Publications

Microwave atomic clocks have traditionally served as the 'gold standard' for precision measurements of time and frequency. However, over the past decade, optical atomic clocks have surpassed the precision of their microwave counterparts by two orders of magnitude or more. Extant optical clocks occupy volumes of more than one cubic...

High dynamic range is a key requirement in advanced microwave photonic systems. We demonstrate compensation of nonlinearities occurring in microwave photonic links using a novel digital nonlinear equalization technique and demonstrate suppression of distortion products by 33 dB with a small number of equalizer coefficients.

We review recent advances in the development of slab-coupled optical waveguide (SCOW) devices, progress toward a flexible photonic integration platform containing both conventional high-confinement and SCOW ultra-low confinement devices, and applications of this technology.

We show that the saturation characteristic of microwave-photonic gain is "superhomogeneous" such that the gain of a weaker tone saturates more rapidly than that of a stronger tone when both signals are transmitted over an intensity-modulated optical link. Using this gain model, we simulate the effect of nonlinear gain saturation...

Microwave photonic (MWP) links with a low noise figure and high dynamic range are required for antenna remoting, radio-over-fiber (RoF), and other advanced applications. MWP links have recently been demonstrated with noise figures approaching 3 dB, without any electrical preamplification, by using low-noise high-power laser sources in conjunction with efficient...

We demonstrate a free-running 3-GHz slab-coupled optical waveguide (SCOW) optoelectronic oscillator (OEO) with low phase-noise (88 dB down from carrier). The SCOW-OEO uses highpower low-noise SCOW components in a single-loop cavity employing 1.5- km delay. The noise properties of our SCOW external-cavity laser (SCOWECL) and SCOW photodiode (SCOWPD) are characterized...

We compare the impact of conventional semiconductor optical amplifiers (SOAs) and high linearity slab-coupled optical waveguide amplifiers (SCOWAs) on the SFDR of carrier-suppressed coherent down-conversion microwave photonic links.

Using adiabatic tapers, hybrid silicon / III-V lasers and amplifiers are integrated with conventional thin (t = 0.25 um) silicon waveguides. Amplifiers have ~12 dB intrachip gain, and similar lasers have thresholds of 35 mA.

We review the development of a new class of high-power, edge-emitting, semiconductor optical gain medium based on the slab-coupled optical waveguide (SCOW) concept. We restrict the scope to InP-based devices incorporating either InGaAsP or InGaAlAs quantum-well active regions and operating in the 1.5-μm-wavelength region. Key properties of the SCOW gain...

We demonstrate a slab-coupled optical waveguide external-cavity mode-locked laser having unique bandedges for the amplifier, modulator and saturable absorber elements. An average output power of 50mW and timing jitter of 254fs is achieved at 1.5-GHz.