# Laser radio transmitter

## TL;DR

This paper demonstrates a novel compact radio frequency transmitter using a semiconductor laser frequency comb, enabling wireless communication and synchronization through integrated laser and antenna design.

## Contribution

It introduces a new design that couples laser frequency combs with integrated antennas for wireless RF transmission and reception, a significant advancement over traditional radio transmitters.

## Key findings

- Laser beating generates RF current within the laser cavity.
- Redesigning the laser contact enables coupling to an external antenna.
- Laser modulation can encode signals onto the RF carrier.

## Abstract

Since the days of Hertz, radio transmitters have evolved from rudimentary circuits emitting around 50 MHz to modern ubiquitous Wi-Fi devices operating at gigahertz radio bands. As wireless data traffic continues to increase there is a need for new communication technologies capable of high-frequency operation for high-speed data transfer. Here we give a proof of concept of a new compact radio frequency transmitter based on a semiconductor laser frequency comb. In this laser, the beating among the coherent modes oscillating inside the cavity generates a radio frequency current, which couples to the electrodes of the device. We show that redesigning the top contact of the laser allows one to exploit the internal oscillatory current to drive an integrated dipole antenna, which radiates into free space. In addition, direct modulation of the laser current permits encoding a signal in the radiated radio frequency carrier. Working in the opposite direction, the antenna can receive an external radio frequency signal, couple it to the active region and injection lock the laser. These results pave the way to new applications and functionality in optical frequency combs, such as wireless radio communication and wireless synchronization to a reference source.