Beam forming optic aberrations’ impact on maximum range of semiconductor laser based rangefinders

2014 ◽  
Vol 22 (3) ◽  
Author(s):  
J. Wojtanowski ◽  
M. Zygmunt ◽  
M. Traczyk ◽  
Z. Mierczyk ◽  
M. Jakubaszek
Keyword(s):  
Semiconductor Laser ◽  
Signal To Noise Ratio ◽  
Beam Forming ◽  
Substantial Part ◽  
Optical Fabrication ◽  
Optical Aberrations ◽  
Optical Components ◽  
Current Trends ◽  
Maximum Range ◽  
Measurable Range

AbstractMiniature rangefinding modules based on pulsed semiconductor laser technology are becoming more and more popular components of a variety of modern optoelectronics devices where precise, fast and eye-safe range estimation is needed. Current trends associated with minimization of both physical dimensions and cost of such modules lead to the design approach relying on exact meeting the requirements of a given application, concerning the spatial resolution and especially the maximum range. Optical components of a rangefinder cover a substantial part of its cost and determine its overall dimensions, but primarily — the indigenous parameters of the transmitter and receiver trains are crucial for the maximum measurable range. The quantitative analysis of transmitter optics aberrational characteristics impact on signal-to-noise ratio range dependence and thus the maximum range of a laser rangefinder is presented in the paper. Modern optical fabrication technology offers a huge range of solutions, changing in imaging/projecting characteristics which implies the price level as well. Rangefinder optics has a very specific task which sometimes makes it unreasonable to fight for the diffraction limited performance. The article provides the approach how to determine the acceptable level of optical aberrations which still does not degrade the measurable range significantly.

A critical review of optical switches

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ompal Singh ◽  
Rajeev Paulus
Keyword(s):  
Future Generation ◽  
Optical Switches ◽  
Literature Survey ◽  
Optical Packet Switching ◽  
Optical Fabrication ◽  
Optical Components ◽  
Detailed Review ◽  
Switch Architectures ◽  
Packet Switch ◽  
Large Speed

Abstract Optical packet switching has gained lot of popularity in last a few years due to its advantages like, large speed, more bandwidth and very less crosstalk. But due to immature optical fabrication and designing technology OPS is still beyond reality. However, many of the optical components are commercialized and some of them are still in laboratory. Thus, for optical switches which are considered as future generation routers, many switch architectures are proposed by using different sets of optical components. This paper presents a detailed review of notable switch designs in past 20 years, and also presents a comprehensive literature survey of the notable papers related to optical packet switch designs.

Study of the Correction of Effects Chromatic Dispersion and Attenuation to Evaluate the Optical Transmission

2020 ◽  
Vol 41 (2) ◽  
pp. 209-214
Author(s):  
Saliha Kheris ◽  
Badra Bouabdallah
Keyword(s):  
Optical Transmission ◽  
Signal To Noise Ratio ◽  
Chromatic Dispersion ◽  
Optical Amplifier ◽  
Laser Source ◽  
Long Distance ◽  
Optical Components ◽  
Optical Detector ◽  
Fiber Optical ◽  
Dispersion And Attenuation

AbstractIn this paper, we have presented a global study of simple bonds, focusing on the main limitations introduced by different optical components as laser source, fiber, optical amplifier, and optical detector. The construction of a long-distance link requires the compensation of attenuation and chromatic dispersion phenomena. Thus, it is well known that the attenuations cause the drop of the signal intensity, whereas the pulse spreading, due to the dispersion, causes the increase of the Bit Error Rate (BER) and consequently the reduction of the signal to noise ratio (SNR). In this purpose, we have calculated the quality factor (Q) issues from the noisy signal’s simulations. We have found a Q of 7.02 to a BER of 0.8 e−12. The founding results match well with fixes norms in telecommunication field.

scholarly journals Accurate reconstruction of electric field of ultrashort laser pulse with complete two-step phase-shifting

2019 ◽  
Vol 7 ◽  
Author(s):  
Yi Cai ◽  
Zhenkuan Chen ◽  
Shuiqin Zheng ◽  
Qinggang Lin ◽  
Xuanke Zeng ◽  
...  
Keyword(s):  
Electric Field ◽  
Signal To Noise Ratio ◽  
Spectral Width ◽  
Phase Shifting ◽  
Optical Fields ◽  
Optical Components ◽  
Ultrafast Optical ◽  
Operating Stability ◽  
Balanced Detection ◽  
Ultrashort Laser

This paper presents a complete two-step phase-shifting (TSPS) spectral phase interferometry for direct electric-field reconstruction (SPIDER) to improve the reconstruction of ultrafast optical fields. Here, complete TSPS acts as a balanced detection that can not only remove the effect of the dc term of the interferogram, but also reduce measurement noises, and thereby improve the capability of SPIDER to measure the pulses with narrow spectra or complex spectral structures. Some prisms are chosen to replace some environment-sensitive optical components, especially reflective optics to improve operating stability and improve signal-to-noise ratio further. Our experiments show that the available shear can be decreased to 1.5% of the spectral width, which is only about $1/3$ compared with traditional SPIDER.

scholarly journals Wavefront optics and retinal image quality

2013 ◽  
Vol 3 (1) ◽  
pp. 1
Author(s):  
Cristina M. Oliveira ◽  
Sandra Franco
Keyword(s):  
Vision Research ◽  
Optical Quality ◽  
Wavefront Sensing ◽  
Zernike Polynomials ◽  
Secondary Effect ◽  
General Description ◽  
Wave Optics ◽  
Optical Aberrations ◽  
Optical Components ◽  
Optical Structure

With the increasing importance of optical aberrations in both vision research and clinical practice, it becomes necessary for vision scientists to have a thorough understanding of the concepts behind wavefront optics. Therefore, in this review, we provide some basic wave optics concepts useful to understand wavefront analysis, and describe the application of Zernike polynomials in the decomposition of aberrations. A general description of the human eye optical structure is given, followed by a more detailed analysis of the optical components of the eye and optical aberrations, and their secondary effect on overall optical quality. We further provide an overview of the current corneal and ocular wavefront sensing methods.

scholarly journals Can we detect regional methane anomalies? A comparison between three observing systems

2016 ◽  
Vol 16 (14) ◽  
pp. 9089-9108 ◽  
Author(s):  
Cindy Cressot ◽  
Isabelle Pison ◽  
Peter J. Rayner ◽  
Philippe Bousquet ◽  
Audrey Fortems-Cheiney ◽  
...  
Keyword(s):  
Signal To Noise Ratio ◽  
Regional Scale ◽  
Surface Flux ◽  
Uncertainty Assessment ◽  
Atmospheric Methane ◽  
Tropical Regions ◽  
Current Trends ◽  
Methane Fluxes ◽  
Surface Network ◽  
Observing Systems

Abstract. A Bayesian inversion system is used to evaluate the capability of the current global surface network and of the space-borne GOSAT/TANSO-FTS and IASI instruments to quantify surface flux anomalies of methane at various spatial (global, semi-hemispheric and regional) and time (seasonal, yearly, 3-yearly) scales. The evaluation is based on a signal-to-noise ratio analysis, the signal being the methane fluxes inferred from the surface-based inversion from 2000 to 2011 and the noise (i.e., precision) of each of the three observing systems being computed from the Bayesian equation. At the global and semi-hemispheric scales, all observing systems detect flux anomalies at most of the tested timescales. At the regional scale, some seasonal flux anomalies are detected by the three observing systems, but year-to-year anomalies and longer-term trends are only poorly detected. Moreover, reliably detected regions depend on the reference surface-based inversion used as the signal. Indeed, tropical flux inter-annual variability, for instance, can be attributed mostly to Africa in the reference inversion or spread between tropical regions in Africa and America. Our results show that inter-annual analyses of methane emissions inferred by atmospheric inversions should always include an uncertainty assessment and that the attribution of current trends in atmospheric methane to particular regions' needs increased effort, for instance, gathering more observations (in the future) and improving transport models. At all scales, GOSAT generally shows the best performance of the three observing systems.

scholarly journals Review of Issues and Solutions in High-Power Semiconductor Laser Packaging Technology

2021 ◽  
Vol 9 ◽  
Author(s):  
Yixiong Yan ◽  
Yu Zheng ◽  
Haigang Sun ◽  
Ji’an Duan
Keyword(s):  
Semiconductor Laser ◽  
Semiconductor Lasers ◽  
Thermal Management ◽  
Laser Diode ◽  
High Power ◽  
High Reliability ◽  
Beam Quality ◽  
Beam Shaping ◽  
Optical Components ◽  
Power Semiconductor

In the past 20 years, semiconductor lasers have been widely used in medical, industrial, and communication applications, providing a revolutionary and powerful platform for the fifth generation and advanced manufacturing. Semiconductor laser has the advantages of small size, lightweight, high reliability and easy modulation, becoming increasingly popular. However, due to the laser diode emission mechanism limitation, the beam quality is inferior and cannot be directly applied and required to be handled by beam shaping. However, the packaging of multiple beam shaping optical components is accompanied by risks due to misalignment. The misalignment error of the optical components has a great hidden danger to the laser performance. As semiconductor lasers' power gradually increases, lasers' thermal management technology is also increasingly strict. Therefore, this article first reviews the beam shaping technology of semiconductor laser diode array. Secondly, the analysis of the influence of the array semiconductor laser optical device's misalignment is reviewed, and a feasible solution is proposed. Finally, it summarizes the researches on thermal management in high-power semiconductor lasers. This article aims to give readers a comprehensive and broad understanding of semiconductor laser packaging's technical difficulties and to recognize each corresponding solution.

Comparison of 905 nm and 1550 nm semiconductor laser rangefinders’ performance deterioration due to adverse environmental conditions

2014 ◽  
Vol 22 (3) ◽  
Author(s):  
J. Wojtanowski ◽  
M. Zygmunt ◽  
M. Kaszczuk ◽  
Z. Mierczyk ◽  
M. Muzal
Keyword(s):  
Semiconductor Laser ◽  
Environmental Conditions ◽  
Environmental Changes ◽  
Surface Condition ◽  
Atmospheric Transmission ◽  
Standard Atmosphere ◽  
Range Finding ◽  
Maximum Range ◽  
Performance Deterioration ◽  
Adverse Environmental Conditions

AbstractLaser rangefinder performance (i.e., maximum range) is strongly affected by environment due to visibility-dependent laser attenuation in the atmosphere and target reflectivity variations induced by surface condition changes (dry vs. wet). Both factors have their unique spectral features which means that rangefinders operating at different wavelengths are affected by specific environmental changes in a different way. Current state of the art TOF (time of flight) semiconductor laser rangefinders are based mainly on two wavelengths: 905 nm and 1550 nm, which results from atmospheric transmission windows and availability of high power pulsed sources. The paper discusses the scope of maximum range degradation of hypothetical 0.9 μm and 1.5 μm rangefinders due to selected water-related environmental effects. Atmospheric extinction spectra were adapted from Standard Atmosphere Model and reflectance fingerprints of various materials have been measured. It is not the aim of the paper to determine in general which wavelength is superior for laser range finding, since a number of criteria could be considered, but to verify their susceptibility to adverse environmental conditions.

High precision linear frequency modulation ranging system based on semiconductor laser

2018 ◽  
Vol 32 (11) ◽  
pp. 1850136 ◽  
Author(s):  
Mingyuan Xue ◽  
Cunxiao Gao ◽  
Linquan Niu ◽  
Shaolan Zhu ◽  
Na Guo ◽  
...  
Keyword(s):  
Semiconductor Laser ◽  
High Precision ◽  
Frequency Modulation ◽  
Signal To Noise Ratio ◽  
Linear Frequency Modulation ◽  
Repetition Frequency ◽  
Laser Ranging ◽  
Signal To Noise ◽  
Linear Frequency ◽  
Noise Ratio

Based on the linear frequency modulation (LFM) of semiconductor laser, a laser ranging system is built. The ranging precision of the system is about micron dimension with the repetition frequency of 100 kHz and a distance of 1–10 m. We analyzed the ranging precision experimentally. As the bandwidth increases, the ranging precision becomes higher and higher. When the bandwidth is fixed, as the distance increases, the signal-to-noise ratio (SNR) will decrease, which reduces the precision.

A double-pass Sisam spectrometer for the near infrared

1975 ◽  
Vol 346 (1646) ◽  
pp. 395-412 ◽  
Keyword(s):  
Spectral Range ◽  
Near Infrared ◽  
Signal To Noise Ratio ◽  
Signal To Noise ◽  
Double Pass ◽  
Optical Components ◽  
Common Axis ◽  
Noise Ratio ◽  
Real Gain

A double-pass Sisam spectrometer of simplified design is described in which the two gratings rotate about a common axis. Sample spectra are given and the performance of the instrument is assessed and compared with that predicted theoretically. A resolution of 0.05 cm -1 has been achieved at 1.6 µm, corresponding to 90% of the maximum theoretically attainable with the gratings and configuration used. This performance was maintained over a continuously scanned spectral range of 500 cm -1 without realignment of the optical components. The instrument thus offers a real gain in signal-to-noise ratio over the equivalent, practical slit spectrometer of a factor of between 30 and 1000.

scholarly journals Upper Limit for Angular Compounding Speckle Reduction

2017 ◽  
Author(s):  
Yonatan Winetraub ◽  
Chris Wu ◽  
Steven Chu ◽  
Adam de la Zerda
Keyword(s):  
Optical Coherence Tomography ◽  
Signal To Noise Ratio ◽  
Numerical Aperture ◽  
Speckle Reduction ◽  
Literature Analysis ◽  
Spatial Averaging ◽  
Signal To Noise ◽  
Optical Aberrations ◽  
Trade Off ◽  
Upper Limit

AbstractPrevious studies of angular compounding for speckle reduction in optical coherence tomography may not have fully accounted for optical aberrations, which produce unintended spatial averaging and concomitant loss of spatial resolution. We accounted for such aberrations by aligning our system and measuring distortions in the images, and found that speckle reduction by angular compounding was limited. Our theoretical analysis using Monte Carlo simulations indicates that “pure” angular compounding over 13° (our full numerical aperture) can improve the signal-to-noise ratio by no more than a factor of 1.5, significantly lower than values reported in literature. Analysis suggests that illuminating only part of the lens to further reduce speckle also involves a trade-off with resolution roughly equivalent to spatial averaging. We conclude that angular compounding provides substantially less benefit than previously expected.

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