Research Contributions

Microwave photonic combines the application of microwave techniques to optical communications and optical techniques to RF and microwaves. Two application areas are antenna beam forming and high speed optical modulation. We analysed curved integrated optic waveguides to achieve microwave phase-shifts. Using electo-optic switches to join these curved waveguides we obtain switched delay line useful for antenna beam forming and beam steering. Using interference of closely spaced laser frequencies in optical waveguide couplers we create high speed modulators like BPSK and QPSK.

Implementation of quantum information functions is a topic of significant interest where photonic devices are considered to play an important role. In our recent work we addressed we investigate the role of quantum indistinguishability in random number generation, that of quantum temporal correlations in a specific device-independent scenario as applied to prepare-and-measure QKD schemes, and further that of quantum non-locality and counter-factuality as applied to quantum information splitting and certificate authorization. Integrated optic devices for quantum logic gates and high dimension QKD are also studied.

Significant Achievement during this period:

Experimental realization of photonic bandgap structures, with sub-micrometer dimensions on silicon, and fabrication of long channel waveguides and gratings in Silicon for light coupling to integrated optic devices.

PBG based ring resonator                IO grating and tapered waveguide Measurement Setup

Biosensors and biochemical applications is a potential application ground for integrated optics. Presently cladding layers of integrated optic circuits is manipulated to created biosensor applications. Knowledge and requirement of health care applications will enhance the development of these devices. This aspect will be included along with studies in basic integrated optics. Also biological phenomena are a source of ideas for engineering. New engineering devices and systems could be developed to imitate biological systems but with greater efficiency, speed and control.

Quantum techniques are considered the future of communications and information engineering. They are natural, powerful and indispensable. Photonics is the route to implementing quantum information functions. Miniaturization is necessary for practical applications. New integrated optic structures can perform quantum functions effectively, for example coupled cavities of photonic band-gap structures. Implementation of the already established algorithms and theories is a major activity in the field.

Inverse Design techniques automate the design process of photonic devices for a given target and conditions, unlike the conventional method in which the design process is guided by human intuition and systematic fine-tuning. It is capable of exploring the full space of fabricable devices. This technique consists of a numerical solver of maxwell equations with optimization and machine learning algorithms.

Integrated photonic circuits provide a sustainable alternative to electronic circuits offering high bandwidth, a small footprint, and low power consumption. This can be further scaled by multipurpose photonic chips, which can be programmed to manage multiple functions simultaneously using dynamic routing algorithms. These chips can be utilized in a wide range of applications, including 5G/6G communication, intelligent transceivers and switches, hardware accelerators for neural networks, LIDAR and aerospace surveillance and communications. These programmable photonic circuits rely on MZIs and phase shifters to implement routing, independent amplitude, and phase change. Some exciting applications using these chips can be the implementation of uplink and downlink in the same circuit for optical communication, photonic radars, high throughput biosensors, arbitrary optical filters etc. For decades electronic FPGA circuits have shaped the communication industry; the next revolution will be brought around by these programmable photonic integrated circuits.