Photonics Technology Letters, IEEE - new TOC

In Vivo OCT Imaging Using Wavelength-Swept Fiber Laser Based on Dispersion Tuning

June15, 2012

We are developing a wide wavelength-swept fiber laser based on a dispersion tuning method for application to swept-source optical coherence tomography (SS-OCT) imaging. The tuning range of the laser is about 140 nm and the output power is 8 mW on average. We successfully obtained the in vivo OCT picture of the human skin at 1-kHz sweep rate.

Optical Performance Monitoring Using Artificial Neural Networks Trained With Empirical Moments of Asynchronously Sampled Signal Amplitudes

June15, 2012

We propose a low-cost technique for simultaneous and independent optical signal-to-noise ratio (OSNR), chromatic dispersion (CD), and polarization-mode dispersion (PMD) monitoring in 40/56-Gb/s return-to-zero differential quadrature phase-shift keying (RZ-DQPSK) and 40-Gb/s RZ-DPSK systems, using artificial neural networks (ANN) trained with empirical moments of asynchronously sampled signal amplitudes. The proposed technique employs an extremely simple hardware and digital signal processing to enable multi-impairment monitoring at different data rates and for various modulation formats without necessitating hardware changes. Simulation results demonstrate wide dynamic ranges and good monitoring accuracies.

Reconfigurable Four-Input Photonic Logic Minterms and Maxterms Generation Using SOAs

June15, 2012

A generation approach of photonic logic minterms and maxterms, which is fully reconfigured minterms and maxterms for four-input 40-Gb/s differential phase-shift keying (DPSK) signals, has been demonstrated based on delay interferometers and semiconductor optical amplifiers. The maxterms are directly derived by inverting the corresponding minterms, according to their complementary characteristics. Reconfigurations of the scheme, enabled by tuning either the phase shift of delay interferometer or input wavelength, are shown among 16 minterms, as well as corresponding maxterms. A full set of minterms and maxterms are captured with clear open eye diagrams and extinction ratios of over 10 and 8 dB, respectively, which indicate the potential of further realizing arbitrary complex logic operations.

All-Optical xor Gates for QPSK Signals Based on Four-Wave Mixing in a Semiconductor Optical Amplifier

June15, 2012

With the development of transmission systems, all-optical networks need to adapt and process signals utilizing advanced modulation formats. One key element of all-optical networks is all-optical logic gates. Yet few research works on all-optical logic gates are focused on processing such signals. In this letter, all-optical xor gates for optical quadrature phase-shift keying signals are proposed and demonstrated based on four-wave mixing (FWM) in a semiconductor optical amplifier (SOA). Error-free performance is achieved through a 40-GBaud proof-of-concept experiment with an average power penalty of 6 dB. Cross-phase modulation (XPM) effect is found to be the key limiting factor. Given the integration ability of SOA and the format transparency of FWM process, our scheme has potential for future all-optical networks. Yet the XPM effect still needs to be mitigated to achieve better performance in future works.

Wavelength Switchable Semiconductor Laser Based on Half-Wave Coupled Fabry–Pérot and Rectangular Ring Resonators

June15, 2012

A wavelength switchable semiconductor laser based on half-wave coupled Fabry–Pérot and rectangular ring resonators is proposed and demonstrated. The device consists of all-active waveguides to facilitate the fabrication. The cavity lengths are designed with a small difference to employ the Vernier effect to obtain large wavelength tuning. A half-wave coupler is used to produce a phase-dependent loss, thus achieving a high side-mode suppression ratio (SMSR). By adjusting the current applied to just one electrode, six-channels wavelength switching with 200-GHz spacing is measured by the carrier injection effect, with a current variation of only about 20 mA. At higher current injection level, the thermal-optic effect becomes dominant, which produced eight-channels wavelength switching in the opposite direction with a maximal SMSR of 38.5 dB.

Bit-Rate Flexible Demodulation of DPSK Signals Based on Phase Sensitive Gain in Cascaded Four-Wave Mixing

June15, 2012

We demonstrate bit-rate flexible demodulation of differential phase-shift keying (DPSK) signals in a linear structure. The demodulator utilizes a tunable optical delay based on the combination of wavelength conversion in a photonic crystal fiber and dispersion in a short section of single-mode fiber. Error-free demodulations for return-to-zero-DPSK signals at both 25 and 40 Gb/s have been successfully achieved.

Nonuniform Optical Undersampling for High-Resolution Microwave Frequency Measurements

June15, 2012

An optical analog-to-digital converter that uses pulses of multiple wavelengths to nonuniformly sample a microwave signal is used to determine an input microwave frequency to a high accuracy over a large frequency range. Measurement times of 4 μ s lead to frequency errors of ${sim}$ 300 Hz over a measurement range of 10–18 GHz. We also identify the frequency and magnitude of multiple microwave inputs. The simple configuration is robust and practical.

On the Use of Delay-Decorrelated I/Q Test Sequences for QPSK and QAM Signals

June15, 2012

We report on limitations of the commonly used method to generate complex optical signal constellations from delay-decorrelated copies of a bit sequence to modulate in-phase (I) and quadrature (Q) components of a signal constellation. Using closed-form analytical solutions, numerical simulations, and an experimental verification, we show that I/Q delays shorter than the combined channel and adaptive equalizer length can result in artificial improvements of the measured bit-error ratio.

Spatial Resolution Enhancement in Preactivated BOTDA Schemes by Numerical Processing

June15, 2012

A novel processing algorithm is demonstrated for time-domain high-resolution Brillouin schemes based on acoustic field preactivation. An iterative method is employed to correct the measured data from spurious effects associated with acoustic wave transients. Based on a model of the stimulated Brillouin scattering in the frequency domain, the spatial resolution degrading features are computed and subtracted from the acquired data. Experimental tests with 20-cm spatial resolution and dark-pulse pumping are reported.

Measurement Range Elongation Based on Temporal Gating in Brillouin Optical Correlation Domain Distributed Simultaneous Sensing of Strain and Temperature

June15, 2012

We had earlier demonstrated the distributed discrimination of strain and temperature by localizing and scanning both the stimulated Brillouin scattering and the Brillouin dynamic grating along a polarization-maintaining fiber. The localization and scanning were performed by a correlation domain technique, whose measurement range was restricted by the distance between consecutive correlation peaks. To overcome this restriction, in this letter, we apply a temporal gating scheme to the system by enlarging the measurement range from ${sim}{25}$ to ${sim}{500}~{rm m}$. We report the results confirming the effectiveness of this scheme in a system operated by a single laser source, and demonstrate the strain-temperature discrimination when strain or temperature is applied to segments on the 500-m-long fiber under test.

Heteroepitaxy for GaAs on Nanopatterned Si (001)

June15, 2012

An almost defect pit-free GaAs is achieved using nanopatterned Si (001). The largest nanopattern with an aspect ratio of 4.18 and the narrowest strip of around 55 nm in width are adopted in this letter. The threading dislocations, beginning from the GaAs–Si interface and moving along the facet plane to the sidewall, are interrupted within the initial epitaxial layer. With the aspect ratio increasing from 0.44 to 2.04, the etching defect pit density can be decreased from around 5.0$,times 10^{9}~{rm cm}^{-2}$ to almost zero. The improvement in material quality is verified by transmission electron microscopy, photoluminescence, and X-ray diffraction studies.

Proposal of Inverse Pulse Position Modulation for Downstream Signal in Remodulation PON With PolSK-Modulated Multicast Overlay

June15, 2012

Inverse pulse position modulation (PPM) is proposed for downstream data modulation in an optical network unit-source-free wavelength-division-multiplexed passive optical network, while optical amplitude shift keying (ASK) modulation is used for upstream data remodulation. In such a PON, polarization shift keying (PolSK) modulation overlay can be supported on the downstream signals for multicasting services. Our experimental results show that the inverse PPM optical ASK modulation for downstream data has small channel crosstalk with PolSK multicast data and ASK-remodulated upstream data. Compared with the approaches based on the Manchester code or inverse return-to-zero code, the proposed scheme based on inverse PPM has a better power margin, indicating a longer transmission distance and a higher tolerance to link loss.

All-Digital Radio-Frequency Signal Distribution Via Optical Fibers

June15, 2012

We present a radio-frequency (RF) signal distribution system via optical fibers. We utilize an all-digital platform that encompasses a phase-locked loop, numerically-controlled oscillator, and fiber phase noise cancellation system. Our system achieves a fractional frequency transfer stability of 4$,times 10^{-13}$ at 1 s and 6$,times 10^{-17}$ at one day for the distribution of RF signals over 70 km of optical fiber. We demonstrate that this performance can be achieved with standard crystal oscillators. Our system is scalable, configurable, and flexible, allowing distribution of signals at different frequencies while maintaining over two orders of magnitude of the fiber phase noise suppression.

Deep UV ${\rm Ta}_{2}{\rm O}_{5}$ /Zinc-Indium-Tin-Oxide Thin Film Photo-Transistor

June15, 2012

The authors report the fabrication of a deep-ultraviolet sensitive a-ZITO thin-film-transistor (TFT) with a ${rm Ta}_{2}{rm O}_{5}$ gate dielectric. It is found that carrier mobility, threshold voltage, and sub-threshold swing are 106.2 ${rm cm}^{2}/{rm Vs}$, 0.75 V, and 0.45 V/decade, respectively, measured in the dark. It is also found that measured current increased from 2.3$,times 10^{-9}~{rm A}$ to 7.97$,times 10^{-5}~{rm A}$, as we illuminated the sample with $lambda=250hbox{-}{rm nm}$ UV light when ${rm V}_{G}$ is biased at 0 V. Furthermore, it is found that deep-UV-to-visible rejection ratio could reach 2.3$,times 10^{5}$ for the fabricated ${rm Ta}_{2}{rm O}_{5}$/a-ZITO TFT.

Dispersion Characterization of Highly Nonlinear Fiber Over a 700-nm Band

June15, 2012

We demonstrate a new method for wideband dispersion characterization of highly nonlinear fibers with very low dispersion. The new method uses a wideband supercontinuum source and a balanced Mach–Zehnder interferometer architecture. The new dispersion reconstruction algorithm allowed dispersive measurement accuracy of 0.05 ps/km-nm over a 700-nm spectral band for standard (sloped) highly nonlinear fiber.

Coherent Polarization Beam Combining of Four High-Power Fiber Amplifiers Using Single-Frequency Dithering Technique

June15, 2012

We demonstrate a coherent polarization beam combining (CPBC) of four all polarization-maintained high-power fiber amplifiers with a total output power of 60 W, using the single-frequency dithering technique. When the control system is in the closed loop, the intensity profile is steady and the phase noise can be suppressed effectively. The experimental results show that the combining efficiency of the whole system is as high as 90% in the circumstance of imbalance power ratios of the four beams. The technique used in this letter can be straightforwardly scaled to CPBC of a large array of high-power fiber amplifiers.

Wireless Indoor Optical Positioning With a Differential Photosensor

June15, 2012

An indoor optical positioning technique using a differential photosensor device is presented. The method is based on angle of arrival information estimated by the differential photosensor in an indoor environment with fixed optical beacons. A photocurrent is generated by each of the three photodiodes in the photosensor by incident light from the optical beacons. The amplitudes of these photocurrents are a function of the incident angle of the light. Previously derived equations that express photocurrent amplitudes as a function of the azimuthal arrival angle, $phi$ , and the polar arrival angle, $theta$, are modeled with second- and third-order polynomials, respectively, to determine the $phi$ and $theta$ angles from measured photocurrents. Testing with optical beacons in various positions with respect to a fixed photosensor resulted in a root mean squared error for all estimated angles $phi$ and $theta$ of 2.8$^{circ}$. A positioning accuracy of better than 4 cm is achieved.

15-W Fiber-Coupled Quantum-Dot Pump Module

June15, 2012

We have developed 920-nm pump modules for Yb-doped fiber amplifiers. The pump laser utilizes a single layer of In(AlGa)As/GaAs quantum-dot material as active region. Stable operation without thermoelectric cooling, output powers of up to 40 W, and wall-plug efficiencies of more than 50% have been achieved on processed broad-area laser bars. The packaged module reaches 15 W when coupled to a 200-$mu{rm m}$ fiber.

Apodized Silicon-on-Insulator Bragg Gratings

June15, 2012

An accurate control of the apodization profile is still an issue for integrated Bragg grating filters fabricated in silicon-on-insulator because of the high modal confinement of these waveguides. In this letter, we present two fabrication-friendly apodization techniques that are compatible with deep UV lithography and can be used in mass-production of photonic-integrated circuits. These techniques are reliable even for weak effective index modulation amplitude, thus opening the door to the fabrication of long and elaborate grating structures.

Active Plasmonics in True Data Traffic Applications: Thermo-Optic On/Off Gating Using a Silicon-Plasmonic Asymmetric Mach–Zehnder Interferometer

June15, 2012

We present the first system-level demonstration of an active plasmonic device in 10-Gb/s data traffic conditions. An asymmetric silicon-plasmonic Mach–Zehnder interferometer with dielectric-loaded plasmonic waveguides serving as the electrically controlled arms, operates as thermo-optic On/Off gating element with 2.8- µ s response time and 10.8-mW power consumption.

Numerical Study of (0001) Face GaN/InGaN p-i-n Solar Cell With Compositional Grading Configuration

June15, 2012

The advantages of a (0001) face GaN/InGaN p-i-n solar cell with compositional grading configuration between i-InGaN/p-GaN layers are studied numerically. With the use of the grading layer, the conversion efficiency is markedly promoted due to the reduction of potential barrier height for holes and due to the decrease of polarization. Optimized conversion efficiency is obtained when the thickness of the grading layer increases to a critical value. This critical thickness is strongly influenced by the polarization charges and doping concentration of the grading layer. When the density of the polarization charges is high or the doping concentration is low, a thick grading layer is required to achieve high efficiency.

Fast Random Number Generation With Bandwidth-Enhanced Chaotic Semiconductor Lasers at 8 $,\times,$ 50 Gb/s

June15, 2012

We propose a scheme for fast random number generation with bandwidth-enhanced chaotic semiconductor lasers. Chaotic laser intensity output and its time-delayed signal are sampled at 50 GigaSample per second and converted into eight-bit values. The order of the eight-bit samples of the time-delayed signal is reversed, and bitwise exclusive-or operation is executed between the bit-order-reversed samples and the original eight-bit samples. With this method, it is not necessary to eliminate any of the bits in eight-bit samples in order to obtain good-quality random bit sequences. The equivalent generation rate of 8 $,times,$50 Gb/s is achieved in an experiment using bandwidth-enhanced chaotic semiconductor lasers.

Optical-Mode Demultiplexing by Optical MIMO Filtering of Spatial Samples

June15, 2012

An optical spatial-mode demultiplexer is proposed consisting of an optical sampler taking probes from the aperture of the multimode fiber, which are then launched into an optical multiple-input multiple-output (MIMO) filter. A theoretical analysis of coupler matrices of three sampler options reveals that samplers can be characterized by a mode-dependent sampling loss and sampling crosstalk arising from a lacking orthogonality of sampling vectors of different modes. The theoretical optimum MIMO allpass filter can be realized by a waveguide structure consisting of cascaded and in parallel operating directional couplers. The multiplexer is scalable to higher mode numbers due to the absence of splitting loss.

Design of High-Efficiency Fully-Etched Binary Blazed Gratings Nearly Vertical Coupler

June15, 2012

A high-efficiency binary blazed grating nearly vertical coupler with fully-etched spacing is proposed, which can be fabricated in one lithography step integrated with other SOI components. For transverse-electric polarized incident light, the coupling efficiencies from a fiber to waveguide are 59.2% at a wavelength of 1550 nm and 76.9% at 1563 nm, respectively. A 3-dB bandwidth of 33 nm from 1546 to 1579 nm is also obtained. The numerical simulation also shows that the tolerances of 19 nm in etched depth and 6.5$^{circ}$ in incident angle are achievable.

Optically Tunable Frequency-Doubling Brillouin Optoelectronic Oscillator With Carrier Phase-Shifted Double Sideband Modulation

June15, 2012

An optically tunable frequency-doubling optoelectronic oscillator (FD-OEO) based on stimulated Brillouin scattering (SBS) and carrier phase-shifted double sideband (CPS-DSB) modulation is proposed and demonstrated. SBS effect provides narrowband filtering for the OEO to generate an oscillation signal with frequency equal to the Brillouin frequency shift, while a CPS-DSB modulation by using a dual-parallel Mach–Zehnder modulator is implemented to double the oscillation frequency. Owing to the wavelength-dependent Brillouin frequency shift, frequency tunability is realized by tuning the wavelength of the laser source. In the experiments, frequency-doubling microwave signals from 18.38 to 18.74 GHz are generated when the wavelength of the laser source is tuned from 1565 to 1535 nm.

Integrated SU-8 Prisms and Microgratings for Polarization-Selective Fiber-to-Silicon Waveguide Coupling

June15, 2012

A polarization-selective fiber-to-silicon waveguide coupler made by an SU-8 prism as well as a micrograting is demonstrated. The size of the SU-8 prism well matches the core dimension of a single-mode fiber to increase the coupling efficiency, and the micrograting provides the selectivity of polarization mode coupling. Only the TE wave is able to be coupled to the silicon waveguide. The measured coupling loss of the SU-8 prism and the micrograting is 4.5 dB. The polarization extinction ratio is 20 dB. The fiber misalignment tolerances are 2 and 3 µ m for the x- (lateral) and y- (vertical) directions, respectively, according to a transmission window of 3-dB drop.

160-GHz 1.55- $\mu{\rm m}$ Colliding-Pulse Mode-Locked AlGaInAs/InP Laser With High Power and Low Divergence Angle

June15, 2012

A monolithic ${sim}{rm 1.55}hbox{-}mu{rm m}$ colliding-pulse mode-locked AlGaInAs/InP laser with a three-quantum-well active layer incorporating a passive far-field reduction layer has been demonstrated. The device emits pulses at 162 GHz, with a pulsewidth of 0.98 ps, a pulse energy of 0.13 pJ, and a time-bandwidth product of 0.52, while demonstrating a low divergence angle $(12.7^{circ}times 26.3^{circ})$ with a twofold improvement in butt coupling efficiency to a flat cleaved single-mode fiber, compared to the conventional mode-locked lasers.

Highly Sensitive Hydrostatic Pressure Sensing With an Embedded Dual-Polarization Fiber Grating Laser

June15, 2012

In this letter, we propose and demonstrate a highly sensitive hydrostatic-pressure sensor based on a dual-polarization fiber grating laser. The sensor is fabricated by embedding such a laser into a polymer with a steel rod. Due to the significant difference in elastic property, a nonuniform stress field over the package is induced by the applied pressure and an additional intracavity birefringence is produced. The amplitude of the pressure can be measured by monitoring the beat frequency between the orthogonal polarization modes. The sensitivity reaches 0.217 GHz/MPa, 108.5 times higher than that of a bare fiber grating laser. Considering the fluctuation of the beat frequency of ${sim}$0.3 MHz, the resolution of the sensor is about 1.4 kPa, within the range of 0–13 MPa.

Post-Growth Fabrication of Multiple Wavelength DFB Laser Arrays With Precise Wavelength Spacing

June15, 2012

The design and experimental characterization of sidewall-etched gratings in III–V material fabricated with a post-growth technique are presented. The successful demonstration of an array of sidewall-etched distributed feedback lasers shows that this technology allows for a very accurate control of the wavelength spacing and a sidemode suppression ratio up to 60 dB.

Decision-Aided Joint Compensation of Transmitter IQ Mismatch and Phase Noise for Coherent Optical OFDM

June15, 2012

We study the joint effects of transmitter in-phase/quadrature-phase (IQ) mismatch, channel distortion, and laser phase noise in a coherent optical orthogonal frequency-division-multiplexed system. We propose a decision-aided joint compensation scheme, which separates the transmitter IQ mismatch as well as channel distortion and phase noise compensation into two consecutive steps. Simulation results show this novel technique to be effective in mitigating the three effects simultaneously.

Si/Ge Avalanche Photodiodes-Based Electrical Comb-Line Generators and Photoreceivers for Very-Fast Impulse Radio Wireless Linking

June15, 2012

We demonstrate the novel operation of a Si/Ge-based avalanche photodiode (APD) for the direct generation of ultra-wideband (UWB) frequency comb lines for impulse radio (IR) wireless communication. By applying a dc bias $(V_{rm bias})$ over the breakdown voltage $(V_{rm br})$ of the APD, the device can exhibit a significant resonant frequency without any optical signal illumination, and function as an impact ionization avalanche transit time diode-based oscillator. Under an additional electrical intermediate frequency (IF) injection, several frequency comb lines, with a spacing equal to the IF frequency, can be derived from the second harmonic of the oscillating frequency. By mixing the output pulse train from the APD-based UWB generator with the data signal from another Si/Ge APD (on the same chip) operated in the linear mode $(V_{rm bias}, which can perform high-sensitivity optical data detection, error-free IR wireless-linking with data rate as high as 3.0 Gbit/s has been successfully achieved.

High Bit Rate Fiber-Optic Transmission Using a Four-Chaotic-Semiconductor-Laser Scheme

June15, 2012

Successful high-speed fiber-optic transmission using a four-chaotic-semiconductor-laser system is numerically demonstrated. The system performance is benefited from the properties of bandwidth enhancement and the implementation of a two-channel scheme. The bit-error rate of the recovered message is evaluated for different fiber lengths and message bit rates, respectively. In particular, acceptable communication performance can be achieved for a bit rate up to 8 Gb/s when the fiber length is approximately 60 km. Such a system could lead to high-speed chaos-based encryption/decryption even if the fiber transmission module is considered.

Photonics Technology Letters, IEEE - new TOC

In Vivo OCT Imaging Using Wavelength-Swept Fiber Laser Based on Dispersion Tuning

Optical Performance Monitoring Using Artificial Neural Networks Trained With Empirical Moments of Asynchronously Sampled Signal Amplitudes

Reconfigurable Four-Input Photonic Logic Minterms and Maxterms Generation Using SOAs

All-Optical xor Gates for QPSK Signals Based on Four-Wave Mixing in a Semiconductor Optical Amplifier

Wavelength Switchable Semiconductor Laser Based on Half-Wave Coupled Fabry–Pérot and Rectangular Ring Resonators

Bit-Rate Flexible Demodulation of DPSK Signals Based on Phase Sensitive Gain in Cascaded Four-Wave Mixing

Nonuniform Optical Undersampling for High-Resolution Microwave Frequency Measurements

On the Use of Delay-Decorrelated I/Q Test Sequences for QPSK and QAM Signals

Spatial Resolution Enhancement in Preactivated BOTDA Schemes by Numerical Processing

Measurement Range Elongation Based on Temporal Gating in Brillouin Optical Correlation Domain Distributed Simultaneous Sensing of Strain and Temperature

Heteroepitaxy for GaAs on Nanopatterned Si (001)

Proposal of Inverse Pulse Position Modulation for Downstream Signal in Remodulation PON With PolSK-Modulated Multicast Overlay

All-Digital Radio-Frequency Signal Distribution Via Optical Fibers

Deep UV /Zinc-Indium-Tin-Oxide Thin Film Photo-Transistor

Dispersion Characterization of Highly Nonlinear Fiber Over a 700-nm Band

Coherent Polarization Beam Combining of Four High-Power Fiber Amplifiers Using Single-Frequency Dithering Technique

Wireless Indoor Optical Positioning With a Differential Photosensor

15-W Fiber-Coupled Quantum-Dot Pump Module

Apodized Silicon-on-Insulator Bragg Gratings

Active Plasmonics in True Data Traffic Applications: Thermo-Optic On/Off Gating Using a Silicon-Plasmonic Asymmetric Mach–Zehnder Interferometer

Numerical Study of (0001) Face GaN/InGaN p-i-n Solar Cell With Compositional Grading Configuration

Fast Random Number Generation With Bandwidth-Enhanced Chaotic Semiconductor Lasers at 8 50 Gb/s

Optical-Mode Demultiplexing by Optical MIMO Filtering of Spatial Samples

Design of High-Efficiency Fully-Etched Binary Blazed Gratings Nearly Vertical Coupler

Optically Tunable Frequency-Doubling Brillouin Optoelectronic Oscillator With Carrier Phase-Shifted Double Sideband Modulation

Integrated SU-8 Prisms and Microgratings for Polarization-Selective Fiber-to-Silicon Waveguide Coupling

160-GHz 1.55- Colliding-Pulse Mode-Locked AlGaInAs/InP Laser With High Power and Low Divergence Angle

Highly Sensitive Hydrostatic Pressure Sensing With an Embedded Dual-Polarization Fiber Grating Laser

Post-Growth Fabrication of Multiple Wavelength DFB Laser Arrays With Precise Wavelength Spacing

Decision-Aided Joint Compensation of Transmitter IQ Mismatch and Phase Noise for Coherent Optical OFDM

Si/Ge Avalanche Photodiodes-Based Electrical Comb-Line Generators and Photoreceivers for Very-Fast Impulse Radio Wireless Linking

High Bit Rate Fiber-Optic Transmission Using a Four-Chaotic-Semiconductor-Laser Scheme

Deep UV ${\rm Ta}_{2}{\rm O}_{5}$ /Zinc-Indium-Tin-Oxide Thin Film Photo-Transistor

Fast Random Number Generation With Bandwidth-Enhanced Chaotic Semiconductor Lasers at 8 $,\times,$ 50 Gb/s

160-GHz 1.55- $\mu{\rm m}$ Colliding-Pulse Mode-Locked AlGaInAs/InP Laser With High Power and Low Divergence Angle