Research Areas

High Speed Optical Communication: Focus Areas

High Speed Optical communication testbed at IITM

1.1 Scaling Capacity with High-Order Modulation Formats

We investigate advanced modulation techniques to enhance data transmission capacity. This involves exploring higher-order modulation formats that can effectively carry more information, pushing the boundaries of traditional communication systems.

1.2 Superchannel Transmission via Electro-Optic Modulators

Use of super-channel transmission by harnessing frequency combs generated through electro-optic modulators. This research explores the potential for increased data rates and improved spectral efficiency in optical communication systems.

1.3 Few Mode and Multi-Core Fiber Transmission

This research aims to optimize the efficiency of optical communication by leveraging the unique properties of these fibers, potentially leading to increased data throughput and enhanced system performance.

1.4 Digital Signal Processing Algorithms for Impairment Mitigation

Developing advanced digital signal processing algorithms to mitigate impairments in optical communication. This involves creating algorithms capable of jointly addressing multiple impairments, enhancing the overall robustness and reliability of data transmission.

1.5 Probabilistic Constellation Shaping

This research assesses the effectiveness of shaping signal constellations probabilistically to improve the tolerance of optical communication systems to channel nonlinearities and amplifier-induced nonlinearities.

1.6 Failure Prediction of Deployed Fiber Links- A DSP-based approach

Employing digital signal processing techniques to predict failures in deployed fiber links. This research focuses on developing a robust approach to anticipate and mitigate potential issues in optical fiber links, enhancing the overall reliability and maintenance of communication infrastructure.

1.7 Continuous Variable Quantum Key Distribution

Investigating techniques to enhance secure key rate as well as the transmission distance with Gaussian modulation. This involves usage of MCF and Parametric Amplifier.

2. Microwave Photonics

2.1 Optical Clock with low-timing jitter for Photonic ADC

Development of active harmonic mode-locked fiber lasers at GHz repetition rate for Sub-Nyquist photonic ADC.

2.2 Time- Stretched Photonic Analog- Digital Converter

Developing a time-stretch photonic front to reduce the bandwidth requirements of the back-end electronic ADC as many times as the stretch factor of the optical pulse.

2.3 Sub-Nyquist Photonic Analog- Digital Converter

Development of Sub-Nyquist PADC with a bandwidth of 500 MHz at S (2 - 4 GHz), C (4 - 8 GHz) and X (8 - 12 GHz) - bands.

2.4 Analog radio over fiber

Analog radio over fiber technologies with direct, external modulation schemes, and upconversion schemes for mmWave 5G, radar, and satellite applications.

2.5 Bias controller

The bias point of Lithium niobate (LN) Mach Zehnder modulators (MZM) drift over time. We investigate dither-based and dither-free, any-point multi-channel bias control system for single channel and DWDM systems.

3. Optical Signal Processing

DSP-free nonlinearity and dispersion compensation using OPCs

Several nonlinear effects are explored to mitigate impairments and develop an all-optical device which is capable of supporting high-speed optical communication

Distortion-less amplification using semiconductor optical amplifiers

Employing holding beam (HB) to reduce amplitude and nonlinear phase distortions incurred while amplifying high speed optical signal using SOA and thereby targeting distortion-less ultra-wide amplification.

Phase sensitive / parametric amplifiers

The Noise figure of an amplifier contributes to the total noise figure of a long haul fiber optic link. A nonlinear medium can be employed to function as a parametric and/or phase sensitive amplifier which can have a noise figure of less than 3 dB.

4. Fiber Lasers

4.1 Laser Phase Noise Analyzer

Laser phase noise : critical for qualifying narrow linewidth lasers used in high speed optical communication, LIDAR, optical clocks. Laser phase noise analyzer accurately estimates the laser phase/frequency noise PSD from very low frequency offsets.