SPIRIT: Self-Pulsating lasers Incorporating Radio Interface Technology

S.  D.  Walker and D.  Mirshekar, Department of Electronic Systems Engineering, University of Essex, Wivenhoe Park, Colchester, Essex, C04 3SQ

 

            Dr. Stuart Walker joined the University of Essex in February 1988 as a Senior Lecturer in Optical Communications. Previously he was at BT Laboratories, where he was latterly head of the submarine systems development group. During his time at BT, he was involved in many pioneering developments. These included bringing forward the unrepeatered optical link concept and participation in the first multi-gigabit UK installed fibre field trials. He was mainly responsible for the design of all the Opto-electronic modules including a complete 2.4 Gb/s regenerator.

 

            Since joining the University of Essex, he has participated in many University/Industrial partnerships. These include an extended period as a consultant to Hewlett-Packard (HP) Laboratories, Bristol and Agilent Technologies, Ipswich. He has also served as a Visiting Scientist to HP, Bristol on two occasions. One aspect of the work with HP was concerned with the optimisation of subcarrier network performance. It was shown, for the first time, how the best laser modulation index simply depended on the device non-linearity and required network signal-to-noise ratio. This result [1] was widely cited. A novel means for subcarrier optical network distortion analysis was also discovered and granted a US patent. He has successfully completed international contracts for IBM T.J. Watson Research Centre and served there as Visiting European Scientist. One outcome from this collaboration was the demonstration of the first subcarrier-multiplexed optical network based on self- pulsating lasers. He has been appointed a visiting BT fellow on two occasions. In the BT context, various novel laser transmitter control systems were designed. A European patent was generated by this work.

 

            In partnership with colleagues at the University of Essex, he has been co-applicant and principal investigator on a number of successful EPSRC submissions. These include GR/K49454, "Development of a polarisation-sensitive optical time domain reflectometer (P-OTDR)". Dr. Walker's contribution has been to design a high-performance, four channel Stokes receiver. This allowed convenient, single-ended laboratory measurements to be carried out. Prior to this, he was involved with GR/J45114, "Polarisation dispersion limitations on the performance of long-haul, multi-gigabit fibre links". The main contribution here was to design a unique, DSP- optimised receiver with the lowest noise available. He was involved with GR/L62832, "Polarised soliton transmission and linear differential polarisation-shift keying transmission". In this project, the design of a complete digital modem is being undertaken, thus enabling the planned experimental work in polarisation-shift signaling.

 

 Subsequently, he has joined a successful proposal with Bristol University, GR/L89105 entitled "Low cost sub-carrier multiplexed optical networks as Essex principal investigator. This project, which is strongly supported by HP Laboratories and News Digital Systems Ltd., has produced a number of new results in the area of multi-gigabit capacity subcarrier systems. Dr. Walker’s main concern is with the design of complete subcarrier clock extraction and phase-lock sub-systems. Recently, he was awarded further funds to pursue a project entitled "Arrayed-waveguide grating Cascade Optical Research Network (ACORN)", GR/N11070 in collaboration with Dr.'s Mears and Holburn at Cambridge University. This work is in the area of arrayed-waveguide grating based networks for future high-capacity access networks. Recently he was awarded funding for the "OAKLEAF' project, GR/R32819 which is also in collaboration with Cambridge.

 

            The optical systems and networks laboratories at the University of Essex are involved in a number of EPSRC, European and Industrial projects. Support has been received from a wide variety of sources such as Alcatel, BT, FTEL, Agilent Technologies, HP laboratories, Bristol, and Nortel.

 

  Selected References:  

 

[1]S.D. Walker, M. Li, A.C. Boucouvalas, D.G. Cunningham, A.N. Coles, "Design techniques for subcarrier multiplexed broadcast optical networks", IEEE Journal on Selected Areas in Communications, vol.8, no.7, September 1990, pp. 1276-1284.

 

[2] S.D.Walker, R.J.S.Bates, "Optical networking and signal-processing applications of 790nm self-pulsating laser-diodes", IEE Proc. J. Vol. 139, no.4 August 1992, pp.263-271.

 

 

Current staff and student members who work with Prof. Walker are:

Dr. Jason Lepley (Research Officer)                                    email:  jjlepley@essex.ac.uk

Dr. Sandra Dudley-McEvoy (Research officer)                email: sdudle@essex.ac.uk

Ioannis Tsalamanis                                                                   email: itsala@essex.ac.uk

Chak H. Hum                                                                             email: chhum@essex.ac.uk

Terry Quinlan  (Research Technician)                                email: quinlan@essex.ac.uk

Makhfudzah Mokhtar                                                             email: mmokht@essex.ac.uk

Manoj Thakur                                                                            email: mpthak @essex.ac.u

 

website maintained by Sandra Dudley-McEvoy. Page last updated 22/03/ 05