Photonic radar is a technique by which

radar Radar is a system that uses radio waves to determine the distance ('' ranging''), direction ( azimuth and elevation angles), and radial velocity of objects relative to the site. It is a radiodetermination method used to detect and track ...

may be produced and analysed with the help of

photonics Photonics is a branch of optics that involves the application of generation, detection, and manipulation of light in the form of photons through emission, transmission, modulation, signal processing, switching, amplification, and sensing. E ...

rather than traditional

RF engineering Radio-frequency (RF) engineering is a subset of electrical engineering involving the application of transmission line, Waveguide (electromagnetism), waveguide, Antenna (radio), antenna, radar, and Electromagnetic radiation, electromagnetic fiel ...

techniques. The frequency of the radar is still in the RF, but lasers are used to create and analyse the RF signals with high precision.

China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...

Russia Russia, or the Russian Federation, is a country spanning Eastern Europe and North Asia. It is the list of countries and dependencies by area, largest country in the world, and extends across Time in Russia, eleven time zones, sharing Borders ...

and

India India, officially the Republic of India, is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area; the List of countries by population (United Nations), most populous country since ...

have active research programs to equip

fighter aircraft Fighter aircraft (early on also ''pursuit aircraft'') are military aircraft designed primarily for air-to-air combat. In military conflict, the role of fighter aircraft is to establish air supremacy, air superiority of the battlespace. Domina ...

with photonic radar. The potential benefits are longer range of detection, better position sensing, and 3D model target reconstruction. In one study, a test device could resolve objects as small as 3 x 4 cm (1.2 x 1.6 in), much smaller than traditional radar.

Overview of operation

laser diode file:Laser diode chip.jpg, The laser diode chip removed and placed on the eye of a needle for scale A laser diode (LD, also injection laser diode or ILD or semiconductor laser or diode laser) is a semiconductor device similar to a light-emittin ...

is used to generate an optical signal that is modulated by a linearly-

chirp A chirp is a signal in which the frequency increases (''up-chirp'') or decreases (''down-chirp'') with time. In some sources, the term ''chirp'' is used interchangeably with sweep signal. It is commonly applied to sonar, radar, and laser syste ...

ed low frequency signal. This modulated optical signal is then split, with one part immediately converted to an electronic signal at 4 times the frequency of the original modulating signal. This waveform is then amplified, emitted via a standard antenna, and then received again via another standard antenna. The second half of the modulated optical signal is further modulated by the reflected signal, and then converted to an electronic signal. This electronic signal is sent through a low-pass filter and finally digitized via an

analog-to-digital converter In electronics, an analog-to-digital converter (ADC, A/D, or A-to-D) is a system that converts an analog signal, such as a sound picked up by a microphone or light entering a digital camera, into a Digital signal (signal processing), digi ...

. The resulting digital waveform can be processed to recover the delay between the transmitted and reflected signal, and thus the distance to the target. The entire system may be operated in real-time to allow high-speed

target acquisition Target acquisition is the detection and identification of the location of a target in sufficient detail to permit the effective employment of lethal and non-lethal means. The term is used for a broad area of applications. A "target" here is an e ...

Applications

Novel potential applications include non-invasive patient vital sign monitoring using a photonic chip small enough to include in a phone. On 29 June 2025, India's Electronics and Radar Development Establishment, under

DRDO The Defence Research and Development Organisation (DRDO) is an agency under the Department of Defence Research and Development in the Ministry of Defence of the Government of India, charged with the military's research and development, headqu ...

, completed the fabrication & development of a photonic radar which will replace or complement the conventional AESA radars for fighter jets and ground based systems. Within the next few months, the system will undergo extensive trials onboard stationary testbeds and then onboard

UAVs An unmanned aerial vehicle (UAV) or unmanned aircraft system (UAS), commonly known as a drone, is an aircraft with no human pilot, crew, or passengers onboard, but rather is controlled remotely or is autonomous.De Gruyter Handbook of Drone ...

and naval vessels. It use multiple photonic transmitter/receiver modules. In 2022 tests, the prototype version of photonic radar was able to image small objects, measuring just , as they moved on a rotating plate.

References

{{reflist Photonics