Shankar Kumar Selvaraja

High-efficiency grating fiber-chip couplers in wide bandgap III-Nitride Material Platforms Open

P. Sudharshan Phani, Srinivasan Raghavan, Shankar Kumar Selvaraja · 2025

Controlled crystallization of thermal evaporated GST-on-SOI for photonic neuromorphic application Open

Rakshitha Kallega, Roopali Shekhawat, K. Ramesh, Shankar Kumar Selvaraja · 2025

Neuromorphic computing is inevitable in addressing the computing challenges faced by the current computing architecture. A nonvolatile process is one of the key elements in realizing a neuromorphic architecture. Realization of a photonic n…

Large Thermo-Optic Blue Shift in a Silicon Micro-ring Resonator using Fe/Co Bistable Molecule Open

Sujit Kamilya, Aneesh Dash, Viphretuo Mere, Ashutosh Mohanty, Shankar Kumar Selvaraja , et al. · 2025

Phase change materials (PCMs) with distinct optical properties at different phases are promising candidates for programmable photonics, optical communication and photonic computing. In this work, we have studied thermo-optic effect in a PC…

Purcell Enhancement of Spontaneous Emission of a Quantum Emitter on a Waveguide Open

Sushma Gali, Komal Sharma, J. K. Basu, Shankar Kumar Selvaraja · 2024

We investigate the effect of a waveguide on an emitter spontaneous emission in its vicinity. The impact of various possible orientations of an emitter with respect to the waveguide surface is studied through simulations and compared with e…

Efficient Poling‐Free Wavelength Conversion in Thin Film Lithium Niobate Harnessing Bound States in the Continuum Open

Jackson Jacob Chakkoria, Rifat Ahmmed Aoni, Aditya Dubey, Guanghui Ren, Thach G. Nguyen , et al. · 2024

Over the past two decades, there has been a surge of interest in photonic integrated circuits (PICs) to enable low‐cost industrial mass manufacture of miniaturized optical systems while simultaneously improving performance and energy effic…

Passive wavelength selective polarization rotator in a hybrid waveguide platform Open

Rahul K Dash, Shankar Kumar Selvaraja · 2024

Polarization rotation and wavelength filtering are key functionalities used to build complex photonic integrated circuits. Both these functionalities have been demonstrated in various material and device platforms. We propose, for the firs…

Sandwiched hybrid waveguide platform for integrated photonics application Open

Rahul K Dash, Shankar Kumar Selvaraja · 2023

Embedded silicon gratings for high-efficiency light-chip coupling to thin film silicon nitride waveguides Open

Pravin Rawat, Siddharth Nambiar, P. Venkatachalam, Radhakant Singh, Shankar Kumar Selvaraja · 2023

Thin film silicon nitride (<150 nm) waveguide has emerged as a dominant ultra-low-loss platform for many loss-critical applications. While thin-film silicon nitride propagation loss is a crucial characteristic, coupling light between an op…

Highly Oriented PZT Platform for Polarization-Independent Photonic Integrated Circuit and Enhanced Efficiency Electro-Optic Modulation Open

Suraj Suraj, Shankar Kumar Selvaraja · 2023

We demonstrate, for the first time, sputtered PZT as a platform for the development of Si-based photonic devices such as rings, MZI, and electro-optic modulators. We report the optimization of PZT on MgO(002) substrate to obtain highly ori…

3-D poling and drive mechanism for high-speed PZT-on-SOI Electro-Optic modulator using remote Pt buffered growth Open

Suraj Suraj, Shankar Kumar Selvaraja · 2023

In this work, we have demonstrated a novel method to increase the electro-optic interaction in an intensity modulator at the C-band by optimizing the growth methodology of PZT with the metal (Ti/Pt) as a base material and the PZT poling ar…

DFT analysis and demonstration of enhanced clamped Electro-Optic tensor by strain engineering in PZT Open

Suraj Suraj, Shankar Kumar Selvaraja · 2023

We report $\approx$400\% enhancement in PZT Pockels coefficient on DFT simulation of lattice strain due to phonon mode softening.The simulation showed a relation between the rumpling and the Pockels coefficient divergence that happens at -…

Sputter-deposited PZT-on-Silicon Optimization for C-band Electro-Optic Modulation Open

Suraj Suraj, Shankar Kumar Selvaraja · 2023

Ferroelectric materials exhibit interesting electric, mechanical and optical properties. Particularly,tin-film lead zirconium titanate (PZT) has been used as a standard piezo-electric material in micro-electro-mechanical systems. Interesti…

Sandwiched Hybrid Waveguide Platform for Integrated Photonics Application Open

Rahul K Dash, Shankar Kumar Selvaraja · 2023

We propose and demonstrate a hybrid waveguide platform using layered amorphous silicon and silicon nitride. The waveguide offers more degrees of freedom to design waveguides with desired confinement, effective index and polarization birefr…

Polarization independent grating in a GaN-on-sapphire photonic integrated circuit Open

Suraj Suraj, Shashwat Rathkanthiwar, Srinivasan Raghavan, Shankar Kumar Selvaraja · 2023

In this work, we report the realization of a polarization-insensitive grating coupler, single-mode waveguide, and ring resonator in the GaN-on-sapphire platform. We provide a detailed demonstration of the material characterization, device …

Embedded Silicon Gratings for High-efficiency Light-Chip Coupling to Thin Film Silicon Nitride Waveguides Open

Pravin Rawat, Siddharth Nambiar, P. Venkatachalam, Radhakant Singh, Shankar Kumar Selvaraja · 2023

Thin film silicon nitride (75 nm$ of 3dB bandwidth. We present a detailed design strategy, simulation, fabrication and characterization data on the effect of various parameters on the coupling.

Embedded Silicon Gratings for High-efficiency Light-Chip Coupling to Thin Film Silicon Nitride Waveguides Open

Pravin Rawat, Siddharth Nambiar, P. Venkatachalam, Radhakant Singh, Shankar Kumar Selvaraja · 2023

Thin film silicon nitride (75 nm$ of 3dB bandwidth. We present a detailed design strategy, simulation, fabrication and characterization data on the effect of various parameters on the coupling.

On-Chip Chemical Sensing Using Double-slot Silicon Waveguide Open

Sushma Gali, Akshay Keloth, Shankar Kumar Selvaraja · 2023

In this paper, we present refractive index measurement using a double-slot silicon waveguide-based Mach Zehnder interferometer. We present a double-slot waveguide that offers the best sensitivity and limit of detection compared to wire and…

Domain effects on the electro-optic properties of thin-film barium titanate Open

Anupama T. Vasudevan, Shankar Kumar Selvaraja · 2023

On-chip electro-optic modulation is essential to realize complex on-chip optical signal processing. Recent developments in thin-film ferroelectric oxide for high-speed electro-optical modulators have gained considerable interest in underst…

Domain effects on the electro-optic properties of thin-film Barium Titanate Open

Anupama T Vasudevan, Shankar Kumar Selvaraja · 2023

Thin-film ferroelectric oxide materials over the year have been explored for various electronic applications. Recently, the electro-optic properties of these materials have gained considerable interest as an integrated high-speed electro-o…

Domain effects on the electro-optic properties of thin-film Barium Titanate Open

Anupama Vasudevan, Shankar Kumar Selvaraja · 2023

Thin-film ferroelectric oxide materials over the year have been explored for various electronic applications. Recently, the electro-optic properties of these materials have gained considerable interest as an integrated high-speed electro-o…

Thin-film Wafer-Scale Mid-IR Fabry Perot Cavity Gas Sensor Open

Pavithra Rao, Akshay Keloth, Shankar Kumar Selvaraja · 2023

We demonstrate a miniaturized wafer-scale optical gas sensor that combines the gas cell, an optical filter, and integrated flow channels. We present the design, fabrication and characterization of an integrated cavity-enhanced sensor. Usin…

Thin-film wafer-scale mid-IR Fabry Perot cavity gas sensor Open

Pavithra Rao, Akshay Keloth, Shankar Kumar Selvaraja · 2023

We demonstrate a miniaturized wafer-scale optical gas sensor that combines the gas cell, an optical filter, and integrated flow channels. We present the design, fabrication and characterization of an integrated cavity-enhanced sensor. Usin…

Independently Reconfigurable Internal Loss and Resonance Shift in an Interferometer-Embedded Optical Cavity Open

Aneesh Dash, Viphretuo Mere, Shankar Kumar Selvaraja, Akshay Naik · 2022

Optical cavities find diverse uses in lasers, frequency combs, optomechanics, and optical signal processors. Complete reconfigurability of the resonant frequency as well as the loss enables development of generic field programmable cavitie…

Linear and Nonlinear Characterization of broadband integrated Si-rich silicon nitride racetrack ring resonator for on-chip applications Open

Partha Mondal, Priyavarthini Venkatachalam, Radhakant Singh, Sneha Shelwade, Sushma Gali , et al. · 2022

We demonstrate the linear and nonlinear characterization of plasma-enhanced chemical vapor deposited silicon-rich silicon nitride (SRSN) racetrack ring resonator for on-chip application within the telecommunication wavelength range. The SR…

Nonlinear spectral broadening of a dual-carrier electro-optic frequency comb in a graphene oxide cladded silicon-rich nitride hybrid waveguide Open

Partha Mondal, Shankar Kumar Selvaraja · 2022

We demonstrate a detailed theoretical analysis describing the generation of an electro-optic comb (EOC) in the near-IR range through discrete phase and amplitude modulation driven by radio frequency (RF) signal generators. Furthermore, the…

Discovery of Polar Semiconducting Scandium Nitride as an Infrared Plasmon and Phonon-Polaritonic Material Open

Krishna Chand Maurya, Dheemahi Rao, Shashidhara Acharya, Pavithra Rao, Ashalatha Indiradevi Kamalasanan Pillai , et al. · 2022

Interaction of light with collective charge oscillations termed as plasmon-polariton and with polar lattice vibrations termed phonon-polariton is a new frontier in nano-photonics. Traditionally doped-semiconductors and conducting metal oxi…

Independently reconfigurable internal loss and resonance-shift in an interferometer-embedded optical cavity Open

Aneesh Dash, Viphretuo Mere, Shankar Kumar Selvaraja, Akshay Naik · 2021

Optical cavities find diverse uses in lasers, frequency combs, optomechanics, and optical signal processors. Complete reconfigurability of the resonant frequency as well as the loss enables development of generic field programmable cavitie…

Mitigation of carrier induced optical bistability in silicon ring resonators Open

Vadivukkarasi Jeyaselvan, Shankar Kumar Selvaraja · 2021

Common mode disturbance tolerant broadband differential SPDT switch for Ka-band radar Open

Vijay Kumar, Sai Saravanan Govindarajan, Shankar Kumar Selvaraja · 2021

The proposed broadband fully differential single-pole double-throw (SPDT) switch for Ka-band radar with high 1-dB power compression point (Pâ��1dB) and isolation is demonstrated using 0.13 Âµm SiGe BiCMOS technology. In contrast to traditi…

High-efficiency vertical fibre-to-polymer waveguide coupling scheme for scalable polymer photonic circuits Open

A. Kumar, Siddharth Nambiar, Rakshitha Kallega, Praveen Ranganath, Priya Ea , et al. · 2021

Polymer photonic circuits offer a versatile platform for various applications, including communication, sensing and optical signal processing. Though polymers offer broadband, linear and nonlinear optical properties, the coupling between a…

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