC00003.JPGC:\Documents and Settings\p922269\My Documents\FSO Equipment\FSOlinkpix\DSC00004.JPGC:\Documents and Settings\p922269\My Documents\FSO Equipment\FSOlinkpix\DSC00005.JPG

 Pictures showing a 4-beam-4-reciever free space optical communication system connecting Northumbria and Newcastle Universities at a data rate of 155 Mbps.

 

2.    Free Space Optical Simulation Chamber

 

Chamber with Smoke.

 

3.    Neural Network and Wavelets for Signal Denoising, Adaptive Equalization and Error Control Decoding for Indoor Optical Wireless System

 

A new receiver architecture based on Wavelet and Neural Network is designed and implemented using a DSP board, see below.

 

*      Optical Wireless Data Link  

      Infrared serial ports are now common on laptops, palmtops, PDAs, digital cameras and even mobile phones, allowing data transfer at speeds of up to 4Mbits/sec. However, such systems require a line-of-sight in order to operate, and have a range of just 1 metre for bit error rates of better than 1 in 10^9. By using diffuse propagation (which relies on reflections from ceilings, walls and reflecting objects within a room to provide coverage), It is possible to design optical wireless systems which do not require a line-of-sight between the transmitter and receiver.

 

             

 

      Unlike optical fibre systems, diffuse optical wireless systems are susceptible to ambient light (both natural and artificial) and require relatively high optical power levels in order to operate. However, optical wireless transceivers are subject to eye safety regulations, which limit the average optical power level that can be emitted. Furthermore, power consumption must be kept to a minimum in battery-powered portable devices. Thus, a power efficient modulation scheme is desirable in order to maximise the peak to average power level, and for this reason, pulse position modulation (PPM) has been used extensively. Digital pulse interval modulation (DPIM) is a technique which displays a higher transmission capacity compared to PPM, and requires no symbol synchronisation in the receiver.

DPIM modulation and demodulation circuitry can be implemented on a FPGA development board (pictured above), allowing system parameters such as the clock frequency, number of bits per symbol and even the actual modulation scheme to be changed, simply by reconfiguring the device.


Current PhD projects

Papers          Presentation Slides

 
  • High Speed Optical Network

With Internet traffic doubling every 3 months, it is becoming more evident that the only technology capable of providing the necessary wide bandwidth for future local and wide-area networks would be light wave technology. It would be very difficult for optoelectronic switches to cope with transmission routing in today's optical networks running at tens of Gigahertz. Therefore, future high-speed packet switching will be done predominantly in the optical domain. We are interested in simulation and modelling of:

                   

                                             SMZ based all-optical switch

1- All optical Time division multiplexing (OTDM) network as used in Local Area Networks and Metropolitan Area Networks. 
2- Mutlihop architecture which offer scalability; an important consideration for optical networks based optical routing.
3- All optical Buffering.


Current and Past PhD projects


Papers          Presentation Slides

 
  • Optical Sensors:

Here we are interested in optical gas and environmental sensors based on a Long Period Fibre Grating, where the optical properties of the sensor are very sensitive to the refractive index of the medium surrounding the cladding. This scheme allows the fibre to maintain it's original strength, and it also offers simplicity in design and implementation by avoiding etching the cladding. Modelling and implementation are carried out. 
Current projects are:

Papers          Presentation Slides