Electrically Driven Reprogrammable Vanadium Dioxide Metasurface Using Binary Control for Broadband Beam Steering.

Resonant optical phased arrays are a promising way to reach fully reconfigurable metasurfaces in the optical and near-infrared (NIR) regimes with low energy consumption, low footprint, and high reliability. Continuously tunable resonant structures suffer from inherent drawbacks such as low phase range, amplitude-phase correlation, or extreme sensitivity that makes precise control at the individual element level very challenging. We computationally investigate 1-bit (binary) control as a mechanism to bypass these issues.

Expansion and phase correlation of a wavelength tunable gain-switched optical frequency comb.

A novel scheme for the expansion and phase correlation of a wavelength tunable gain-switched optical frequency comb (OFC) is presented. This method entails firstly combining two gain-switched OFCs and expanding them using a phase modulator. Subsequently, the phase correlation between all the comb lines is induced through four-wave mixing (FWM) in a semiconductor optical amplifier (SOA).

Experimental demonstration of 12.5 GHz wideband chaos in symmetric dual-port EDFRL.

We study the dynamics of chaos in a dual-port erbium-doped fiber ring laser (EDFRL). The laser consists of two erbium-doped fibers, intracavity filters at 1549.32 nm, isolators, and couplers.

Simple dispersion estimate for single-section quantum-dash and quantum-dot mode-locked laser diodes.

The optical outputs of single-section quantum-dash and quantum-dot mode-locked lasers (MLLs) are well known to exhibit strong group velocity dispersion. Based on careful measurements of the spectral phase of the pulses from these MLLs, we confirm that the difference in group delay between the modes at either end of the MLL spectrum equals the cavity round-trip time. This observation allows us to deduce an empirical formula relating the accumulated dispersion of the output pulse to the spectral extent and free-spectral range of the MLL.

320 Gb/s all-optical clock recovery and time de-multiplexing after transmission enabled by single quantum dash mode-locked laser.

We report, to the best of our knowledge, the first demonstration of 320 Gb/s all-optical clock recovery and all-optical time de-multiplexing after 51 km transmission by exploiting single-quantum dash mode-locked laser diode (QD-MLLD). Based on injection locking of the QD-MLLD, the 40 GHz synchronized optical clock pulses were recovered from the 320 Gb/s with a pulse width of 1.9 ps and timing jitter of 135 fs, which allowed directly time de-multiplexing of 320-40 Gb/s without additional complex optoelectronic circuitry.

Finite element method analysis of band gap and transmission of two-dimensional metallic photonic crystals at terahertz frequencies.

Photonic band gap and transmission characteristics of 2D metallic photonic crystals at THz frequencies have been investigated using finite element method (FEM). Photonic crystals composed of metallic rods in air, in square and triangular lattice arrangements, are considered for transverse electric and transverse magnetic polarizations. The modes and band gap characteristics of metallic photonic crystal structure are investigated by solving the eigenvalue problem over a unit cell of the lattice using periodic boundary conditions.

Method to improve the noise figure and saturation power in multi-contact semiconductor optical amplifiers: simulation and experiment.

The consequences of tailoring the longitudinal carrier density along the active layer of a multi-contact bulk semiconductor optical amplifier (SOA) are investigated using a rate equation model. It is shown that both the noise figure and output power saturation can be optimized for a fixed total injected bias current. The simulation results are validated by comparison with experiment using a multi-contact SOA.

40 GHz mode-beating with 8 Hz linewidth and 64 fs timing jitter from a synchronized mode-locked quantum-dash laser diode.

Linewidth narrowing of the radio frequency beat-tones and the optical-modes is experimentally investigated in a ∼40 GHz quantum-dash mode-locked laser diode subject to optical injection of 10 GHz pulses. In comparison to the 75 kHz linewidth exhibited by the beat-tones in passive mode-locking conditions, a remarkable reduction to less than 8 Hz is achieved when the laser is under optical injection. From this beat-tone signal, an integrated root-mean-square timing jitter of 64 fs is calculated.

Impact of bias current distribution on the noise figure and power saturation of a multicontact semiconductor optical amplifier.

We present an experimental investigation of a multicontact semiconductor optical amplifier. This first-generation device allows for direct control of the carrier density profile along the length of the waveguide. This is used to control the device noise figure, with a minimum value of 5 dB observed at a gain of 15 dB for an optimum carrier density profile.

Experimental investigation of harmonic and subharmonic synchronization of 40 GHz mode-locked quantum-dash laser diodes.

Synchronization of a 40 GHz quantum-dash mode-locked (ML) Fabry-Perot laser diode with optically injected pulse streams is experimentally studied. Injected signals consist of nonmodulated and modulated trains of 1.6 ps pulses at various repetition rates, ranging from 10 to 160 GHz and 10 to 160 Gbps, respectively.

Timing-jitter, optical, and mode-beating linewidths analysis on subpicosecond optical pulses generated by a quantum-dash passively mode-locked semiconductor laser.

Timing-jitter measurements in optically generated subpicosecond pulses by a quantum-dash passively mode-locked semiconductor laser as a function of the bias current are reported. All the measurements are retrieved from a second-harmonic-generation frequency-resolved optical gating system. A decreasing trend in the pulse width and the associated timing jitter is found with the bias current.

Sub-picosecond pulse generation by 40-GHz passively mode-locked quantum-dash 1-mm-long Fabry-Pérot laser diode.

Optical pulses at a repetition rate of 39.8 GHz have been observed in a dc-biased passively mode-locked quantum-dash Fabry-Pérot laser diode. The pulses generated by this diode are studied in the temporal and spectral domains using a second harmonic generation frequency-resolved optical gating system.

Polarization dependence of non-linear gain compression factor in semiconductor optical amplifier.

We investigate the power and the polarization dependence of the intraband dynamics in a bulk semiconductor optical amplifier using both a 2.5-ps pump-probe experimental set-up in contra-propagation and a theoretical model. Our model is based on the rate equations and takes into account the polarization dependence of the gain.