Research

Research Overview: It is evident that photonic technology will replace electronic technology in near future. Relatively low power consumption, low latencies, less interference, ultra-compact size, extremely high data-rate and wide bandwidth are the key advantages of photonic-technologies which have the potential to remove almost all the drawbacks of present-day electronic technologies. In addition, it is recently demonstrated that quantum computation can often be realized through photonic devices (where optical states are essentially being used as qubits) in a relatively easier way in comparison with other available technologies such as solid-state, super-conducting, Bose-Einstein Condensate (BEC), nuclear magnetic resonance (NMR), trapped-ion based quantum computing etc. Our primary objective is to design efficient on-chip photonic devices for linear (optical switches, couplers, polarization beam splitters), nonlinear (cavity-soliton and optical frequency-comb) and quantum (multipartite entangled squeezed state generation) photonic applications. We investigate the properties of different optical devices made of silicon, silica, silicon nitride, lithium niobate, aluminium gallium arsenide theoretically, numerically and experimentally.

My Ph. D. Thesis (Defense: Nov. 2019):

Final PhD Thesis Raktim Haldar 14EC91R07 IITKGP Nov 2019.pdf

Fig. 1 (Research): This image summarises different topics of my research. The central theme of my research is to develop integrated photonic chips that will have applications in various quantum technologies—from computing to cryptography. In simple words, we try to make quantum computers using circuits driven by light.

Fig. 2 (Research): A key goal of our research is to create complex quantum states with tunable entanglement—starting from single photons emitted by micropillar quantum dots and guided through integrated photonic chips. This image illustrates the core concept driving our pursuit of scalable quantum technologies.

Fig. 3 (Research): Another research objective of our group at IIT Bhubaneswar is to analyse and characterize different properties of a quantum network and its vulnerability against a broad range of practical attacks with machine learning (ML) algorithm. This artistic illustration explains the core concept of using artificial neural network (ANN) in a fully-connected quantum network spanning intercontinental distances. Inset at the top-left of this image shows an artistic rendition of the quantum frequency comb.

Research Topics:

A. Quantum Photonic Technologies

I. Continuous-variable (CV) Quantum Systems

II. Discrete-variable (DV) Quantum Systems

1. Quantum Frequency Comb (Postdoctoral Research)

A. Implementation of higher-dimensional quantum frequency states in different quantum information processing protocols,

B. Bosonic and Fermionic Quantum walk,

C. Quantum neural network,

2. Linear Optical Devices (Ph.D. & M.Tech.)

A. Off-axis/non-concentric microring resonator (MRR) based compact optical filters,

Related publication: Coming soon...

B. A novel scheme to miniaturize optical devices: Off-shifted asymmetric slot-wave guide based ultra-compact optical couplers and polarization beam splitters,

3. Nonlinear Optical Devices (Ph.D.)

A. Dual-pumped Kerr frequency comb (FC) based robust, synchronous all-optical buffer (OB)

B. Kerr frequency comb with nonlinear losses such as two, three, four -photon absorptions and free-carrier effects

4. Quantum Optical Devices (Ph.D.)

A. Continuous variable (CV) squeezed state generation in periodically poled lithium niobate (PPLN) chip,

B. Bipartite and multipartite entanglement generation in PPLN waveguide array,

Fig. 1. Experimental set-up to generate quantum frequency comb in a silicon chip through spontaneous four-wave mixing (SFWM).

Fig. 2. Kerr frequency comb (manifested as disspative cavity soliton (CS) in temporal domain) driven by a continuous-wave (CW) laser in an integrated photonic platform (here, microring resonator).

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