Proceedings ArticleDOI
Interferometer-less coherent optical range finder
Chen-Chia Wang,Sudhir Trivedi,Feng Jin,Jacob B. Khurgin,Doyle Temple,U. Hommerid,E. Gad,A. Corder +7 more
- pp 376-377
TLDR
In this article, the authors proposed a coherent optical range finder (CFDR) which is a hybrid of direct and coherent detection optical range findsers, and achieved a spatial resolution of approximately 15 /spl mu/m using a widely tunable (75 nanometers) solid state laser.Abstract:
Summary form only given. Optical techniques for non-contact measurements of distances can be generalized into two main categories: direct detection and coherent detection techniques. In direct detection systems, the time delays of short laser pulses are used to determine target distances. The resultant spatial resolution, however, is quite limited due to the difficulty in measuring small time delays. On the other hand, optical interferometers are used in coherent detection range finders with the laser wavelength being used as the gauge against target distances. Interferometer-based coherent optical range finder can offer nanometer-scale high precision measurements. However, the readout from an interferometer is a sinusoidal function of the path length and hence the measurement range is severely limited. Optical coherent frequency domain reflectometry (CFDR) resembles a hybrid of direct and coherent detection optical range finders. Because the laser frequency is linearly chirped as a function of time in CFDR systems, any imbalance in the lengths of the reference and probe paths results in finite amount of optical frequency difference between the two interfering laser beams. By measuring the optical frequency difference, target distance can be determined with precision unattainable by direct detection techniques. indeed, a spatial resolution of approximately 15 /spl mu/m was achieved using a widely tunable (75 nanometers) solid state laser.read more
Citations
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Journal ArticleDOI
Terahertz Imaging Systems With Aperture Synthesis Techniques
Viktor Krozer,Torsten Löffler,Jørgen Dall,Anders Kusk,Finn Eichhorn,R K Olsson,Jonas Christian Due Buron,Peter Uhd Jepsen,Vitaliy Zhurbenko,T. Jensen +9 more
TL;DR: Active multichannel measurement method is found to be promising for real-time applications among the various terahertz imaging techniques and is chosen as a basis for the imaging instruments presented in this paper.
Journal Article
Optical frequency-domain reflectometry using rapid wavelength tuning of a Cr4+:forsterite laser
TL;DR: A cw chromium-doped forsterite laser that permits rapid wavelength tuning over a broad bandwidth is presented and the application of this source to frequency-domain ranging and optical tomography is demonstrated.
Dissertation
Infrared ranging in multipath environments for indoor localization of mobile targets
TL;DR: In this paper, a sistema de medida with senales opticas, aplicada a la localizacion of agentes moviles in espacios interiores, is presented.
Proceedings ArticleDOI
Experimental demonstration of impact of amplified spontaneous emission on devices based on cross-gain modulation in semiconductor optical amplifiers
Bipin Sankar Gopalakrishna Pillai,Ka-Lun Lee,Ampalavanapillai Nirmalathas,Malin Premaratne,Christina Lim +4 more
TL;DR: In this paper, the impact of Amplified Spontaneous Emission (ASE) noise on a Semiconductor Optical Amplifier (SOA)-based optical pulse delay discriminator and SOA-based distance ranger was investigated.
References
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Journal ArticleDOI
Optical frequency-domain reflectometry using rapid wavelength tuning of a Cr4+:forsterite laser.
TL;DR: In this paper, a chromium-doped forsterite laser was used for frequency-domain ranging and optical tomography with a scan rate of 2 kHz and an axial resolution of 15 microm.
Journal ArticleDOI
Integrated time-of-flight laser radar
TL;DR: In this paper, a hand-held pulsed time-of-flight (TOF) laser radar device has been designed and tested and an accuracy of 35 mm is achieved with a measuring time of 200 ms between temperatures of -10/spl deg/C and +30/spl dc/C. Power consumption during continuous measurement is 0.84 W.
Journal ArticleDOI
Spectral broadening of pulsating Al x Ga 1-x As double heterostructure lasers
TL;DR: In this paper, the longitudinal mode spectrum of stripe geometry double heterostructure (DH) lasers exhibits a spectral broadening of ∼ 0.8 A when the laser emits pulsations, which is due to an increase of the refractive index resulting from the reduction in the carrier concentration during the pulse.
Journal ArticleDOI
Simple laser velocimeter that uses photoconductive semiconductors to measure optical frequency differences
TL;DR: A simple laser velocimeter that uses a semi-insulating GaAs:Cr sample to detect the Doppler frequency shift between two laser beams is demonstrated.
Patent
Double heterostructure laser
John C. Connolly,Dan Botez +1 more
TL;DR: In this article, a semiconductor laser comprising a substrate having a plurality of closely spaced channels with mesas separating the channels to form a channelled region in the surface of the substrate is presented.