A brilliant physicist of international recognition whose original work in the fields of optical communications stimulated what was a paradigm of collaboration between academe and industry. Prof Ahmad work contributed greatly to the understanding of Polarisation Mode Dispersion (PMD). This work led to the invention of the first real-time optical polarimeter; which was granted a US patent in 1992. Ahmad Shamin Siddiqui was born in Patna, grew up in Karachi and after doing degree came to Britain where his career expanded. He died in Colchester.