Searcharxiv⌕ Search

arXiv subjects

Mohammad E. Mousa-Pasandi

Publications and source records attributed to Mohammad E. Mousa-Pasandi.

3 recordsLinked to original sources
arXiv2026

Wavelength-diverse transmission for turbulence-resistant free-space optical communication

Free-space optical communication (FSOC) links are susceptible to outages caused by atmospheric turbulence-induced fading. Wavelength diversity can mitigate fading by transmitting correlated information across substantially uncorrelated channels. In this study, we demonstrate a wavelength diversity system to mitigate the effects of turbulence on a signal propagated in free space. A modified polarization-multiplexed coherent optical transceiver transmits a 56.8 GBaud signal at a client rate of 200 Gbps across two carrier frequencies within the C-band over a bench-top free-space link with a turbulence emulator. Two synchronized single-wavelength coherent receivers capture the received waveforms at each carrier frequency, which are subsequently digitally combined using maximal ratio combining for offline processing. Our results demonstrate a reduction in outage probability by nearly a factor of 20 compared to the single carrier transmission scenario. Finally, we observe fading-dependent correlation between wavelengths in the C-band, which is exploited to reduce the outage probability by 86%.

physics.optics↗
arXiv2024

Coherent Optical Modems for Full-Wavefield Lidar

The advent of the digital age has driven the development of coherent optical modems--devices that modulate the amplitude and phase of light in multiple polarization states. These modems transmit data through fiber optic cables that are thousands of kilometers in length at data rates exceeding one terabit per second. This remarkable technology is made possible through near-THz-rate programmable control and sensing of the full optical wavefield. While coherent optical modems form the backbone of telecommunications networks around the world, their extraordinary capabilities also provide unique opportunities for imaging. Here, we repurpose off-the-shelf coherent optical modems to introduce full-wavefield lidar: a type of random modulation continuous wave lidar that simultaneously measures depth, axial velocity, and polarization. We demonstrate this modality by combining a 74 GHz-bandwidth coherent optical modem with free-space coupling optics and scanning mirrors. We develop a time-resolved image formation model for this system and formulate a maximum-likelihood reconstruction algorithm to recover depth, velocity, and polarization information at each scene point from the modem's raw transmitted and received symbols. Compared to existing lidars, full-wavefield lidar promises improved mm-scale ranging accuracy from brief, microsecond exposure times, reliable velocimetry, and robustness to interference from ambient light or other lidar signals.

cs.CV↗