Doctorate for R and D boss

University of Warwick postgraduate, Roberto Ramirez-Iniguez, has been presented with a PhD in engineering in the field of optical wireless communications.

University of Warwick postgraduate, Roberto Ramirez-Iniguez, has been presented with a PhD in engineering in the field of optical wireless communications.

This follows five years of study and groundbreaking work on the development of a revolutionary optical device with Coventry based Optical Antenna Solutions (OAS) as its Research and Development Manager.

The main objectives of his PhD were to investigate the problems of providing optical communication using IR radiation, to find ways to overcome the drawbacks experienced in this kind of technology and to find ways to increase the transmission speed, safety, sensitivity and distance in optical wireless links.

Most of Ramirez-Iniguez's PhD work was related to the design, fabrication and use of optical concentrators for wireless IR communications.

He was aware that by designing receivers with a large effective collection area and narrow optical bandwidth the problems of path loss and background light noise in an optical wireless link could be reduced.

The problem of large area detectors is that their high capacitance leads to an increase of thermal noise and to a reduction of receiver bandwidth, and new ways to increase the receiver collection area had to be found.

Also, it is desirable to use transmitters with a narrow optical spectrum to allow the receiver to employ a narrowband optical filter to reject ambient light radiation and other sources of noise, and this had to be taken into account too.

A solution to these problems is to use an optical concentrator to improve the collection efficiency of the receiver by transforming light rays incident over a large area into a set of rays that emerge from a smaller area.

This implies that smaller photodetectors can be used, which reduces the capacitance, the cost, and improves receiver sensitivity.

The use of omnidirectional and directed concentrators in conjunction with different sorts of optical filters effectively screens out unwanted ambient radiation and increases the effective area of the receiver.

Ramirez-Iniguez previously completed a master's degree in communications and real-time electronic systems at Bradford University and started his PhD work there under the supervision of Prof Roger J Green.

When Prof Green moved to Warwick University to create the Communications and Signal Processing (CSP) Research Group Ramirez-Iniguez followed him as he believes it to be one of the best universities in the UK and it is highly ranked in research.

His involvement with OAS commenced towards the end of Ramirez-Iniguez's PhD when the main focus of his attention was his PhD thesis.

At this point OAS' optical antenna, designed to provide infra-red technology with a new generation of high-collection/low-noise receiver structures, was moving from academic research into a commercial reality.

At the end of his PhD Ramirez-Iniguez took the opportunity to join OAS as its Research and Development Manager and committed to develop the optical antenna further.

Commenting on the positive effect of the OAS relationship Ramirez-Iniguez explained: "When carrying out academic research you do not always have to take into account real issues like economic budget or feasibility of materials.

When producing theoretical models you may assume ideal variables, but this is something you cannot do in industry.

By working for OAS while finishing my PhD I had become involved with other parts of the project and had to take into account a number of real world restrictions".

He continued: "I was able to include in my PhD data from real measurements that I would not have had otherwise and I gained valuable experience taking a theoretical design into a real product".

Alex Clarke, Marketing Manager for OAS congratulated Ramirez-Iniguez: "Roberto was instrumental in creating the success that came of taking our unique optical antenna to market.

As manager of our R and D team he has great plans to further develop the antenna into a semi-conductor component as a result of the worldwide success and industry-wide interest we have received since the launch in November 2002".

He added: "On behalf of Optical Antenna Solutions, I would like to thank Roberto for his excellent work and congratulate him on the receipt of his PhD".

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