|
Getting your Trinity Audio player ready...
|
A Next-Generation Photonic Analog-to-Digital Converters (NG-PADC) project by the Indian Institute of Technology, Madras (IIT-Madras) has introduced innovative prototypes that could transform multiple industries. These prototypes can perform instantaneous frequency measurement, generation, and transportation of Radio Frequency (RF) signals through optical techniques. This breakthrough could lead to enhanced digital communication speed, improved satellite communication, better medical imaging, and the development of photonic radars.
Analog-to-digital converters (ADCs) play a pivotal role in creating the next generation of advanced digital receivers. Electronic ADCs (EADCs), however, face a challenge in maintaining vertical resolution when dealing with high bandwidths. To address this issue, two potential solutions are available through Photonics.
When RF signals are modulated on a spectrally rich optical pulsed source, they can be extended in the optical domain using a dispersive medium. This transforms high-frequency RF signals effectively into low-frequency signals. Consequently, this diminishes the input bandwidth requirements of the back-end ADC as many times as the stretch factor of the optical pulse.
The alternative Photonic approach involves using an optical clock whose fluctuations in timing (timing jitter) are much smaller than an electronic clock through a short-pulsed laser. When high bandwidth RF signals are sampled with stable optical clocks, it results in a substantially higher effective number of bits (ENOB) compared to electronic clocks. It has time-stretched photonic ADC with an effective bandwidth 12 times higher than EADC, which enables the digitisation of signals with much better precision.
IIT-Madras’ NG-PADC was developed with support from the IMPRINT programme of the Science, Engineering, Research Board (SERB). The prototypes are equipped with a time-stretched photonic ADC which boasts an effective bandwidth that is 12 times greater than a corresponding EADC. This advancement allows for the sampling of higher bandwidth signals with effectively lower bandwidth EADCs.
The IIT-Madras team has been working on high-bandwidth signals for digital coherent communication where the scaling spectral efficiency is challenging due to the inherent limitations of EADCs in terms of their effective number of bits (ENOB). They are actively searching for solutions to overcome this problem and improve the efficiency of digital coherent communication systems.
According to the team, their meetings with the Defence Research and Development Organisation (DRDO) enabled them to create the solutions because they discovered that radar signal processing is limited by the available electronics.
DRDO is the research and defence wing of the Ministry of Defence. Its aim is to empower India with cutting-edge defence technologies and achieve self-reliance in critical defence technologies and systems. Currently, DRDO is a network of more than 50 laboratories that develop technology in aeronautics, armaments, electronics, combat vehicles, engineering systems, instrumentation, missiles, advanced computing and simulation, special materials, and naval systems.
“We were also approached by our industry partner, with similar requirements. Thus, all these expertise came together for the development of NG-PADC,” the IIT-Madras team explained. The scientists are working with a Hyderabad-based company to make the technology accessible to the public. The outcomes of the NG-PADC project can be applied to telecommunications, defence, medical imaging, and satellite technology.
IIT-Madras has a strong experimental group specialising in fibre lasers and high-speed optical communication. It has also successfully showcased digital communication capabilities at data rates exceeding 500 Gbps.
