Guided-Wave Photonics

Bishnu P. Pal

Mahindra University, India

The field of guided-wave photonics (GWP) examines the phenomena associated with the confinement of light in composite structures comprising two dielectrics having distinct refractive indices. GWP has been the driving force behind landmark developments such as high-speed, long-range optical fiber communication (OFC) systems and photonic integrated circuits (PICs) for signal processing at optical frequencies. Optical fibers and photonic components have, unquestionably, revolutionized how we communicate and access information today.

My first encounter with this fascinating area was as a Royal Norwegian CSIR (NTNF) post-doctoral associate (1975–77) with the Electro-optics Group (ELAB) headed by Professor Kjell Bløtekjaer at the Norwegian University of Science and Technology, Trondheim (then called NTH). It was a pleasant coincidence that both Kjell and I had both been involved in research on electron transport in semiconductors and had decided to move on to this emerging S&T field around the same time. Since then, I have been indeed fortunate to have witnessed the tremendous growth of GWP and to have been a part of that growth.

There is a lesson here-sometimes, we are too committed to our field of study during, say, graduate school and become wary of stepping out of our comfort zones. However, from personal experience, I can attest to the fact that the rigor of graduate school goes a long way towards developing the ability to comprehend new concepts and empowers young researchers to switch to new fields and make remarkable strides therein. The bandwidth of knowledge and dissemination then can grow much broader for an educator, which eventually yields rich dividends. I never regretted this switch over! One of my primary tasks while at NTH was to characterize the index profiles of newly fabricated, high-silica, low-loss fibers.

I returned to India in the Fall of 1977 to join the Indian Institute of Technology (IIT) Delhi’s Fiber Optics Group, which was led by a former SPIE Educator Award recipient, Professor Ajoy Ghatak, who was keen on starting a new laboratory for fiber optics. This was a great opportunity for building a new research laboratory from scratch. Our first efforts were to characterize telecom-grade optical fibers and, in the fall of 1980, succeeded in launching an IDP (Interdisciplinary) MTech teaching program in optoelectronics and optical communication jointly with EE faculty, who also developed the dedicated laboratory for communication aspects in their department.

The program ran successfully, with equal credits provided by each participating team, and became an excellent model for programs run jointly between multiple academic departments. Within a few years from its inception, it became one of the most sought-after MTech programs at IIT Delhi. We were possibly one of the first programs in the world to start a full-fledged masters’ level inter-disciplinary program.

From 1982–83, as an Alexander von Humboldt Fellow at the Fraunhofer-Institut für Physikalische Messtechnik (IPM) in Freiburg, Germany, I co-authored with my host, Prof. Ralph Kersten, a paper that proposed a collection of cutting-edge (at that time) topics along with experiments in the area of optical waveguides as a pedagogy. The paper was published in IEEE Transaction in Education E-28, 46 (1985). At the time, there was a general shortage of technical prowess among those trained in photonics (in India), and our collective goal was to empower graduating students to become successful professionals and to join a global talent pool, serving in both industry as well as in academia and national research laboratories.

Today, our alumni hold key positions in multinational organizations such as Facebook, Google, Infinera, Cisco, Bell Labs/Lucent Technology, NASA, Sterlite Optical Technologies India, Bhabha Atomic Research Centre (BARC), and the Indian Space Research Organization (ISRO), to name a few. The Fiber Optics Lab at IIT Delhi also significantly expanded over the years under the mentorships of other colleagues.

Since then, GWP has made rapid strides during the last 50 years, so much so that data/signal transmission at 200–400 Gbps is now a reality, enabling overall transmission of Tbps per fiber cable. The emergence of critical scientific advances and exciting real-world applications provide boundless opportunities for educators and students in this field. I wish the community the very best in the years to come.