Generation Of Optical Systems Research Articles

Off-the-shelf optical systems design enabled by an evolution strategy: front stop case

Commercial off-the-shelf optics enable economic and rapid solutions in the photonics industry and academia. However, the design of optical systems with off-the-shelf optics is a time-consuming task for experienced optical designers and hopeless for novice designers. In this paper, we propose an automatic optical design tool to generate optical systems using only off-the-shelf optical components without human assistance. Our solution is based on an evolution strategy (ES) that performs a discrete combinatorial optimization following optical design-based methodologies that satisfy user-defined specifications. Unlike the conventional methods, the algorithm decreases the design process time and provides optical designers with several optical solutions from where to choose and adapt for targeted applications. In this work, the ES is described and tested with front stop optical configurations. We demonstrate the broad solution domain of the algorithm through the generation of optical systems with F-numbers within a range F/1 to F/90 and field of views up to 300 mm at the image plane. To analyze the solution domain and the characteristics of the solution, we used the design specifications of 29 commercially available scan lenses and compared the performance of different ES parameters. The compatibility of our algorithm with (standard) commercially available optical design software unlocks automatic design tools for off-the-shelf optical systems.

Design and simulation of reconfigurable optical logic gates for integrated optical circuits

The proposed work presents design and simulation of a new reconfigurable optical logic AND, NOT and NOR gate constructed in a two dimensional (2D) photonic crystals (PhCs). Due to many advantages like high speed, fast response, high bit rate and compact size these optical gates find applications in optical devices, communications and optical sensors for next generation optical systems. The proposed gate structures can be used in realization of all optical devices used in photonic integrated optical circuits. These optical logic gates are constructed in 6 µm * 6 µm in 2D PhCs square lattice structure with a lattice constant a = 0.648 µm. All the gates are realized by creating structural disorders in the cross-waveguide geometries of 2D PhCs. The plane wave expansion (PWE) is utilised to get the complete band gap and required band of the waveguide. Finite difference time domain (FDTD) technique is utilised to investigate the performance of these gates. The several performance parameters are examined using this structure and observed that proposed structure has reduced size, fast response time, better contrast ratio against the existing designs and high bit rates of 1.88 Tbit/s and 1.55 Tbit/s for NOT and NOR gates respectively. The amplitude of the optical signal larger than 0.5 arbitrary units (a.u.) and less than 0.1 (a.u.) at output are considered as logic ‘1’ and ‘0’ respectively. The gates are implemented in third optical window at the wavelength of 1.55 µm. RSoft FullWAVE simulator is used to perform simulation.

Towards CW modelocked laser on chip - a large mode area and NLI for stretched pulse mode locking.

Integrated modelocked lasers with high power are of utmost importance for next generation optical systems that can be field-deployable and mass produced. Here we study fully integrated modelocked laser designs that have the potential to generate ultrashort, high power, and high quality pulses. We explore a large mode area laser for high power pulse generation and study the various mode-locking regimes of dispersion managed soliton pulses in net anomalous and net normal dispersion cavities. Furthermore, we study numerically and experimentally general properties and tunability of a fast integrated saturable absorber based on low loss silicon nitride nonlinear interferometer. We believe this work guides the exploration of the future for integrated high power modelocked lasers.

Recent Advances in 100+nm Ultra-Wideband Fiber-Optic Transmission Systems Using Semiconductor Optical Amplifiers

We report on the use of semiconductor optical amplifiers (SOAs) to extend the optical bandwidth of next generation optical systems to 100 nm and beyond. After discussing the technological progress and the motivation for rekindling the interest in SOAs for line amplification, we describe the innovative approach developed for the realization of ultra-wideband (UWB) SOAs. Leveraging custom design of singly polarized SOAs to provide gain over 100+ nm bandwidth, we developed a polarization diversity architecture to realize UWB-SOA modules. Embedded in a compact package, the UWB amplifier modules have been successfully used to demonstrate 100+ Tb/s transmissions. We subsequently review recent experimental transmission results based on such novel 100+ nm wide semiconductor optical amplifiers, including our first demonstration of 100+Tb/s transmission over 100 km distance, our field trial using real-time traffic, and finally the transmission of 107 Tb/s throughput over three spans of standard single mode fiber (SSMF) using hybrid UWB Raman/SOA amplification technique.

Scaling Capacity Growth of Fiber-Optic Transmission Systems Using 100+nm Ultra-Wideband Semiconductor Optical Amplifiers

We report on the use of semiconductor optical amplifiers (SOAs) to extend the optical bandwidth of next generation optical systems. After discussing the technological progress and the motivation for rekindling the interest in SOAs for line amplification, we point out that the nonlinear gain dynamics of SOA is not a limiting factor for employing SOA as line amplifier. We show that the passage to high wavelength division multiplexed (WDM) channel count tends to substantially reduce nonlinear impairments, both through numerical analysis and experimental investigations based on standard off the shelf SOA devices. We then present the characteristics of our novel ultrawideband SOA-based packaged devices exhibiting high gain over 100+nm optical bandwidth, high output saturation power and low noise figure. We finally review the recent demonstration of the first >100+Tb/s transmission based on such novel 100+ nm wide semiconductor optical amplifiers over 100 km distance.

Long-term efficiency preservation for gradient phase metasurface diffraction gratings in the visible

Metal-dielectric metasurfaces with an engineered phase response provide a versatile technology for the next generation of optical systems. However, metal oxidation is detrimental to the performance and lifespan of these devices. Here we demonstrate the design and fabrication of a 1200 lp/mm coated reflective metal-dielectric metasurface grating for use with 650 nm illumination. An 80 nm PMMA coating protects the sample from metal oxidation and sample degradation. The fabricated samples exhibit ~45% efficiency in the first diffractive order over 0-50° angle of incidence consistent with the electromagnetic simulations. The coated samples preserve the performance over 25 weeks in standard room temperature and humidity while the unprotected samples show over an 80% drop in efficiency.

Application of Laser Microscope System for Evaluation of Separation Agents

This paper demonstrates application of laser confocal scanning microscope system for fair-face concrete surface evaluation. Measure system presents a new generation optical system for identification and description of esthetical imperfections of various building materials. System enables 3D observation and high-precision 3D measurement in real time.

Wavelength conversion of 544-Gbit/s dual-carrier PDM-16QAM signal based on the co-polarized dual-pump scheme

Due to its relative low baud rate as well as simple and cost-efficient implementation, dual-carrier polarization-division-multiplexing 16-ary quadrature amplitude modulation (PDM-16QAM) is a promising candidate for the next generation optical systems and networks at 400Gb/s per channel. The co-polarized dual-pump scheme, based on four-wave mixing (FWM) in a 1-km high nonlinear fiber (HNLF), can realize the all-optical wavelength conversion (AOWC) of the dual-carrier PDM-16QAM signal with spectral non-inversion and polarization insensitivity. We first experimentally demonstrated AOWC of the 544-Gbit/s dual-carrier PDM-16QAM signal based on the co-polarized dual-pump scheme. We investigated the conversion efficiency (CE) and optical signal-to-noise ratio (OSNR) of the converted signal at different pump spacing and pump power. We measured that the OSNR penalty is 0.6 dB due to AOWC when the bit-error ratio (BER) and pump spacing is 2 x 10-2 and 200 GHz, respectively.

Influence of “Covercrete” Morphology on Durability Properties

Many leading experts agree on the importance of monitoring the skin as the most loaded area affected by the external environment. Surfacing, concrete mixture composition and curing are of great importance for the concrete surface resistance. The paper introduces an experimental program focused on the monitoring of de-icing salts resistance, depending on surface roughness. Quantitative evaluation of the concrete surface was performed by using confocal laser scanning microscopy, which is the new generation of optical systems that are able to make all measurements in 3D resolution. These measurements are supplemented by results of mechanical and absorption tests.