Demonstration of high-frequency self-pulsing oscillations in an active silicon micro-ring cavity.

We experimentally investigated the self-pulsing (SP) oscillations induced by the thermo-optic, free carrier, and Kerr nonlinear effects in integrated active silicon microring resonators. We demonstrate high frequency self-pulsing oscillations (up to 30 MHz) by applying a few millivolts of reverse bias voltage to the PIN junction of the active cavity. We illustrate that the shape of those oscillations (i.

On-chip lateral Si:Te PIN photodiodes for room-temperature detection in the telecom optical wavelength bands.

Photonic integrated circuits require photodetectors that operate at room temperature with sensitivity at telecom wavelengths and are suitable for integration with planar complementary-metal-oxide-semiconductor (CMOS) technology. Silicon hyperdoped with deep-level impurities is a promising material for silicon infrared detectors because of its strong room-temperature photoresponse in the short-wavelength infrared region caused by the creation of an impurity band within the silicon band gap. In this work, we present the first experimental demonstration of lateral Te-hyperdoped Si PIN photodetectors operating at room temperature in the optical telecom bands.

Theoretical investigation of a photonic-assisted instantaneous frequency measurement with a tunable measurement range and resolution by adjusting the chirp parameter of an optical intensity modulator.

The chromatic dispersion-based frequency-to-power mapping approach is often used in microwave photonic (MWP) instantaneous frequency measurement (IFM) receivers. A mechanism to tune the measurement range and resolution of these MWP IFM receivers by adjusting the chirp parameter of their optical intensity modulators is proposed and demonstrated. In particular, an MWP IFM receiver with a tunable measurement range and resolution based on a chirp-adjustable dual-drive Mach-Zehnder modulator (DDMZM) and two dispersive mediums is proposed and theoretically investigated.

Optical single sideband polarization modulator with tunable optical carrier-to-sideband ratio and its applications in microwave photonic phase shifter and optical frequency shifter.

In this paper, a novel scheme to implement an optical single sideband (OSSB) polarization modulator (PolM) is proposed and theoretically investigated. The proposed structure contains two dual-drive Mach-Zehnder modulators inside a Mach-Zehnder interferometer whose input/output optical Y-couplers are replaced by two optical polarization beam splitters/polarization beam combiners. It is shown that by applying four equal power radio-frequency signals with appropriate phases, an OSSB polarization-modulated signal is generated.

Tunable microwave-photonic filter using frequency-to-time mapping-based delay lines.

A new implementation of microwave-photonic filters (MPFs) based on tunable optical delay lines is proposed and demonstrated. The variable delay is based on mapping of the spectral components of an incoming waveform onto the time domain, the application of linearly-varying temporal phase offsets, and an inverse mapping back to the frequency domain. The linear phase correction is equivalent to a frequency offset, and realized though suppressed-carrier single-sideband modulation by a radio-frequency sine wave.

Fully-tunable microwave photonic filter with complex coefficients using tunable delay lines based on frequency-time conversions.

A fully electrically tunable microwave photonic filter is realized by the implementation of delay lines based on frequency-time conversion. The frequency response and free spectral range (FSR) of the filter can be engineered by a simple electrical tuning of the delay lines. The method has the capability of being integrated on a silicon photonic platform.

Continuously variable long microwave-photonic delay of arbitrary frequency-chirped signals.

A generic method for the continuously variable, long microwave-photonic delay of the impulse response of arbitrarily chirped waveforms is proposed and demonstrated. Nonlinear-frequency-modulated waveforms of 500 MHz bandwidth are delayed by tens of nanoseconds. The principle relies on the specific phase-time relations of the waveforms, and is applicable to chirped pulses of arbitrary durations, central radio frequencies, and bandwidths.

Frequency domain aperture for the gain bandwidth reduction of stimulated Brillouin scattering.

In this Letter, we propose a novel method based on the inhomogeneous Brillouin gain saturation to reduce the gain bandwidth significantly below its natural value. Based on our first experiments, we report a decrease of the bandwidth in a standard single mode fiber down to 3 MHz.

Quasi-light-storage enhancement by reducing the Brillouin gain bandwidth.

The quasi-light-storage (QLS) is a method for the variable and almost distortion free storage of optical data which is based on stimulated Brillouin scattering (SBS). The natural gain bandwidth of SBS limits the storage time of this method to up to 100 ns. We overcome this limit by the superposition of the SBS gain bandwidth with two losses.

Brillouin scattering gain bandwidth reduction down to 3.4MHz.

We present a simple method for the stimulated Brillouin scattering (SBS) gain bandwidth reduction in an optical fiber. We were able to reduce the natural bandwidth of 20 MHz to around 3.4 MHz by a superposition of the gain with two losses produced by the same source.

Quasi-Light-Storage based on time-frequency coherence.

We show a method for distortion-free quasi storage of light which is based on the coherence between the spectrum and the time representation of pulse sequences. The whole system can be considered as a black box that stores the light until it will be extracted. In the experiment we delayed several 5 bit patterns with bit durations of 500ps up to 38ns.