Towards high-power, high-coherence, integrated photonic mmWave platform with microcavity solitons

Abstract

Millimetre-wave (mmWave) technology continues to draw great interest due to its broad applications in wireless communications, radar, and spectroscopy. Compared to pure electronic solutions, photonic-based mmWave generation provides wide bandwidth, low power dissipation, and remoting through low-loss fibres. However, at high frequencies, two major challenges exist for the photonic system: the power roll-off of the photodiode, and the large signal linewidth derived directly from the lasers. Here, we demonstrate a new photonic mmWave platform combining integrated microresonator solitons and high-speed photodiodes to address the challenges in both power and coherence. The solitons, being inherently mode-locked, are measured to provide 5.8 dB additional gain through constructive interference among mmWave beatnotes, and the absolute mmWave power approaches the theoretical limit of conventional heterodyne detection at 100 GHz. In our free-running system, the soliton is capable of reducing the mmWave linewidth by two orders of magnitude from that of the pump laser. Our work leverages microresonator solitons and high-speed modified uni-traveling carrier photodiodes to provide a viable path to chip-scale, high-power, low-noise, high-frequency sources for mmWave applications.

Coherent Photonic Terahertz Transmitters Compatible with Direct Comb Modulation

“…Furthermore, if the comb produces near transform-limited pulses, this scheme can increase -compared to the two-line modulation described in the previous section -the emitted THz power for a fixed level of optical power (or photocurrent). A theoretical gain of up to 6 dB was reported here 8 with experimental results in reference 9 matching quite well this theoretical value. Calculations in these two references focused on the case where wireless generation is performed at the fundamental repetition frequency.…”

Visualising the heart of chaos

“…Through their visualisation method, the authors shed light on the exact electromagnetic field position in dielectric microcavities. In nonlinear processes, it is this field distribution that determines the ultimate efficiency of the process, and knowledge of this will help to engineer phase-matching for processes such as mmWave generation 6,16 and microcomb generation 17 A chaotic mode in an oval microresonator is probed at its resonant frequency (left). When the microresonator is illuminated by a blue laser at a minimum of the mode, the resulting change in index has little effect upon the mode, and it remains at f 0 (a).…”

Effect of Phase Noise on the Optical Millimeter-Wave Signal in the DWDM-RoF System

“…Different applications, such as complementing terrestrial RANs with unmanned arial vehicles (UAVs), can be cost-effective and flexible strategies with the 5G radio access networks, as reported in [2]. Furthermore, the mm-wave technology is capable of meeting the increasing demands of wireless applications [3][4][5][6]. However, in the electrical domain, the generation of mm waves with high frequency remains a challenge due to the current restrictions on frequency responses of electronic devices and equipment.…”