IEEE Photonics Technology Letters

An in-band optical signal-to-noise ratio (OSNR) monitoring technique based on a Michelson fiber interferometer and a linear polarizer is presented in this letter. OSNR values of up to 25±0.5 dB were measured for 10-G nonreturn-to-zero-differential phase-OOK (NRZ-OOK) and NRZ-differential phase-shift keyed (NRZ-DPSK) signals without prior knowledge of the signal coherence properties. Measure... View full abstract»

We investigate a multilayer vertical stacking scheme for use in the Silicon Nitride-based low-loss waveguide platform. In this letter, we use common fabrication techniques to produce test structures for probing the interactions between vertically separated parallel waveguide planes and the characteristics of vertical directional couplers. Single-mode and multimode waveguide geometries are investig... View full abstract»

Experimental and simulation work, presented in this letter, demonstrates for the first time how the monolithic integration of two single-mode lasers in a master-slave configuration, can substantially increase the achievable bit rate of a direct modulation adaptively modulated optical orthogonal frequency-division multiplexing (AMO-OFDM) system. The Levin-Campello algorithm is applied to select the... View full abstract»

We investigated the dependency of plasmon-enhanced luminescence on the refractive index of a dielectric substrate of Ag nanoparticles. We used silicon dioxide (n=1.456) and indium tin oxide (n=1.8) as bottom layers for Ag nanoparticles. Due to the extinction spectra of Ag nanoparticles on substrates with high refractive indexes, the localized surface plasmon band moved toward a longe... View full abstract»

Owing to its low transmitter complexity and low sensitivity to nonlinear impairments, phase noise, and frequency offset, the single carrier system with frequency domain equalization (SC-FDE) is of interest for high-bit-rate optical transmission. In this letter, we experimentally demonstrate a 8×40-Gb/s optical coherent polarization-multiplexed SC-FDE over 2080-km fiber transmission using no... View full abstract»

To enhance the internal quantum efficiency of GaInAsP/InP lateral current injection (LCI) lasers, we adopted a structure consisting of five uniformly distributed quantum-wells (QWs). A differential quantum efficiency of 59% and an internal quantum efficiency of 70% were obtained for a cavity length of 750 μm, the latter value is almost twice that of an LCI-Fabry-Pérot laser with a c... View full abstract»

We demonstrate a multichannel time-multiplexed radio-frequency arbitrary waveform generator. The system combines a switching scheme of multiwavelength optical frequency combs with a novel 2-D line-by-line pulse shaper featuring broad bandwidth operation over large temporal windows. Switching times within a clock period of 200 ps among the four channels is successfully achieved. With finer pulse sh... View full abstract»

We apply higher-order interface conditions to full-vectorial finite-difference mode analysis of circularly symmetric waveguides. It is very efficient in analyzing complex structures that analytic methods may face some difficulties in dealing with them, such as structures with absorption, leakage, multilayers, nonlinearity, and applications in beam propagation. A step-index optical fiber is modeled... View full abstract»

We demonstrate the monolithic integration of a buried heterostructure semiconductor optical amplifier (SOA) and a deep ridge PIN photodiode for high-speed on-off keying links at 1.55 μm. The structure allows separate optimization of the SOA and the photodiode. The integrated receiver presents simultaneously a peak responsivity of 88 A/W with a low polarization dependence loss (<; 1 dB), ... View full abstract»

A hybrid Si3N4-Er/Yb silicate waveguide structure was fabricated by depositing 400-nm-thick Er/Yb silicate film on a 2.4-μm-wide and 250-nm-thick Si3N4 strip. Benefiting from the low loss of the Si3N4 materials, the propagation loss of the hybrid waveguide was as low as 3.2 ±0.3 dB/cm. A 3.1-dB signal enhancement was o... View full abstract»

In this letter, we numerically investigate the statistical properties of the optical chaos hiding a digital message in secure transmission schemes. It is found that even if chaos statistics are usually not Gaussian, the statistics of the residual chaos, over the extracted message, are nearly Gaussian. Thus, assessing the bit-error rate from the Q parameter, as it is often done in the numerical ana... View full abstract»

Temperature-dependent lasing characteristics of transverse single-mode GaAs-based InAs submonolayer (SML) quantum-dot (QD) lasers are investigated. The SML QD lasers, when operated under continuous wave (cw) conditions up to 65°C, exhibit a high characteristic temperature (T0) of around 101 K. The temperature-dependent net modal gain is also studied using the Hakki-Paoli m... View full abstract»

A CdZnO/n-ZnO multiple-quantum-well (QW) light-emitting diode (LED), with the QWs and n+-ZnO capping layer grown with molecular beam epitaxy on p-GaN, which is grown with metal-organic chemical vapor deposition, is fabricated and characterized. Because of the weak carrier localization mechanism in the ZnO-based LED, its defect emission is quite strong and dominates the LED output when i... View full abstract»

We present a self-aligned optical all integrated measurement section on a single substrate consisting of an organic light-emitting diode (OLED) as light source and an organic photodetector (OPD), both fabricated by spin-coating. Areas of the layers, that are not required, are removed by an oxygen plasma treatment. No additional shadow mask is used in this self-aligned structuring process as the me... View full abstract»

Plane-wave expansion calculations show that a broad higher-order bandgap can be formed in all-solid honeycomb photonic bandgap fibers, different from fibers based on the typical triangular lattice. Both density of states plots and Bloch-mode field distributions reveal that the higher-order bandgap results from a re-ordering of the linearly polarized modes that form the cladding states, that is, th... View full abstract»

A photonic-integrated circuit consisting of a 1.3-μm quantum-dot laser and Si3N4 single-mode tapered waveguide, suitable for high temperature operation, is demonstrated. The laser active region incorporates p-doping, tunnel injection, and a superlattice barrier. The temperature dependence of the threshold current of the discrete laser is characterized by T0 ... View full abstract»

We propose and simulate a device based on hybrid channel waveguide and photonic crystal waveguide (PCW) for THz-wave difference-frequency generation (DFG) from near-infrared light sources. The proposed structure guides the two pumps by a Ti-diffused LiNbO3 channel waveguide, and confines the DFG THz wave tightly with LiNbO3 PCW. By proper use of the PCW, both continuous phase... View full abstract»

We report the superbroadband photoluminescence extending from 1.3 to 1.7 μm in Neodymium(Nd3+)/Thulium(Tm3+)/Erbium(Er3+) codoped fluorotellurite glasses under 793 nm excitation. This superbroadband luminescence is contributed by the Nd3+:4F3/2→4I13/2, Tm3+:3H4... View full abstract»

We report a passively mode-locked picosecond ytterbium-doped fiber laser operating in the normal dispersion regime, tunable over 70 nm around 1.05 μm. Mode-locking operation is achieved through a free-space coupled semiconductor saturable absorber. An external grating in Littrow configuration is used for both tuning and mode-locked stabilization through spectral filtering. Pulse duration of... View full abstract»

An equiangular spiral photonic crystal fiber has been designed and numerically optimized to obtain its residual chromatic dispersion compensation property in the wavelength range of 1350-1675 nm. The results show that the fiber exhibits an average dispersion of -227 ps/nm-km with a flattened dispersion profile. It is also demonstrated that the fiber shows a high birefringence of 0.0221 at the wave... View full abstract»

Efficient collection of light into a photonic integrated circuit is becoming increasingly important. To couple light from free-space into an integrated circuit, one needs to efficiently guide it into a photonic wire. By using multiple light capturing elements and tuning their respective phases, it is possible to efficiently guide light into a single-mode waveguide, even when the phase front is dis... View full abstract»

We experimentally characterized the chirp and dispersion tolerance of a single-drive push-pull silicon Mach-Zehnder modulator. The measured data indicate an effective chirp parameter of -0.8 at Vπ drive, which includes contributions from power imbalance, modulation efficiency asymmetry, and inherent free-carrier absorptions. A dispersion tolerance window of 240 ps/nm is de... View full abstract»