This PDF file contains the front matter associated with SPIE Proceedings Volume 8781 including the Title Page, Copyright information, Table of Contents, Introduction, and Conference Committee listing.

Silicon photonics is maturing rapidly on a technology basis, but design challenges are still prevalent. We discuss these challenges and explain how design of photonic integrated circuits needs to be handled on both the circuit as on the physical level. We also present a number of tools based on the IPKISS design framework.

An understanding of parasitic effects is essential to maximize the performance of a Photonic Integrated Circuit (PIC). Using a circuit simulator, we are able to model mode conversion at the interface between straight and bent waveguides, parasitic reflections in multi-mode interference couplers (MMIs), interference between multiple modes, residual facet reflections, and reflections at junctions between components. Even though these effects are usually low in intensity, around -20 dB to -30 dB from the main signal level, they can still have a strong influence on the circuit performance. This is because the mentioned parasitic effects are coherent with the desired signal and interference between them is therefore a field effect. By analyzing three different circuits, and comparing the results to measurements, we show that these effects need to be carefully managed in order to ensure circuit performance. The circuits we investigate are a Fabry-Perot cavity, a Mach- Zehnder interferometric structure, and a Michelson interferometer. Especially residual reflections coming from angled facets and back-reflections in MMIs are shown to be the main parasitic effects in the investigated circuits.

We perform the thermal and optical simulations of silicon nitride / polymer hybrid waveguides with different heating schemes by finite element method. Both the top and buried microheaters are adopted to realize tuning function by the thermo-optic effect. We find the buried microheater is more energy-efficient than the top microheater in creating a uniformed temperature environment in the waveguide region. On the other hand, the top electrode tends to create a strong temperature gradient through the waveguide, which in turn distorts the optical mode. This distortion, however, is different for TE and TM modes. This thermally induced birefringence effect is thoroughly investigated in this paper.

Paper present results of numerical investigation by finite difference time domain (FDTD) method of new tunable optical filter which utilized multiple coupled silicon wire waveguides on SOI structures. In order to improve simulation accuracy we introduce modified effective index method (MEIM) which correctly describes in 2d case both the phase and the group indexes in 3d strip waveguide, typically used in silicon photonics in thin SOI structures. MEIM utilizes the combined index profile containing two spatial parameters as in actual 3d waveguide. Namely, the central part with refractive index of Si has the width w around waveguide height h and it is mainly responsible for the group index. The base part has the same width W as in 3d waveguide and refractive index Nb which is mainly responsible for the phase index. As a results, MEIM provides typical error about 1%-2% for the filter free spectral range (FSR) instead of about 30% for EIM. Numerical simulation of novel filter proves its general conception and demonstrates that a short 360 mkm structure with 32 couplers has spectral resolutions 1.5 nm, loss -1 dB and sidelobes below -26 dB. It provides wavelength tuning (without Vernier principle) within total FSR 36 nm at central optical wavelength 1.55 mkm by temperature change up to 100 C in four sets of thermo optic phase shifters. Device of 1 cm size provides 0.05 nm filter linewidth. Filter can be manufactured by CMOS compatible technology and very promising for applications in photonics.

Silicon photonics has emerged as a promising material system for the fabrication of photonic devices as well as electronic ones. The key advantage is that many electronic and photonic functions that up to now have only been available as discrete components can be integrated into a single package. We present a silicon photonic platform that includes low-loss passive components as well as high-speed modulators and photodetectors at or above 30 GHz. The platform is available to the community as part of the OpSIS-IME MPW service.

Integrated polarization rotators suffer from very high sensitivity to fabrication errors. A polarization rotator scheme that substantially increases fabrication tolerances is proposed. In the proposed scheme, two tunable polarization phase shifters are used to connect three rotator waveguide sections. By means of properly setting the polarization phase shifters, fabrication errors are compensated and perfect polarization rotation is achieved. Analytical conditions are shown that determine the maximum deviation that can be corrected with the proposed scheme. A design example is discussed, where the thermo-optic effect is used to provide the required tunable polarization phase shifting. Calculated 40dB extinction ratio is shown in presence of fabrication errors that would yield a 4dB extinction ratio in the conventional approach.

Small-radius microring resonator with large free spectral range (FSR) are of great interest for optical communication and optical interconnect applications. Multi-ring structures are used to generate a box-like spectrum with large FSR. However, coupling coefficient in conventional ring resonator structure is not large enough. In this paper, we design a novel conformal race-track structure to enlarge the interaction region between bus waveguide and microring, which can effectively enhance the coupling coefficient. The simulated results show that the power coupling coefficient of the conformal race-track structure with a conformal angle of 80° is around 9.32%, which is quite large for the criterion of multi-ring structure, so that we can design a box-like and narrow passband with large FSR .

Subwavelength grating (SWG) waveguides offer the freedom of (effective) refractive index variation in the design of integrated optical components and devices in silicon-on-insulator waveguides without significantly increasing fabrication complexity. An SWG waveguide is formed by a subwavelength (quasi)-periodic structure consisting of short segments of silicon embedded into a lower-index superstrate. As a result, to the first approximation, the SWG waveguide behaves as a channel waveguide with its core refractive index determined by the filling factor of silicon in the superstrate. By changing the filling factor, i.e., the duty-cycle of the SWG structure, its (effective) refractive index can be varied essentially between that of the superstrate and that of silicon. Here we present a numerical analysis of light coupling between a conventional silicon nanowire waveguide and a periodic SWG waveguide by means of a tapered SWG coupler. The coupler function is to facilitate the smooth and low-loss transition from a conventional mode of a photonic nanowire to a Bloch mode of a periodic SWG waveguide, both propagating with different group velocities. To increase the reliability of numerical simulations, two independent 3D numerical codes based on different formulations of a Fourier modal method (FMM) are used for the analysis. Results of modeling of tapered SWG couplers of different lengths confirm excellent optical properties of these couplers, including very low coupling and return losses.

In new designs permitted by heteroepitaxial bonding of III-V active slabs onto nano-patterened SoI wafers, two constraints arise in the design: optical confinement and thermal performance. One require less silicon for the former and more silicon for the latter. We propose a mitigation strategy based on electromagnetism and a flip-flop algorithm.

A cost-effective solution to provide higher data rates in wireless communication system is to push carrier wave frequencies into millimeter wave (MMW) range, where the frequency bands within the E-band and F-band have been allocated. Photonics is a key technology to generate low phase noise signals, offering methods of generating continuous MMW with varying performance in terms of frequency bandwidth, tunability, and stability. Recently, we demonstrated for the first time of our knowledge the generation of a 95-GHz signal by optical heterodyning of two modes from different channels of a monolithically integrated arrayed waveguide grating multi-wavelength laser (AWGL). The device uses an arrayed waveguide grating (AWG) as an intra-cavity filter. With up to 16-channel sources with independent amplifiers and a booster amplifier on the common waveguide, the laser cavity is formed between cleaved facets of the chip. The two wavelengths required for optical heterodyning are generated activating simultaneously two channel SOAs and the Boost amplifier. In this work, we analyze the effect on the dual-wavelength operation of the Boost SOA, which is shared by two wavelengths. Mapping the optical spectrum, sweeping the two channel and Boost bias currents, we show the interaction among the different SOAs two find the regions of dual wavelength operation. The size of dual wavelength operation region depends greatly on the Boost SOA bias level. Initial results of a numerical model of the AWGL will be also presented, in which a digital filter is used to implement the AWG frequency behavior.

The most cost-effective solution for modulating data onto an optical carrier is via direct modulation of a semiconductor laser. Unfortunately, this approach suffers from high chirp. The chirp can be reduced by reducing the on/off modulation contrast ratio (i.e. by keeping the signaling laser well above threshold when generating both logical ‘0’ and ‘1’ bits), but the low contrast ratio itself compromises performance. Other techniques can better suppress chirp, e,g., based on selfinjection or optical injection locking of the directly-modulated laser (slave) to another laser (master) that emits CW light. However, this technique although very efficient at eliminating chirp, also requires the slave laser be operated well above threshold. We show however that the issue of the limited on/off modulation contrast can be addressed in this instance by subtraction of the carrier using a component of the master beam and an interferometric arrangement.

Optical injection locking can be used to isolate and amplify individual comb modes from an optical frequency comb (OFC). However, it has been observed that for narrow spaced OFCs (e.g. 250 MHz), the adjacent comb modes are still present in the output of the locked laser. These residual modes experience some amplification relative to the injected signal, however the gain is significantly less than for the locked mode. We report the measurement of this sidemode amplification for a semiconductor laser injection locked to a 250 MHz spaced OFC. It was found that this amplification can be well suppressed by tuning the frequency difference between the free running laser and the OFC mode it was locked to. The sidemode amplification was then investigated numerically by solving the laser rate equations under optical injection. It was found that the main contribution to the sidemode amplification was due to phase modulation induced by the residual comb modes. The detuning dependent suppression occurs due to destructive interference between pairs of equidistant comb modes.

We report on the observation of superlinear electroluminescence in nanoheterostructures based on GaSb with a deep narrow Al(As)Sb/InAsSb/Al(As)Sb quantum well in the active region, grown by metal organic vapor phase epitaxy. Electroluminescence spectra for different driving currents were measured at temperatures of 77 and 300 K. It is shown that such structure exhibits superlinear dependence of optical power on the drive current and its increase of 2-3 times in the current range 50-200 mA. This occurs due to impact ionization in the Al(As)Sb/InAsSb quantum well in which a large band offset at the interface ΔE_C = 1.27 eV exceeds ionization threshold energy for electrons in the narrow-gap well. Theoretical calculation of the size quantization energy levels is presented, and possible cases of impact ionization, depending on the band offset ΔE_C at the interface and on the quantum well width, are considered. This effect can be used to increase quantum efficiency and optical power of light emitting devices (LEDs, lasers) operating in mid-infrared spectral range, as well as for photovoltaic elements.

We report the fabrication and characterisation of near perfect ultra-long fibre Bragg gratings for applications in signal processing. Narrow bandwidth down to ~few pm FWHM have fabricated using an electro-optic modulation technique, and characterised for their transfer functions and dispersion. Near perfect characteristics have been achieved with symmetric group-delay and transmission spectra. 30cm-long, ultra-high reflectivity gratings are also reported. We discuss prospects for making complex gratings with very low residual noise, opening unprecedented possiblities for signal processing in the RF, microwave and the THZ regions.

In this paper we report a new set of accurate measurements of guided mode resonances coupled in a negative photonic crystal slab. Narrow peaks are visible in the reflection spectrum with a full-width at half maximum (FWHM) of less than 2 nm. In addition to the traditional measurements of the reflected signal, we present the imaging of the coupled radiation propagating into the slab. Finally, by comparison with the already known phenomenological analysis [1] we propose a new physical model of the phenomenon. The experimental data shows an excellent agreement with mentioned theory.

This paper describes the parallel computational approach for the analysis of the multiple scattering of light from a three dimensional ensemble of many spherical particles having an ordered face-centered cubic lattice structure. The solution is obtained by numerically solving the Maxwell's equations using the FDTD (Finite Difference Time Domain) method with an impinging electromagnetic plane. The aim is to simulate the reflectance and transmittance of the system in the 300÷700 nm wavelength range, calculating also the angular power distribution of the scattered light. This study is suitable for the optical characterization of opal photonic crystals.

Development in photonics for communications and interconnects pose increasing requirements on reduction of footprint, power dissipation and cost, as well as increased bandwidth. Nanophotonics integrated photonics has been viewed as a solution to this, capitalizing on development in nanotechnology and an increased understanding of light matter interaction on the nanoscale. The latter can be exemplified by plasmonics and low dimensional semiconductors such as quantum dots (QDs). In this scenario the development of improved electrooptic materials is of great importance, the electrooptic polymers being an example, since they potentially offer superior properties for optical phase modulators in terms of power and integratability. Phase modulators are essential for e.g. the rapidly developing advanced modulation formats, since phase modulation basically can generate any type of modulation. The electrooptic polymers, in combination with plasmonics nanoparticle array waveguides or nanostructured hybrid plasmonic media can give extremely compact and low power dissipation modulators. Low-dimensional semiconductors, e.g. in the shape of QDs, can be employed for modulation or switching functions, offering possibilities for scaling to 2 or 3 dimensions for advanced switching functions. In both the high field confinement plasmonics and QDs, the nanosizing is due to nearfield interactions, albeit being of different physical origin in the two cases. Epitaxial integration of III-V structures on Si plays an important role in developing high-performance light sources on silicon, eventually integrated with silicon electronics. A brief remark on all-optical vs. electronically controlled optical switching systems is also given.

The energy consumption per transmitted bit is becoming a crucial figure of merit for communication channels. In this paper, we study the design trade-offs in photodetectors, utilizing the energy per bit as a benchmark. We propose a generic model for a photodetector that takes optical and electrical properties into account. Using our formalism, we show how the parasitic capacitance of photodetectors can drastically alter the parameter values that lead to the optimal design. Given certain energy-per-bit and bandwidth requirements, is it possible that a photodetector optimized for the energy per bit would be noise limited? We identify different noise sources and model them in the simplest useful approximation in order to calculate this noise limit. Finally, we apply our theory to a practical case study for an integrated plasmonic photodetector, showing that energies per bit below 100 attojoules are feasible despite metallic losses and within noise limitations without the introduction of an optical cavity or voltage amplifying receiver circuits.

Plasmonic lenses (PLs) are based on complex combination of various width nanoscale and high aspect ratio slits. We investigate a more simplified design keeping similar performances while releasing technological constraints. This simplification is based on an energetic analysis of the contribution of each slit relative to the entire PLs behaviour. We demonstrate that a simplified plasmonic lens (SPL) can be designed which has the same behaviours as PLs.

Active research into nanoscience and nanotechnologies that are available for nano fabrication have lead to considerable progress in the understanding of the optical properties of metals on nanometer scale. Here, noble-metal strip-like nanostructures are attractive objects of research. Indeed, they can be easily manufactured and serve as building blocks of optical nanoantennas and sensors with unique geometry-dependent optical properties. This is because they display intensive localized surface-plasmon resonances in the visible and far-infrared ranges that lead to near- and far-field enhancement effects. Thanks to surface-plasmon resonances, multi-element finite gratings have attractive properties of extraordinarily large reflection, absorption, and transmission, depending on the arrangement of the elementary cell of the grating. All these phenomena are greatly influenced by the so-called grating resonances which appear due to periodicity. The 2D modeling of electromagnetic wave scattering by thin noble-metal nanosize strips and their finite-periodical ensembles arranged in comb-like gratings is considered. Our analysis is carried out using new efficient, convergent and accurate method. It is based, first, on the use of the generalized boundary conditions (GBC) valid for a thin and highcontrast material layer; they allow us to consider only the limit values of the field components and reduce integration contour to the collection of corresponding strip median lines. Second, for the building of discrete model of the obtained singular integral equations, we use very efficient Nystrom-type algorithm with quadrature formulas of interpolation type. We study the SPRs of the finite periodic comb-like strip ensembles versus the incidence angle of the plane electromagnetic wave and the strip characteristics; both near-field and far-field properties of the associated surfaceplasmon resonances and especially local field enhancements or focusing effects are analyzed. Moreover, we investigate the periodicity-induced properties such as the grating resonances in the context of the development of optimal design strategies for efficient multi-strip optical nanoantennas

We have investigated several material platforms for the mid-infrared including silicon on insulator (SOI), polycrystalline silicon, and suspended silicon structures. We review photonic devices based on these platforms including splitters, ring/racetrack resonators, Mach-Zehnder interferometers, and spectrometers.

Silicon nitride (SiN) is a promising candidate material for becoming a standard high-performance solution for integrated biophotonics applications in the visible spectrum. As a key feature, its compatibility with the complementary-oxidemetal- semiconductor (CMOS) technology permits cost reduction at large manufacturing volumes that is particularly advantageous for manufacturing consumables. In this work, we show that the back-end deposition of a thin SiN film enables the large light-cladding interaction desirable for biosensing applications while the refractive index contrast of the technology (Δn ≈ 0.5) also enables a considerable level of integration with reduced waveguide bend radii. Design and experimental validation also show that several advantages are derived from the moderate SiN/SiO₂ refractive index contrast, such as lower scattering losses in interconnection waveguides and relaxed tolerances to fabrication imperfections as compared to higher refractive index contrast material systems. As a drawback, a moderate refractive index contrast also makes the implementation of compact grating couplers more challenging, due to the fact that only a relatively weak scattering strength can be achieved. Thereby, the beam diffracted by the grating tends to be rather large and consequently exhibit stringent angular alignment tolerances. Here, we experimentally demonstrate how a proper design of the bottom and top cladding oxide thicknesses allows reduction of the full-width at half maximum (FWHM) and alleviates this problem. Additionally, the inclusion of a CMOS-compatible AlCu/TiN bottom reflector further decreases the FWHM and increases the coupling efficiency. Finally, we show that focusing grating designs greatly reduce the device footprint without penalizing the device metrics.

In this paper, we present our theoretical and experimental work on hybrid plasmonic microdisks. The 170 nm wide access waveguide is first simulated and characterized, and shows a propagation loss about 0.08 dB/μm. 3-D FDTD simulations are then used to investigate the lower limit of the bending radius of the hybrid plasmonic microdisk. Microdisks with radius around 500 nm are fabricated, characterized, and analyzed. The 5th and 4th order resonances are experimentally observed around 1412 nm and 1625 nm. The extinction ratios of the two resonances are measured to be 5.5dB and above 10dB, respectively. The measured intrinsic quality factors are 350 and 110, respectively. Comparisons are also made between the theoretical and experimental results. The demonstrated ultra-small hybrid plasmonic microdisk may find applications in low-power-consumption modulators, nano laser cavities with large Purcell-factor, molecule sensors, and others.

We report different experimental results showing the large potential of Ge/SiGe quantum well structures as a promising solution forlow power consumption and large bandwidth optical modulators in silicon photonics technology. First, high speed operation of such a Ge/SiGe multiple quantum well (MQW) electro-absorption modulator is reported, with 23 GHz bandwidth demonstrated from a 3 μm wide and 90 μm long Ge/SiGe MQW waveguide. Then the flexibility to shift the absorption band edge from 1.42 to 1.3 μm is illustrated by strain engineering of the Ge wells. Finally electrorefraction by Quantum Confined Stark Effect (QCSE) is demonstrated, opening the route towards phase modulators based on Ge/SiGe MQWs.

Optimizing the properties of optical and photonic devices calls for the need to control and manipulate light within structures of different length scales, ranging from sub-wavelength to macroscopic dimensions. Working at different length scales, however, requires different simulation approaches, which have to account properly for various effects such as polarization, interference, or diffraction: at dimensions much larger than the wavelength of light common ray-tracing techniques are conveniently employed, while in the (sub-)wavelength regime more sophisticated approaches, like the socalled finite-difference time-domain (FDTD) technique, are used. Describing light propagation both in the (sub-)wavelength regime as well as on macroscopic length scales can only be achieved by bridging between these two approaches. Unfortunately, there are no well-defined criteria for a switching from one method to the other, and the development of appropriate selection criteria is a major issue to avoid a summation of errors. Moreover, since the output parameters of one simulation method provide the input parameters for the other one, they have to be chosen carefully to ensure mathematical and physical consistency. In this contribution we present an approach to combine classical ray-tracing with FDTD simulations. This enables a joint simulation of both, the macro- and the microscale which refer either to the incoherent or the coherent effects, respectively. By means of an example containing one diffractive optical element (DOE) and macroscopic elements we will show the basic principles of this approach and the simulation criteria. In order to prove the physical correctness of our simulation approach, the simulation results will be compared with real measurements of the simulated device. In addition, we will discuss the creation of models in FDTD based on different analyze techniques to determine the dimensions of the DOE, as well as the impact of deviations between these different FDTD models on the simulation results.

We study truncated Airy pulses launched into an anomalous dispersion domain of a fiber with strong positive third order dispersion. The pulse quickly reaches the focal point, and then it undergoes a mirror transformation and continues to propagate with the acceleration in the opposite direction. At the focal point all of the light pulse energy is concentrated in a very narrow temporal slot, exhibiting an intriguing pulse compression technique. When both dispersion terms act on the pulse, the focal point extends to a finite area of spreading of the truncated Airy pulse. The size of the area depends on the relative strength of the TOD term relative to its second-order counterpart. After this area, the pulse reemerges again and continues its evolution mirror-transformed. A full exact analytical description of pulses dynamics is developed and verified with direct numerical simulations.

The conception of excellent waveguide crossing by making the optical beam to pass over the intersecting silicon wire waveguide is numerically investigated in the paper. It is realized by means of vertical up and down coupling through the silica buffer of tapered Si wires with the upper polymer strip waveguide constructed by SU-8 (with refractive index 1.56). For the case of silicon wire with height 220 nm and width 450 nm the following parameters are used in the optimal structure: the silica buffer - 180 nm, the taper length and tip - 30 mkm and 160 nm, SU-8 polymer height and width - 1.7 mkm and 1.5 mkm, respectively. At the central optical wavelength of 1.55 mkm it provides the total loss about 0.1 dB for the through path: silicon wire – upper polymer – silicon wire. Thus, it provides the possibility for several silicon wire crossings at a moderate loss. For the cross pass direction the optical wave passes through the straight silicon waveguide and senses the present of the crossing waveguides only by the evanescent field. Thus, it provides negligible losses and the possibility for multi-hundreds waveguide crossings. In order to study the task of light propagation through the multiple crossings we use the modified method of lines and the effective index method approximation. Our results were tested by the numerical experiments by 3D finite difference time domain (FDTD) method. The simulations prove that the proposed structure provides almost a lossless silicon wire crossing (<0.002 dB) which can find multiple applications in photonics for the cases when effective multiple crossings are needed.

Two optical methods are used in the laser-based experiment OSQAR at CERN for the search of axions and axion-like particles. The first method looks as light shining through the wall. The second one wants to measure the ultra-fine vacuum magnetic birefringence. Both methods have reached its attainable limits of sensitivity. Present work is focused on increasing the number of photons and their endurance time within the magnetic field using a laser cavity. Presented paper covers recent state of development of a prototype of a 1 meter long laser cavity which is the prerequisite of further development of the experiment.

We observed high quality elastic light scattering from a silicon microsphere in the standard telecommunication band. A tunable diode laser was used as the excitation source and a single mode silica optical fiber setup delivered the input laser light to the microsphere. The silicon microsphere was manipulated on the silica optical fiber half coupler (OFHC) to effectively couple the evanescent laser field to the microsphere thus exciting the whispering gallery modes (WGM’s). We observed high quality factor WGM’s which can lead to novel geometries and applications for silicon microsphere based optoelectronic devices, such as filters, modulators, and detectors.

In this work, an exact numerical analysis has been made for rate equations of continuous-wave (CW) cladding-pumped fiber amplifier. A comprehensive form is considered including the pump coupling efficiency, splice points and scattering losses. Moreover, we have focused on determination of the small-signal gain and the saturation power for a typical single-stage large-mode area (LMA) Yb-doped silica fiber amplifier based on the steady-state amplification relation. The dependency of those parameters to the pump power is investigated which is significantly due to the signal power filling factor.

With the recent development of less costly uncooled detectors technology, expensive optics are among the remaining significant cost drivers. As a potential solution to this problem, the fabrication of IR lenses using chalcogenide glasses has been studied in recent years. We report on fabrication of molded chalcogenide-glass lens for car night-vision and on the evaluation of the lens. The moldability of chalcogenide glass was characterized through transcription properties of the mold’s surface. In addition, both IR transmittance and XRD patterns of the molded chalcogenide glass lens were evaluated to verify the compositional and structural stability of the glass material at the corresponding molding condition.

In this work, an exact numerical analysis of an end-pumped continuous-wave (CW) double-clad fiber laser with linearcavity design has been intensively carried out based on a set of propagation rate equations including loss coefficients. Following the theoretical analysis of the rate equations describing pump coupling, fiber end-face cleaving (air reflection), splice points, combiner, fiber Bragg gratings (FBGs) and scattering losses, a comparison has also been made between the numerical predictions and the experimental results due to a typical single-mode ytterbium (Yb)-doped silica rectilinear fiber laser.

High-power, single longitudinal mode, single-polarization beam generates from a polarization maintaining double-clad Yb-doped silica fiber laser is more applicable for inertial confinement fusion (ICF) applications. The laser beamlets that converge on a target originate from a low power fiber laser in the master oscillator room (MOR). The laser seed signal amplifies through several cascaded amplifier chains in the front-end system. Today, the most famous fusion facilities, including National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL), Ligne d’Intégration Laser- Laser Mégajoule (LIL-LMJ) and OMEGA utilize fiber-based lasers. In this paper, we have compared various pumping modes comprising end-pumped master oscillator-power amplifier (MOPA) configuration and distributed sidepumped multifiber series fiber laser for scaling up the power of large-mode area (LMA) Yb:silica fiber laser for forward pumping regime.

Silicon nitride ring resonators with diameter of 250 and 500 μm are fabricated and their spectral characteristics investigated with the ultimate goal of optical frequency comb generation for astronomical spectrograph calibration. A continuously tunable laser was used to evaluate the spectral characteristics (propagation losses and transmission properties) of PECVD silicon nitride waveguides and ring-resonators. Losses were measured to be smaller than 0.75 dB/cm over the range between 1500 nm and 1620 nm. The transmission properties of the fabricated ring resonators were assessed for the TE and TM modes, showing promise for the ultimate goal of astronomical optical frequency comb generation.

The engineering of the propagation constant in integrated silicon nitride waveguides is numerically investigated. We compare several geometrical designs and show that fairly large chromatic dispersion control is obtained when the transversal dimensions are modified.

The one-dimensional aperiodic structure is considered which is formed by stacking together chiral and achiral layers according to the Kolakoski self-generation scheme. Numerical simulations are carried out for different structure configurations to reveal the dependence of the optical characteristics of the system on the generation stage, frequency, chirality parameter, and the angle of wave incidence.

In this paper we propose an approach based on the Dynamical Diffraction Theory (DDT) is presented in order to derive an analytic formulation of superprism effect that exhibit an extremely high angular dispersion. We apply the theory to a one dimensional Photonic Crystal (1D-PhC) at the wavelength of 1.55μm. We demonstrate that it is possible to obtain an angular dispersion of 9.73°/nm by using a structure of Si/SiGe, which represent among the higher dispersion available in literature.

In this paper, we compare the performance of Polarization Multiplexing-Differential Quadrature Phase Shift Keying (POLMUX-DQPSK) and Dual Carrier-Differential Quadrature Phase Shift Keying (DC-DQPSK) with RZ (Return-to- Zero) carving and duty cycle of 33% in 100 Gb/s transmission systems. These formats appear to be the most promising technology for long-haul with coherent detection. POLMUX-DQPSK use the polarization dimension of the optical signal to transmit the information. DC-DQPSK uses two wavelengths to transmit the information. We discuss their back-toback receiver sensitivity and required Optical-to-Noise Signal Ratio (OSNR) for a Bit Error Rate (BER) equal to 10^-9. We find that 33RZ-POLMUX-DQPSK has the best receiver sensitivity and lower OSNR penalty compared to 33RZ-DCDQPSK. For 33RZ-POLMUX-DQPSK sensitivity as reference, we can observe a benefit of 1.5 dB for 33RZ-DCDQPSK. Also, we can observe a benefit of 2.3 dB in OSNR for 33RZ-POLMUX-DQPSK compared to 33RZ-DCDQPSK. We study the robustness of these two optical modulation formats for transmission of 1.6 Tb/s (16×100 Gb/s) over 1200 km in dispersion compensated Wavelength Division Multiplexing (WDM) systems with 100 GHz channel spacing using two types of fibers Standard Single Mode Fiber (SSMF) and Non-Zero Dispersion Shifted Fiber (NZDSF). We find that 33RZ-DC-DQPSK is a suitable modulation formats in dispersion compensated WDM systems with 100 Gb/s channel spacing using NZDSF fiber. We simulate the nonlinear tolerance of optical 33RZ-POLMUX-DQPSK and 33RZ-DC-DQPSK formats. 33RZ-DC-DQPSK modulation format has the best robustness against the nonlinear fiber effects in NZDSF fiber.