Showing papers on "Tunable laser published in 1991"
AT&T1
TL;DR: In this paper, the dynamic, polarization, and transverse mode characteristics of InGaAs-GaAs quantum well vertical cavity surface emitting lasers (VCSELs) emitting at 0.98 mu m are investigated.
Abstract: The dynamic, polarization, and transverse mode characteristics of strained InGaAs-GaAs quantum well vertical cavity surface emitting lasers (VCSELs) emitting at 0.98 mu m are investigated. The dynamic behavior of VCSELs with high and low operating voltages and series resistances is compared. A large wavelength chirp in the lasing spectrum was observed for the lasers with high voltage/resistance, even under low-duty-cycle pulse operation. This is thought to be due to resistive heating close to the laser junction. It is observed that the transverse mode structure of VCSELs and their dependence on laser dimensions and drive current are highly analogous to those of edge emitting lasers, whereas the polarization characteristics of the two types of lasers are significantly different. >
406 citations
TL;DR: An external cavity has been developed for use with commercial diode lasers that uses a diffraction grating at grazing incidence for wavelength selection and output coupling and is useful for high-resolution spectroscopy, laser cooling of atoms, time standards, and coherent optical communications.
Abstract: An external cavity has been developed for use with commercial diode lasers. It uses a diffraction grating at grazing incidence for wavelength selection and output coupling. This configuration allows a GaAlAs diode laser to be tuned conveniently anywhere in a range greater than 20 nm. Also, the linewidth is reduced by a factor of more than 1000 from 40 MHz to less than 10 kHz. The new laser system should be useful for high-resolution spectroscopy, laser cooling of atoms, time standards, and coherent optical communications.
343 citations
TL;DR: In this article, the authors obtained 140 unique, uniformly separated, single-mode wavelength emissions from a 7*20 VCSEL array and obtained a large total wavelength span (approximately 430 AA) and small wavelength separation (approximately 3 AA) with uncompromised laser performance.
Abstract: Techniques to achieve wavelength multiplexing and tuning capabilities in vertical-cavity surface-emitting lasers (VCSELs) are described, and experimental results are given. The authors obtained 140 unique, uniformly separated, single-mode wavelength emissions from a 7*20 VCSEL array. Large total wavelength span ( approximately 430 AA) and small wavelength separation ( approximately 3 AA) are obtained simultaneously with uncompromised laser performance. All 140 lasers have nearly the same threshold currents, voltages, and resistances. Wavelength tuning is obtained by using a three-mirror coupled-cavity configuration. The three-mirror laser is a two-terminal device and requires only one top contact. Discrete tuning with a range as large as 61 AA is achieved with a small change in drive current of only 10.5 mA. >
193 citations
Book•
01 Jan 1991
TL;DR: In this article, the authors proposed a line broadening of Semiconductor Lasers to increase the spectral line width of complicated structure Lasers, and showed that the linebroadening can be used to improve the spectral properties of complex structure laser structures.
Abstract: Line Broadening of Semiconductor Lasers (C. Henry). Modulation and Noise Spectra of Complicated Laser Structures (O. Nilsson, et al.). Frequency Tunability, Frequency Modulation, and Spectral Linewidth of Complicated Structure Lasers (Y. Yoshikuni). Spectroscopy by Semiconductor Lasers (M. Ohtsu & K. Nakagawa). Coherent Detection Using Semiconductor Lasers: System Design Concepts and Experiments (T. Hodgkinson). Traveling--Wave Semiconductor Laser Amplifiers (T. Saitoh & T. Mukai). Semiconductor Laser Amplifiers in High--Bit--Rate and Wavelength--Division--Multiplexed Optical Communication Systems (R. Jopson & T. Darcie). Injection--Locked Semiconductor Laser Amplifiers (S. Kobayashi). Photon Statistics and Mode Partition Noise of Semiconductor Lasers (P. Liu). Squeezed--State Generation by Semiconductor Lasers (Y. Yamamoto, et al.). Generation of Photon--Number--Squeezed Light by Semiconductor Incoherent Light Sources (M. Teich, et al.). Controlled Spontaneous Emission in Microcavity Semiconductor Lasers (Y. Yamamoto, et al.). Index.
142 citations
TL;DR: In this article, a high performance 1.5 μm wavelength laser has been fabricated on GaAs substrates using the bonding by atomic rearrangement (BAR) technique.
Abstract: A technique, namely bonding by atomic rearrangement has been invented to realize high quality heteroepitaxy for lasers and optoelectronics. High performance lasers of 1.5 μm wavelength have been fabricated on GaAs substrates using this method. The laser has the same threshold current and quantum efficiency as lasers on InP substrates. No performance degradation has been observed. The transmission electron microscopic results show that the heteroepitaxy is excellent, without a single threading dislocation or stacking fault.
142 citations
TL;DR: In this paper, the effects of external optical feedback on the spectra of VCSELs (vertical-cavity surface-emitting lasers) were measured and it was shown that the sensitivity to optical feedback is comparable to that of conventional edge-emiting lasers such as DFBs despite their significantly different structures.
Abstract: The measurement of the effects of external optical feedback on the spectra of VCSELs (vertical-cavity surface-emitting lasers) is reported. It is surprising that VCSELs have a sensitivity to optical feedback comparable to that of conventional edge-emitting lasers such as DFBs despite their significantly different structures. This is because the extremely short cavity length of VCSELs negates the effects of their highly reflective output mirrors. As in edge-emitting lasers, VCSELs exhibit well-defined regimes of feedback effects in their spectra. Since optical isolators cannot be easily applied to VCSELs due to their array structure, these lasers may be most useful in applications which are not sensitive to the spectral qualities of the light source. >
123 citations
TL;DR: Tunable, flashlamp-pumped laser properties are described for the crystal Cr:LiSrAlF6 (Cr:LiSAF) in both long pulse and Q-switched modes of operation.
Abstract: Tunable, flashlamp‐pumped laser properties are discribed for the crystal Cr:LiSrAlF6 (Cr:LiSAF) in both long pulse and Q‐switched modes of operation. Slope efficiencies of 5%, overall efficiency of 3%, and a tuning range from 780 to 1010 nm are reported.
108 citations
TL;DR: Stable pulses of less than 150 fsec are generated directly from a tunable cw passively mode-locked Ti:sapphire laser, through a balance of self-phase modulation in the Ti:Sapphire rod and negative group-velocity dispersion produced by a prism pair.
Abstract: Stable pulses of less than 150 fsec are generated directly from a tunable cw passively mode-locked Ti:sapphire laser, through a balance of self-phase modulation in the Ti:sapphire rod and negative group-velocity dispersion produced by a prism pair. After external fiber compression, 50-fsec pulses are obtained at approximately 750 nm.
95 citations
TL;DR: In this article, a tunable far infrared laser spectrometer based on frequency mixing of an optically pumped molecular gas laser with tunable microwave radiation in a Schottky point contact diode is presented.
Abstract: A detailed description is presented for a tunable far infrared laser spectrometer based on frequency mixing of an optically pumped molecular gas laser with tunable microwave radiation in a Schottky point contact diode. The system has been operated on over 30 laser lines in the range 10–100 cm^–1 and exhibits a maximum absorption sensitivity near one part in 10^6. Each laser line can be tuned by ±110 GHz with first-order sidebands. Applications of this instrument are detailed in the preceding paper.
92 citations
01 May 1991
TL;DR: In this paper, an airborne tunable diode laser instrument is described that is capable of operating in two measurement modes, one mode provides high precision (0.1 percent CH4; 1 percent CO) measurements of CH4 and CO with a 5 second response time, and a second mode achieves the very fast response time that is necessary to make airborne eddy correlation flux measurements.
Abstract: An airborne tunable diode laser instrument is described that is capable of operating in two measurement modes. One mode provides high precision (0.1 percent CH4; 1 percent CO) measurements of CH4 and CO with a 5 second response time, and a second mode achieves the very fast response time that is necessary to make airborne eddy correlation flux measurements. Examples of data from atmospheric expeditions of the Global Tropospheric Experiment are presented.
87 citations
TL;DR: In this article, a tuning range of 160 nm has been demonstrated with an InGaAsP/InP MQW laser in a grating extended cavity across the 1.3 μm optical fiber communications window.
Abstract: A tuning range of 160 nm has been demonstrated with an InGaAsP/InP MQW laser in a grating extended cavity across the 1.3 μm optical fibre communications window. The device tuned continuously from 1.255 μm to 1.417 μm with a CW power output of over 40 mW at 1.336 μm.
TL;DR: In this paper, the optical properties of the nonlinear crystals lithium borate (LBO), barium borate and deuterated potassium phosphate (KD*P) are compared for second and third harmonic generation of Nd:YAG laser radiation.
Abstract: The optical properties of the nonlinear crystals lithium borate (LBO), barium borate (BBO) and deuterated potassium phosphate (KD*P) are compared for second and third harmonic generation of Nd:YAG laser radiation. In an experimental investigation the conversion efficiency has been measured as a function of the energy density of 8 ns long laser pulses, generated by a commercial Nd:YAG oscillator-amplifier system. In LBO and BBO the second harmonic generation saturates at an energy density of about 1.5 J cm−2 at efficiencies of 55–60%. In KD*P comparable efficiencies (40–55%) require energy densities of 2–2.6 J cm−2. Similar results are obtained for frequency tripling. In LBO and BBO saturated efficiencies of 20–25% are measured at an energy density of about 1.5 J cm−2. In KD*P efficiencies of 20% are obtained at energy densities exceeding 2 J cm−2. Besides for doubling and tripling of Nd:YAG laser radiation the phase-matching is calculated for frequency conversion of tunable laser light. The results demonstrate that in LBO and BBO phase-matched sum-frequency mixing of UV and infrared laser light generates tunable radiation at wavelengths as short as the transmission cut-off at 160 nm and 190 nm, respectively.
Patent•
21 Jun 1991
TL;DR: In this paper, a laser wavelength controlling apparatus adapted for controlling the wavelength of a narrow-band oscillation laser beam at a high accuracy for long period of time even if environmental conditions such as the atmospheric temperature and pressure changes to some degree.
Abstract: A laser wavelength controlling apparatus adapted for controlling the wavelength of a narrow-band oscillation laser beam at a high accuracy for long period of time even if environmental conditions such as the atmospheric temperature and pressure changes to some degree. This wavelength controlling apparatus includes a wavelength selective element (2) for narrowing the band width of the oscillating laser beam; a wavelength selection controller 9 and a wavelength selective element driver for changing the wavelength to be selected by the wavelength selective element (2); a reference light source (7) for generating a reference light for measuring the wavelength of the oscillating laser beam; a wavelength detector (8) for leading said oscillating laser beam and said reference light into a spectroscope and detecting the absolute wavelength of said oscillating laser beam on the basis of the detected value of the reference light; and a wavelength detecting driver (8a) for controlling the wavelength to be selected by said wavelength selective element in cooperation with said wavelength controller (9) so as to correspond the absolute wavelength detected by the wavelength detector with the preset wavelength.
CNET1
TL;DR: In this article, a wavelength tunability of 82 nm without mode hopping has been obtained with an external cavity semiconductor laser emitting around 1540 nm by combined rotation/translation of a diffraction grating.
Abstract: A wavelength tunability of 82 nm without mode hopping has been obtained with an external cavity semiconductor laser emitting around 1540 nm by combined rotation/translation of a diffraction grating. This demonstrates for the first time the tunability of an optical oscillator having a spectral purity better than 100 kHz over more than 10,000 GHz.
TL;DR: In this paper, the design, fabrication and characterisation of 1024-element matrix addressable vertical cavity surface emitting laser (VCSEL) arrays are described. And a matrix addressing architecture is employed, which enables the individual addressing of each of the 1024 lasers using only 64 electrical contacts.
Abstract: The design, fabrication and characterisation of 1024-element matrix addressable vertical cavity surface emitting laser (VCSEL) arrays are described. A strained InGaAs quantum well VCSEL structure was grown by molecular beam epitaxy and an array of 32×32 lasers was defined using a proton implantation process. A matrix addressing architecture was employed, which enables the individual addressing of each of the 1024 lasers using only 64 electrical contacts. All the lasers in the array, measured after the laser definition step, were operating with fairly homogeneous characteristics; threshold current of 6.8 mA and output quantum differential efficiency of about 8%.
TL;DR: In this article, the authors studied the IM and FM characteristics of a vertical-cavity surface-emitting laser (VCSEM) at a very low bias (4.5 mA) and demonstrated five Gb/s pseudorandom direct intensity modulation with open eyes.
Abstract: The IM (intensity modulation) and FM (frequency modulation) characteristics of vertical-cavity surface-emitting lasers are studied. The laser has high FM efficiency and broad IM bandwidth (near 8 GHz) at a very low bias (4.5 mA). Five Gb/s pseudorandom direct intensity modulation of this laser with open eyes is demonstrated. >
TL;DR: In this article, the external cavity stabilization method for diode laser spectroscopy has been proposed, which requires an anti-reflection coating on one facet of the diode, but does not require any specialized equipment.
TL;DR: What is to the authors' knowledge the first narrow-linewidth, continuously tunable laser that uses an acousto-optic filter to achieve a broad tuning range is reported, although the laser wavelength hopped between nearby longitudinal modes because of path-length fluctuations.
Abstract: We report what is to our knowledge the first narrow-linewidth, continuously tunable laser that uses an acousto-optic filter to achieve a broad tuning range. The unidirectional ring-laser configuration incorporates an erbium-doped fiber amplifier as the gain medium and an integrated, frequency-shift-compensated acousto-optic filter as the tuning element. Using a 980-nm optical pump with 60 mW of launched power, we obtained nearly 2 mW of laser output with 10% output coupling. A tuning range of 40 nm was achieved, centered about 1545 nm. Single-longitudinal-mode operation with a 10-kHz linewidth was demonstrated, although the laser wavelength hopped between nearby longitudinal modes because of path-length fluctuations. Wavelength switching at rates up to 100 kHz was examined.
TL;DR: In this article, an all fiber, diode-pumped, electrically tunable ring laser is reported. Gain is provided by an erbium-doped fiber and tuning by a fibre Fabry-Perot etalon.
Abstract: An all fibre, diode-pumped, electrically tunable ring laser is reported. Gain is provided by an erbium-doped fibre and tuning by a fibre Fabry-Perot etalon. The threshold at l.566 μm is 2.9mW, the slope efficiency is 0.15 and the output power is 4.2 mW with 32 mW of pump power. The output wavelength can be tuned from 1.525 to 1.586 μm with a variation in power of less than 3.5 dB.
TL;DR: In this paper, the Er:Ti:LiNbO/sub 3/ channel waveguides have been investigated for the /sup 4/I/sub 13/2/ level.
Abstract: Fabrication and characterisation of Er:Ti:LiNbO/sub 3/ channel waveguides is reported. A lifetime of 2.4+or-0.2 ms has been measured for the /sup 4/I/sub 13/2/ level. In a pump and probe experiment using a high power InGaAsP laser and a tunable DBR laser, a signal increase of 0.75 dB for a transmitted pump power of 4.8 mW was demonstrated.
TL;DR: In this article, an actively mode-locked erbium-doped ring laser with birefringent polarisation-maintaining fiber was used to produce dual pulses with different peak wavelengths and durations as short as 2ps.
Abstract: Dual pulses each with different peak wavelengths and durations as short as 2ps were concurrently produced with an actively mode-locked erbium-doped fibre ring laser made in part with birefringent polarisation-maintaining fibre. Peak wavelength separations measured in the experiment agreed well with the theoretical values.
TL;DR: In this article, the nonlinear gain effect can be explained by the spectral hole burning theory, and it was shown that the non-linear gain suppression coefficient can be attributed to the spectral holes burning theory.
Abstract: For the first time, the oscillation wavelength and the laser structure dependence of the K factor and of the nonlinear gain suppression coefficient e in semiconductor lasers were systematically investigated. As a result, we suggest that the nonlinear gain effect can be explained by the spectral hole burning theory.
TL;DR: The system described herein provides the capability for measuring ambient concentrations of this gas with a precision in the range from +/-0.3 to +/-1% over time periods of many hours, providing an important new capability forasuring true spatial and temporal variations of carbonyl sulfide in the atmosphere.
Abstract: A versatile and integrated tunable diode laser system for high precision measurements of the important sulfur gas carbonyl sulfide is described. We explicitly address some of the major factors affecting tunable diode laser measurement precision as well as accuracy and have implemented a number of new features for increased system control and versatility. The system described herein provides the capability for measuring ambient concentrations of this gas with a precision in the range from ±0.3 to ±1% over time periods of many hours. Such a precision provides us with an important new capability for measuring true spatial and temporal variations of carbonyl sulfide in the atmosphere.
07 Apr 1991
TL;DR: A galvanometer-driven unit that can attain at least 200 Hz tuning without the need for additional equipment or algorithms is presented, and it was shown that this type of galvanometer is also suitable for heterodyne detection lidar tuning.
Abstract: A device for rapidly tuning both CW (continuous-wave) and TEA (transversely excited atmospheric) CO/sub 2/ lasers is presented. This galvanometer-driven unit is of considerable importance over that previously reported in that it can attain at least 200 Hz tuning without the need for additional equipment or algorithms. Tuning a TEA laser at repetition rates of 200 Hz has been demonstrated for even the widest excursions, corresponding to tuning over the entire CO/sub 2/ spectrum. No amplitude-dependent adjustments were needed for even the weakest available transitions. CW laser tuning was also demonstrated to approximate this limit, and it was shown that this type of galvanometer is also suitable for heterodyne detection lidar tuning. >
IBM1
TL;DR: In this article, the characteristics of three-step photo-ionization, through an autoionizing level, of a complex atom using three single-mode pulsed dye lasers are investigated.
Abstract: In a high J-value scheme (photo-excitation sequence), the authors investigate the characteristics of three-step photo-ionization, through an autoionizing level, of a complex atom using three single-mode pulsed dye lasers. The report covers (1) ion yield dependence on the balance of three laser intensities; (2) AC Stark effect, observed in intermediate excitation; and (3) multi-photon-resonance effect in a stepwise near-resonant excitation. The experimental results are discussed through comparison with the theoretical analyses, that include the effects of magnetic sublevel degeneracy.© (1991) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
TL;DR: The first continuously wavelength-tunable vertical cavity surface emitting laser is reported in this article, where the total tuning range is 18 AA (540 GHz) including a 4-6 AA blue shift.
Abstract: The first continuously wavelength-tunable vertical cavity surface emitting laser is reported. The total tuning range is 18 AA (540 GHz) including a 4-6 AA blue shift. The laser power remains nearly constant with the tuning current for most of the tuning range. No mode hopping was observed. Using time-resolved spectrum measurement, the tuning time is determined to be approximately 300-400 ns.
TL;DR: In this paper, a wide-range electronically wavelength-tunable InGaAsP-InP laser has been developed, which is based on interferometric principles and achieves very large tuning ranges for 22 and 23 nm.
Abstract: A wide-range electronically wavelength-tunable InGaAsP-InP laser has been developed. This monolithic single-mode light source is based on interferometric principles. The authors report on successful fabrication and first experimental device characteristics obtained with these novel Y-coupled-cavity integrated interferometric injection lasers. For both the 1300 and 1500 nm wavelength regions, very large tuning ranges for 22 and 23 nm. respectively, were achieved by proper current adjustment. The minimum achieved linewidth of the nonoptimized devices is 35 MHz. Within the complete tuning range, the selection of 12 individual single-mode channels spaced by 2 nm is demonstrated with high-modulation bandwidths up to 5 GHz. A preliminary test of the wavelength switching behavior between two individual single modes indicates promising high-speed switching capabilities in the gigahertz range. >
TL;DR: In this article, the surface recombination velocity of exposed GaAs is not exacerbated in deep etched lasers; other loss mechanisms in shallow etched lasers have comparable impact on laser performance, while devices fabricated by a combination of etching and ion implantation possess lower threshold current.
Abstract: GaAs quantum well vertical-cavity surface emitting lasers fabricated using low damage reactive ion etching are discussed. Lasers which are partially and completely etched through their structure are compared. The surface recombination velocity of exposed GaAs is not exacerbated in deep etched lasers; other loss mechanisms in shallow etched lasers have comparable impact on laser performance. Etched lasers exhibit low voltage and small differential series resistance at threshold, while devices fabricated by a combination of etching and ion implantation possess lower threshold current. It is found that reactive ion etching has little additional effect on laser operation, whereas the different device structures considered do influence laser performance. >