An International Peer Reviewed Research Journal

Title Vol 30 No 5, 2021


SSN : 0971 - 3093

Vol 30, No 5, May, 2021


Journal of Physics


Volume 30                                                               No 5                                                              May 2021


A Special Issue Dedicated
Prof Anurag Sharma

Guest Edited By : S N Tripathi and V K Rastogi

Anita Publications
FF-43, 1st Floor, Mangal Bazar, Laxmi Nagar, Delhi-110 092, India


About Professor Anurag Sharma

Born on May 7, 1955 at Bareilly (UP), Prof. Anurag Sharma did his post graduate education at IIT Delhi obtaining Ph.D. in 1979. He joined, in 1980, the Physics Department, IIT Delhi, as a faculty member. He is currently a J. C. Bose Fellow and the ‘Class of 66’ Chair Professor.
    Professor Sharma has made several significant contributions in the area of modelling and analysis of optical waveguides and imaging devices and components developing several new techniques for propagation of optical rays and waves. He is known for his research in guided wave optics and is credited with the development of analytical and numerical methods for dielectric optical wave guides, single-mode fibers, Graded-Index (GRIN) devices and optical imaging system. He developed a protocol for tracing GRIN media for use in imaging systems which improved the computational efficiency of ray tracing by at least two orders of magnitude.


The method was immediately adopted by the international community and it continues to be part of all commercial optical design softwares even today. He has also developed an entirely new concept in wide-angle beam propagation has become important in view of continuous effort in miniaturization of devices. He has also developed the use of the variational method for single mode waveguides and optical fibers. Over the four decades he has analyzed various waveguides which came up due to developments in technology. He has published over 110 papers in journals and over 200 papers in conference. He has coauthored a book and has edited another. He was involved in several international collaborations with UK, Japan, Norway, Germany and France.
    For his outstanding contributions, he has been honoured with many awards including the Shanti Swarup Bhatnagar Prize for Engineering Sciences (1998), Young Scientist Medal (1986) and the A.K. Bose Prize (1991) by the INSA, M.N. Saha Award (1999) of the UGC, Homi Bhabha Fellowship (1990-92), M.N. Saha Lecture Award (2017) by the NASI and the Om Prakash Bhasin Award (2018). He is a Fellow of the INSA (2004), the NASI (1998), the IASc (2002), the INAE (2009), the IETE (1991) and the OSA-the Optical Society (USA, 2004). He is a Distinguished Fellow of the Optical Society of India. He has also been an Alexander von Humboldt Fellow (1982-83) at Karlsruhe University (Germany) and an Associate (1988-1999) and a Senior Associate (2001-2006) of the Abdus Salam International Centre for Theoretical Physics, Trieste (Italy).
    Professor Sharma has contributed to the cause of optics and photonics by organizing several workshops, seminars and conferences. Just to mention a few: he was the Secretary of Photonics-1998, co-chair of Photonics-2008 and Chair of Photonics-2018 held at IIT Delhi. He also organized the annual symposium of the OSI in 2011. Recently, he has initiated since 2017 annual workshops on Optics and Photonics: Theory and Computational Techniques (OPTCT).
    He has served IIT Delhi in various capacities. He was the Dean of Students (2006-2009), the Chairman, Golden Jubilee Committee (2009-2011), the Dean Academics (2012-2016), the Head, Physics Department (2016-2019). He also acted as the Dean of Student for IIT Ropar (2008-2009) and the Professor I/C (2016-17) and the Dean (2017-2019) for Academics for IIT Jammu. He was a member of the BoG (2014 and 2016) and the Chief Vigilance Officer of the Institute (2017-2020).
    Professor Sharma has also been involved in various academies, societies and national bodies. He was a Vice-President of the INSA (2017-2019), Member Governing Council, INAE (2016-2018) and has been serving NASI, DST, CSIR and DRDO through membership of various committees. He was the Vice-President (2008-11) and is currently, the President (2018-21) of the Optical Society of India.

Appreciation by Kehar Singh

It gives me immense pleasure to write about Professor Anurag Sharma whom I have known for about 46 years, first as a student and later as a valued colleague at IIT Delhi.
    It was in 1974 that as a student of M Sc.(2nd year Physics) program, he opted to carry out his project work on holography under my supervision. At that time, I had only a small laboratory in which there was a home-made table, a low power He-Ne laser, and some optical-, and mechanical components to record small holograms. A cast iron plate was floated on four inflated scooter tubes kept on a sturdy wooden table. Four legs of the table were placed in four baskets filled with sand. Such a table dampened sufficiently the vibrations even though the table was located on the third floor of the main building having seven floors. Such an arrangement proved to be quite satisfactory for student experiments for recording on-axis and small angle (1-2 degrees) off-axis holograms. For research work, we had to import a commercial table much later. I was not sure as to why Anurag opted to work on holography for his project work. Perhaps, during his course work, he developed a special interest in optics, as also the fact that Denis Gabor won the Nobel Prize in 1971 for his work on holography, which generated unprecedented interest in ‘Holography’across  the globe, making it a much sought- after subject. It is an interesting coincidence, that the laboratory room in which he performed experiments for his dissertation, was used after a lapse of nearly four decades to house newly created infrastructure for Ultrafast Optics. I along with Prof A K Ghatak were invited by Prof. Sharma to inaugurate the laboratory. Such is the respect he gives to his teachers.
    Anurag kept his interest in optics alive, and joined the M.Tech.(Applied Optics) program in 1974, during which I taught him several theory courses and supervised the ‘Optics laboratory’ work for two semesters. During this period, his interest in optics deepened further and he completed the program with flying colours. His unsatiable hunger for knowledge intensified further and he decided to join for the doctoral program in optical waveguides with Professor A.K.Ghatak. During his doctoral work, he did some remarkable research. It would be an exercise in futility to write about his academic and professional attainments and his career trajectory, which are outstanding and also given in the accompanying pages in this issue. Instead, I propose to devote some space to his management and administrative acumen, and personal traits to which I have been a witness from close quarters during my long association with him as a colleague. It is impossible to give a detailed account of my impressions of him in the textual space that a write-up of this nature can accommodate. Therefore, only a few glimpses are listed below:
    Whether it was my responsibility as a coordinator of the M.Tech.(Applied Optics) program for several years or as the Chairman of the Departmental Research Committee (DRC) or as Head of department, or as Dean Postgraduate Programs and Research (BPGS), Prof. Sharma played an important role by giving his sincere, constructive, and valuable suggestions. During my tenure as Dean (BPGS), I received his valuable suggestions and support. This was the period when I had to oversee the designing of new curricula for various M.Tech. programs of the Institute, because the programs which were until then of eighteen months duration, were to be extended to two tears duration as a result of the recommendation by a national review committee.The process entailed discussion at various levels; curriculum framing and approval at the department level, discussion and approval by the BPGS, and finally the approval by the Senate. In this regard, many pertinent and remarkable suggestions were put forward by Prof Sharma at all levels. He was quite firm and had no hesitation in expressing his frank and forthright views if he differed with my point of view at any of the fora. He minced no words if he strongly felt that something was not quite right with the formulation of guidelines and policies which had a major impact on the department and the Institute. At the same time, his positive attitude, and skills to resolve conflicts and suggest acceptable solutions were unmatched. 
    Prof Sharma also edited (with Dr Joby Joseph and Prof V K Rastogi) a book on ‘Perspectives in Modern Optics and Optical Instrumentation’[1] to commemorate my felicitation on the occasion of my 60th birthday. The book contains articles contributed by scientists of repute from India and abroad. An international symposium was also organized on this occasion, followed by dinner at the Director’s lodge. The responsibility of organizing the felicitation function was entrusted to Prof Sharma by the then Director Prof R S Sirohi who was an admirer of his organizational capabilities. Prior to this, he had arranged a conference to celebrate the 60th birthday of Prof. Ghatak,and later edited a book on ‘Guided Wave Optics’ [2] on the occasion of a farewell function in honour of Prof Ghatak at the end of his formal association with IITD. The book is an excellent collection of articles by well- known experts in the area. When a function was held in the faculty house to release the book, I was chosen by him to do the honours.
    The year 2011 was the golden jubilee year of IIT Delhi and year-long celebrations were planned on this occasion. Prof Sharma was entrusted the responsibility of chairing a committee which was to work out a detailed plan of activities and their implementation. Under the able and inspiring guidance of Prof Sharma all the activities were carried out in a very smooth and systematic manner. One of the activities was to honour some faculty members (superannuated and serving) with ‘Golden Jubilee distinguished awards’, after obtaining recommendations by various departments and centres, taking into account the distinguished services rendered by the concerned faculty. An elaborate function was held in the convocation hall to felicitate the awardees and the function turned out to be a memorable occasion for the awardees. The participants were full of praise for the manner in which the ceremony was conducted by Prof Sharma. Another activity that was carried out under his able guidance was the printing of large sized posters depicting the time-line of growth of the Institute by showing certain landmark events. Faculty winning S S Bhatnagar prize were shown with their photographs. An exhibition was also arranged, of books authored/co-authored or edited by the faculty.
    Another project that was planned for the year was to initiate the process of bringing out a book containing the memoirs of the ‘Distinguished golden jubilee awardees’. Prof Sharma wanted me to take up the responsibility editing such a book by inviting articles from the awardees, perhaps due to the reason that I had joined the IITD faculty in 1965 and thus personally knew the senior professors who were my contemporaries. I gladly accepted the invitation because I was sure that he would do a great job of getting the book printed in an elegant style. Unfortunately, due to some unavoidable reasons, publication of the book [3] got delayed and could come out only in 2015.
    It was at the suggestion and persuasive skills of Prof Sharma that I wrote an article [4] entitled ‘Optics and Photonics at IIT Delhi’. It was first printed in the souvenir brought out on the occasion of an International conference on optics and photonics held at IITD during the period Dec.3-5, 2011. It traced the history of development of optics at IITD from 1962 to 2011. and contains the details of faculty associated with the teaching and research programs, courses taught, facilities created for experimental research, doctoral dissertations approved, and honours (various awards including Bhatnagar award and fellowship of various academies) won by the faculty over the years. An extended version of the article was later published in Optics and Photonics News(India), brought out by the Optical Society of America.
    An activity/program called ‘Honour the Mentor’ was also initiated as a part of the golden jubilee celebrations, under which a certain number of students can come together to honour their mentor. These students are normally the ones who were mentored in their doctoral and/or M Tech program. Family, and certain number of friends and relatives are also invited to such a function which was held in the seminar hall. Large size posters were put at conspicuous places such as the main entrance to the foyer outside the venue and near the dais. After a speech by the presider who is normally the Institute Director, the students made short speeches giving their impressions about the mentor who was honoured by presenting him a shawl and a cheque for Rs. Fifty thousand as a token of gratitude. The mentors were required to give presentations about their experiences at the Institute. A booklet with photos of the students and their brief write-ups about the mentor was released on such occasions. A video recording of the complete ceremony, and still photographs were later made available to the mentor and the concerned students. Prof Sharma used to be the ‘Master of Ceremony’ in these functions. The ceremony was followed by an elaborate dinner in the faculty guest house,to which faculty of  over as the concerned department along with their spouses, students, and guests were invited. At such a function in my honour,Prof Sharma while making his remarks about me that Prof Singh always addresses his colleagues in a formal manner by affixing Professor or Dr. before the name. He made a plea not to address him in such a manner and should be addressed only as Anurag because he had been my student. I agreed spontaneously with his suggestion. Since that moment I started addressing him as Anurag.

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Anurag Sharma (on mike) and Kehar Singh

    Anurag has been a moving force behind the series of conference on ‘Photonics’ which have been held at various places in India, once in two years. These conferences attract not only prominent speakers from India, but also quite a few reputed speakers from abroad, and gone a long way in creating awareness of optics and photonics in India.  He also co-edited a collection of selected papers presented at these conferences as SPIE proceedings. I have the honour of being an invited speaker at many such conferences and derived considerable academic benefits by attending these. The most recent one such conference was arranged by Anurag at IITD in Dec 2018 and was a huge hit with the audience. Many foreign speakers whom I know personally still write to me of their pleasant memories of attending and lecturing at the conference. One more recent event that shows his organizational skills was to celebrate the 80th birthday of Prof Ghatak. A seminar was held in the physics department IITD where a special issue of Asian Journal of Physics dedicated to Prof Ghatak, guest edited by Prof. Bishnu Pal was released. This was followed by a gala dinner at which glowing tributes by colleagues, former students, and relatives were paid to Prof Ghatak, making it a memorable occasion.
    After taking over as President of the Optical Society of India (OSI), Anurag has initiated a slew of measures to invigorate the OSI. He has been able to find a solution to the long-pending problem associated with the nomenclature i.e. all members being designated as Fellows. Two new classes of Fellows namely ‘Senior Fellow’ and ‘Distinguished Fellow’ have been introduced to solve the problem and appropriate mechanism has been put in place for their selections. Writing of short monographs by the members is also being encouraged by granting financial aid to the authors for expenditure that may be incurred in the process of such monographs. Appropriate procedures have been put in place for this purpose.

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Anurag Sharma (left) and Kehar Singh (right)

      I wish Anurag good health, happiness, and many more years of productive life in whatever he may undertake. I also wish the same to Enakshi, his life partner who is also an accomplished teacher and researcher in her own right. My best wishes also to the younger members of the family. Finally, I thank Prof V K Rastogi for giving me an opportunity to write this piece in appreciation of Anurag. Prof Rastogi is rendering valuable service in the cause of optics and photonics by bringing out a series of special issues in honour of imminent scientists who have dedicated their lives in pursuit of knowledge in their chosen areas.
1. J Joseph, A Sharma, and V K Rastogi (eds), Perspectives in Modern Optics and Optical Instrumentation   (Anita Publications New Delhi, 2002)
2. A Sharma (ed), Guided wave Optics (Anshan City ? 2006 )
3. Kehar Singh (ed), Those Were the Days, Golden Jubilee Memoirs; Personal Recollections of Former  Faculty Members of IIT Delhi, (Viva Books Pvt. Ltd. New Delhi, 2015).
4. Kehar Singh, Optics and Photonics at IIT Delhi: Past and the Present, in FOP-11;XXXVI OSI Symp. On ‘Frontiers in Optics and Photonics’ Dec 3-5, 2011, IIT Delhi. See also; Optics and Photonics News India (Opt Soc. Am.), Vol 1 Issue 1.

Kehar Singh
Nov. 07, 2020

Appreciation by Bishnu Pal

 Professor Anurag Sharma, FNA has been a very close colleague of mine @ IIT Delhi. In late 1977 when I returned to IITD from abroad after a two-year post-doctoral stint at the Norwegian Institute of Technology at Trondheim, I met him for the first time. He was pursuing Ph D then with Prof Ghatak as his Adviser. He had worked on the then hot area of graded refractive index media and in particular, designs of graded-index lenses. He came out with a new algorithm for such lens design, which is often referred by scientists as “Sharma algorithm” in this field as told to me by Prof Duncan Moore of Institute of Optics @ Rochester once.  There after he moved to more hard-core theory of guided wave optics and components and has had worked extensively on developing variational and other techniques for modeling optical waveguides as well as fibers, some of which like “collocation method” have received extensive citations also. For last several years he has been regularly invited to the Waveguide theory workshop held in Europe before the well-known European Conference on Optical Communication (ECOC) conference series. With some of his graduate students he had worked also on optical designs and has taught this topic to Masters students @ IITD for several years.  Besides his contributions to research, for which he received several prestigious national awards including the coveted SS Bhatnagar award of CSIR and earned fellowships from all the major national academies in India and also the fellowship of OSA The Optical Society (USA), he has also exhibited his prowess in academic administration at IIT Delhi with his out of box solutions to complicated and intricate administrative issues many a times. Together we had actively collaborated in organizing flagship international conferences and workshops in the broad area of Fiber Optics and Photonics several times and I always enjoyed and admired his approach and also his support and advices when I was Chair of the Physics department @ IITD.  As a person he has been very positive and helpful to students and faculty in general.  I am glad to know that AJP is bringing out a special issue in his honor next year and I wish great success of the special issue and him many more productive years of research.
-    Bishnu Pal, Dean Academics,Mahindra University Hyderabad
     Oct 27,2020


Asian Journal of Physics                                                                                                       Vol. 30 No 5, 2021, 00-00

Coupled mode theory and coupled mode photonic devices: A Review

Enakshi Khular Sharma, Jyoti Prasad Nath and Nikhil Dhingra

Department of Electronic Science, University of Delhi South Campus, New Delhi-110 021, India

Dedicated to Prof Anurag Sharma, FNA for his numerous contributions to Optics and Photonics.


A large number of guided wave photonic devices are based on coupling of guided modes between closely spaced waveguides or between guided modes of the same waveguide. Coupled mode analysis has been the most widely used method to study such coupling in which the interaction leads to transfer of power from one waveguide to the other or between modes of the same waveguide due to index perturbations. We present the coupled mode theory for evanescent field coupling between modes of two waveguides placed close to each other in context to the most versatile coupled mode device, a two-waveguide directional coupler. Its variants can be used to design a number of guided wave coupled photonic devices. We will illustrate by presenting a few such devices like switches and modulators, filters, polarizers and multiplexers for silicon photonic integrated circuits. © Anita Publications. All rights reserved.

Keywords: Coupled mode theory, Coupled mode devices, Switches and Mode division multiplexers.


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  2.   Hardy A, W. Streifer W, Coupled Mode Theory for Parallel Waveguides, J Light Technol, 3(1985)1135-1146.

  3.   Syms R R A, Improved coupled-mode theory for codirectionally and contradirectionally coupled waveguide arrays, J Opt Soc Am A, 8(1991)1062-1069.

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  5.   Haus H A, Huang W, Coupled-mode theory, Proc IEEE, 79(1991)1505-1518.

  6.   FIMMWAVE/FIMMPROP, Photon Design Ltd,

  7.   Gupta N, Sharma E K, Modified variational analysis of coupled waveguides, J Opt Soc Am A, 10(1993)1549-1552.

  8.   Kohli N, Srivastava S, Sharma E K, Scalar coupled mode theory and variational analysis for planar SOI waveguide arrays: a detailed comparison, Opt Quant

        Electron, 48(2016)265;

  9.   Kohli N, Srivastava S, Sharma E K, Orthogonal solutions for asymmetric strongly coupled waveguide arrays: an elegant, analytical approach , J Opt Soc Am

        B, 31(2014)2871-2878.

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        International Society for Optics and Photonics., vol. 10537, p. 105370Z, Feb. 2018.

12.   Dhingra N, Song J, Saxena G J, Sharma E K, Rahman B M A, Design of a Compact Low-Loss Phase Shifter Based on Optical Phase Change Material, IEEE

        Photon Technol Lett, 31(2019)1757-1760.

13.   Sital S, Sharma E K, Design Methodology for metal clad polarizer in SOI waveguides, International workshop on Optical Wave and Waveguide Theory and

        Numerical Modelling (OWTNM)-2015, City University London, UK, 16-18 Apr. 2015.

14.   Sital S, Sharma E K, Design Menthology for TE-Pass Polarizer in SOI waveguides, Opt Quant Electron, 48(2016) 369; doi. 10.1007/s11082-016-0636-5.

15.   Nath J P, Dhingra N, Saxena G J, Sharma E K, Compact Mode Division Multiplexed On-Chip Interconnect based on Evanescently Coupled SOI Waveguides,

        The International Conference on Fiber Optics and Photonics, Indian Institute of Technology Delhi, India, 12-15 Dec. 2018.

16.   Nath J P, Dhingra N, Saxena G J, Sharma E K, Compact Mode Division (de)Multiplexer Based on Collaterally Coupled SOI Waveguides, IEEE Photon

        Technol Lett, 32(2020)595-598.

Coupled mode theory and coupled mode photonic devices: A Review.pdf
Enakshi Khular Sharma, Jyoti Prasad Nath and Nikhil Dhingra


Asian Journal of Physics                                                                                                       Vol. 30 No 5, 2021, 00-00

Evaluation of confinement losses in micro-structured optical fibers: an alternative approach

D K Sharma1, H Singh2 and S M Tripathi1,2

1Center for Lasers and Photonics, Indian Institute of Technology Kanpur, Kanpur- 208 016, India

2Department of Physics, Indian Institute of Technology Kanpur, Kanpur- 208 016, India

Dedicated to Prof Anurag Sharma, FNA for his numerous contributions to Optics and Photonics


An alternative method is articulated for the prediction of confinement losses in high-index core micro-structured optical fibers (MOFs) with triangular lattice of rounded air-holes. MOF with finite number of air-holes layers is replaced by a doubly clad fiber (DCF) with a depressed index inner-cladding and then, a simple expression in combination to our optical model for confinement losses in the DCF is resuscitated for evaluation. Simulated results are in-line to those as articulated in the literature. © Anita Publications. All rights reserved.

Keywords: Micro-structured optical fiber, Confinement losses, Normalized frequency


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       Res, 7(2016)1-6.

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       IEEE J Quant Electron, 38(2002)927-933.

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       mode microstructured optical fiber: Impact of core index depression, Opt Express, 21(2013)23250-23260.

  9.  Morshed M, Hassan Md I, Roy T K, Uddin M S, Razzak S M A, Microstructure core photonic crystal fiber for gas sensing applications, Appl Opt,


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11.  Mortensen N A, Folkenberg J R, Nielsen M D, Hansen K P, Modal cut off and the V parameter in photonic crystal fibers, Opt Lett, 28(2003)1879-1881.

12.  Koshiba M, Saitoh K, Applicability of classical optical fiber theories to holey fibers, Opt Lett, 29 (2004)1739-1741.

13.  Sharma D K, Tripathi C M, Implications of theoretical analysis to explore the functional core dimension in one-rod core microstructured optical fibers, Opt

       Quant Electron, 51(2019)318;

14.  Kawakami S, Nishida S, Characteristics of a doubly clad optical fiber with a low-index inner cladding, IEEE J Quant Electron, QE-10(1974)879-887.

15.  Marcuse D, Influence of curvature on the losses of doubly clad fibers, Appl Opt, 21(1982)4208-4213.

16.  Cohen L G, Marcuse D, Mammel W L, Radiating leaky-mode losses in single-mode light guides with depressed-index claddings, IEEE J Quant Electron,


17.  Rastogi V, Chang K S, Holey optical fiber with circularly distributed holes analyzed by the radial effective-index method, Opt Lett, 28(2003)2449-2451.

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Evaluation of confinement losses in micro-structured optical fibers: an alternative approach.pdf
D K Sharma, H Singh and S M Tripathi



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