Wide-range, high-precision multiple microwave frequency measurement using a chip-based photonic Brillouin filter

Abstract

Spectrum analysis is a key functionality in modern radio frequency (RF) systems. In particular, fast and accurate estimation of multiple unknown RF signal frequencies over a wide measurement range is crucial in defense applications. Although photonic techniques benefit from an enhanced frequency estimation range along with reduced size and weight relative to their RF counterparts, they have been limited by a fundamental trade-off between measurement range and accuracy. Here, we circumvent this trade-off by harnessing the photon and phonon interactions in a photonic chip through stimulated Brillouin scattering, resulting in an accurate estimation of multiple RFs of up to 38 GHz with a record-low error of 1 MHz.

Invited Article: Acousto-optic finite-difference frequency-domain algorithm for first-principles simulations of on-chip acousto-optic devices

“…Depending on the choice of PML and conditioning of the Jacobian matrix in Eq. (19), one may need to precondition the Jacobian matrix as detailed in Refs. 27 and 28 to obtain solutions with accelerated convergence.…”

“…[1][2][3] Traditionally, SBS has been studied extensively in fiber-optic devices in order to inhibit undesired nonlinear effects induced by SBS. [1][2][3][4] More recently, SBS has been tailored for micron-scale on-chip devices, 2,3,[5][6][7][8][9][10] where it is considered to be an attractive candidate in the creation of lasers with ultra-narrow bandwidths, [11][12][13][14] gigahertz frequency combs, 15,16 slow light, 17 and on-chip signal processing devices such as the microwave photonic filter 18,19 and optical isolators. [20][21][22][23] Given the wide range of devices that can harness SBS, it is important to develop general numerical techniques that can facilitate the device design process.…”

“…As such, when designing fiber-optic and on-chip acousto-optic devices, researchers typically adopt a mode-expansion technique, which calculates the optical and acoustic modes independently and then treats the acousto-optic coupling perturbatively using the coupled mode theory. [5][6][7][8][9][10][11][12][13]16,[18][19][20][21] Unfortunately, the application of coupled mode theory is not exact and becomes difficult for complex geometries, which may support a large number of interacting modes. Therefore, in order to accurately and realistically perform first-principles simulations of a general class of acousto-optic devices, there is an urgent need to develop a computational algorithm to efficiently and exactly simulate the interactions between optical and acoustic waves.…”

Simultaneous Multi-Channel Microwave Photonic Signal Processing

“…Over the years, applications of MWP have evolved to include, amongst others, communications (e.g., to support the interface of wireless and optical communications, as well as for emerging 5G communications and the Internet of Things), sensing (e.g., to enhance resolution and increase the interrogation speed of conventional fiber optic sensor systems), and instrumentation (e.g., wideband signal characterization). To support these various applications, numerous functions are required, such as photonic generation of arbitrary waveforms, e.g., microwave, millimeter wave, and THz signals [4,5]; photonic processing of microwave signals, e.g., filtering, time delay, and phase shifting [6][7][8]; and photonic characterization of microwave signals, e.g., spectrum analysis and instantaneous frequency measurement (IFM) [9,10].…”

Orbital angular momentum mode division filtering for photon-phonon coupling

“…More recently, significant progress in nanofabrication techniques has enhanced our capability to shape and control light-matter interactions, as a consequence, now photon-phonon interactions can be manipulated to an unprecedented degree, ranging from photonic and phononic crystals, chalcogenide and silicon waveguides to dual-nanoweb fiber6789101112. These tailorable interactions provide a host of integrated signal processing functions having no all-optical analog1314151617, and in consequence SBS science has been experiencing a revival in recent years.…”