Photonics Briefings Series


Second Asia-Pacific Polymer Fibre Optics Workshop
Hong Kong, China • 3-4 January 2003.
A report by Dr. Demetri Kalymnios
London Metropolitan University, UK

As the name implies this is a follow up workshop and the first one was held two years ago, in Sydney, at the University of New South Wales. This time the workshop was held at the Sheraton Hotel in Kowloon, a prime location for looking over the brightly illuminated unique skyline of Hong Kong Island, with its countless skyscrapers. Many of them were brightly and colourfully illuminated from top to bottom as part of the seasonal celebrations. One could not avoid wondering if POF had been used for some of these illuminations especially those with the more intricate artistic effects.

The attendance was announced as close to 100, in fact double the attendance of the first such workshop. The total number of contributions was about 33 from eight countries as follows: Japan (3), China (21), Germany (2), UK (1), Australia (5), Malaysia (2), Korea (1) and India (1). This meeting was greatly honoured by the attendance of two eminent father figures of fibre optics, Prof. Charles Kao, CBE, and Prof. Alex Gambling. It was pleasing to us all and probably more so to Prof. Y. Koike, of Keio University, who was also present and also a father figure of POF, to hear the above veterans talk about a great future for photonics, fibre technology in general and in particular polymers and POF.

The workshop was appropriately opened by C. Kao, CBE. It was fascinating listening to his vision of a future, involving ‘The powerful new technologies’ of Information Technology, Biotechnology, Nanotechnology and the impact that polymers have had and will continue to have in our lives. From plastic wrappers and nylon stockings, as household items, to new devices such as polymer light emitting diodes.

A number of the papers were invited contributions and these effectively reviewed the state of the art in POF. The Giga-Island concept realised with high-speed GI-POF and which was demonstrated for the first time at the last POF international conference last September in Tokyo, was reviewed by Prof. Koike and co-workers from Keio University. In the Giga-Island concept, fundamental role plays the graded index POF such as the Asahi Glass Lucina, a perfluorinated (PF) GI-POF which has an attenuation of less than 40 dB/km over a wide spectral range (0.5mm-1.3 mm). Applications for PF-GI-POF are in the Gbps region with a link length appropriate for the ’last mile’. Typical applications include the office LAN, home networks in multi-story buildings and apartments, networks in hospitals, fibre channel connections in Storage Area Networks (SAN) and similar. Standards that can be met with PF-GI-POF and at various lengths, include Fast and Gigabit Ethernet, Fiber Channel (125Mbps – 2Gbps), ATM (155 Mbps – 622 Mbps) and IEEE 1394 (S400).

In the light of recent developments in LED sources such as RCLEDs and especially in the green using GaN, the performance of the standard (1mm) high NA, POF has been re-appraised. In one of the contributions (present author) it was shown how the green LED can increase the link length and how mode scrambling at the receiver end can almost double the link bandwidth. It has been shown that the ‘scrambled’ improved performance of high NA POF approaches that of low NA POF. Currently, high NA-POF is increasingly used in the automotive industry and in industrial process control. Testing in a standardised way for POF reliability therefore, is becoming a crucial aspect of these applications. Standard POF testing techniques as currently used were reviewed by one of the contributions from Germany (BAM).

A few of the contributions related to studies of the properties of polymer materials such as ways of decreasing the losses in the PMMA based fibres, studying the characteristics of rare-earth or dye doped fibres, including their use as fibre amplifiers. Considerable research effort seems to be directed towards thin polymeric devices such as Fiber Bragg Gratings (FBG) for use either as strain sensors or temperature sensors and as filters in wave-guide structures. The thermo-optic properties of polymeric wave-guides are also attracting considerable interest for digital optical switching or for controlling the birefringence in polymeric optical wave-guides. The status and trends in polymeric wave-guide devices was reviewed by the second contribution from Germany (Heinrich-Hertz Institute). It was of great interest that one whole session (3 contributions) were devoted exclusively to micro-structured POF (MPOF). These fibres are also known as ‘holey fibres’ or ‘photonic crystals’ and are a novel type of fibre whose core is a solid central region of a few tens of microns diameter and the cladding is provided by a series of longitudinal holes (air tubes) that run parallel to the core. This fibre (in glass) was first discovered at Bath University in 1996. It is a fibre with rather unusual transmission characteristics and it is generally believed that it can have some very exciting applications. For example, a large core single mode fibre for a wide range of wavelengths, a fibre with prescribed non-linear properties depending on its structure and others. MPOF is considered to offer significant advantages over glass holey fibres, mainly because of the flexibility of polymers and the ease of handling. It is interesting to note that the MPOF presentations came from Australia and that there is a recently founded company (Cactus Fiber) advertising products of MPOF. One of the contributions from China referred to the various POF manufacturing capabilities within the country. It was reported that all types of POF are being considered for commercial exploitation. Currently, the most successful POF product in China is polystyrene (PS) POF mainly used for decorative purposes (mostly christmas trees). In the year of 2001 the size of the market was estimated to be 3000 tons of POF or an equivalent POF length of 18.000.000km!

It is also interesting to mention that one of the opening speeches was about the Hong Kong Science and Technology Parks Corporation (HKSTP) that was inaugurated in May 2001. It is "a government statutory body established to bring the world-class technology and the most highly skilled workforce together in a purpose built environment so as to create co-operative, clustering and synergy effects. The Parks are designed to accommodate companies of all sizes and stages of development and to promote interaction and innovation on both local and global basis".

Photographs of these parks were shown with many buildings reported completed and fully equipped for their purpose. This is a very impressive initiative and the expectation seemed to be that all Hong Kong Universities could play a leading role in the success of all new companies that will be accommodated in the Parks. These companies will be heavily subsidised during their initial stages but are expected to establish themselves within a 3-year period and move out of the parks.

All in all, this workshop was most successful and it was a most enjoyable experience. There was plenty of opportunity for the participants to interact and the hospitality extended by the organisers was most generous. This workshop was organised by Prof. Pak Chu, Director of the Opto-electronics Research Centre, City University of Hong Kong. The 3rd Asia-Pacific POF workshop is already scheduled for early in 2005 and the location will be decided at a later date. The Workshop proceedings were also produced on CD and this may be obtainable from Information Gatekeepers Inc.