Showing papers on "Ring laser published in 1997"
TL;DR: In this article, the capability of ring-laser gyros for measurements of geodesic interest, including seismometry and earth tides, and for detection of other sources of non-reciprocal refractive indices, including axions and CP violation, are discussed.
Abstract: HeNe ring-laser gyros are standard sensors in inertial guidance; mirror reflectances now reach 99.9999%. Present research instruments have an area of , a passive quality factor of , and a resolution of the frequency difference of counter-rotating optical beams approaching microhertz. In the Sagnac effect, this difference is proportional to the angular velocity. Present resolution is limited by thermal drifts in frequency pulling, itself reflecting mirror backscatter. The capability of ring lasers for measurements of geodesic interest, including seismometry and earth tides, and for detection of other sources of non-reciprocal refractive indices, including axions and CP violation, are discussed. In standard polarization geometries the observable is necessarily time-reversal odd. Scaling rules for dimensions, finesse etc summarizing past progress and suggesting future potential are given.
349 citations
TL;DR: Using a single-frequency miniature Nd:YAG ring laser as a pump source results in SRO output with high spectral purity and frequency stability(<10 MHz/min), which can be continuously tuned over 2 GHz without mode hops.
Abstract: We demonstrate single-frequency operation of a cw quasi-phase-matched singly resonant optical parametric oscillator (SRO). We obtained widely tunable output from 1.66 to 1.99 µm (signal) and from 2.29 to 2.96 µm (idler) by employing a periodically poled lithium niobate multigrating chip. Using a single-frequency miniature Nd:YAG ring laser as a pump source results in SRO output with high spectral purity and frequency stability (<10 MHz/min), which can be continuously tuned over 2 GHz without mode hops. We obtain a minimum SRO threshold of 260 mW by resonating the pump wave in the SRO cavity.
102 citations
TL;DR: In this article, the dynamics of a unidirectional erbium-doped fiber laser are investigated on a time scale short enough to observe, with good resolution, its behavior for individual round-trips in the laser cavity.
Abstract: The dynamics of a unidirectional erbium-doped fiber laser is investigated on a time scale short enough to observe, with good resolution, its behavior for individual round-trips in the laser cavity. With an intracavity polarization controller, a rich variety of nonlinear phenomena, ranging from self-pulsing to square-wave antiphase patterns in two orthogonal states of polarization, are observed. These patterns evolve continuously in time. A stochastic delay-differential equation model is proposed to describe this system. Numerical simulations show that this model satisfactorily accounts for all types of qualitative behavior and reveal that the inclusion of spontaneous-emission noise is necessary to reproduce the observed continuous pattern evolution. Two different, typical types of nonlinear dynamical states are found both numerically and experimentally: a deterministic, low-dimensional regime and a noise-driven high-dimensional motion.
74 citations
TL;DR: In this paper, a method of providing asymmetric feedback in the triangular ring laser structure was devised through simple alterations of the waveguide shape, and two kinds of alterations were designed and implemented, one being the "optical diode" and the other being the tapered waveguide.
Abstract: A method of providing asymmetric feedback in the triangular ring laser structure was devised through the simple alterations of the waveguide shape. Two kinds of alterations were designed and implemented, one being the “optical diode,” the other being the tapered waveguide. Unidirectional operation was achieved for the ring lasers, with a single-beam slope efficiency of 0.23 W/A, which was the highest single-beam slope efficiency reported for semiconductor ring lasers.
68 citations
TL;DR: In this paper, it was shown that pump-source frequency noise has only a minor effect on the intensity noise of a diode-pumped Nd:YAG ring laser.
Abstract: Typically, the intensity noise of solid-state lasers is dominated by a resonant relaxation oscillation, RRO, at intermediate frequencies (kilohertz to megahertz) and by pump-source noise at frequencies below the RRO. The RRO is driven by vacuum fluctuations as well as by pump-source fluctuations and is therefore present irrespective of the pump-source noise level. However, the intensity noise at frequencies below the RRO can be substantially lowered by use of a low-noise pump source. This behavior is experimentally studied for diode-pumped Nd:YAG ring lasers. An experimental comparison is made between pumping with a single-element diode laser (SEDL) or with a diode-laser array (DLA). We find good agreement with theory for the SEDL but not for the DLA because the DLA's output intensity noise is spatially variant. We also show that pump-source frequency noise has only a minor effect on the intensity noise of the Nd:YAG laser. The requirements for low-noise operation of solid-state lasers are discussed.
54 citations
TL;DR: In this paper, a ring laser goniometer was investigated in different applications of precision angle measurement, such as the calibration of optical polygons and optical encoders, external angle measurement of rotating objects and inertial angle measurement by rotation of the goniometers itself.
Abstract: A ring laser goniometer was investigated in different applications of precision angle measurement, such as the calibration of optical polygons and optical encoders, external angle measurement of rotating objects and inertial angle measurement by rotation of the goniometer itself. The results agree with standard methods of angle measurement to about 0,5 µrad (0,1 ). Further improvement in accuracy is expected mainly from the reduction of noise in the mechanical and electrical setup of the measurement system.
50 citations
TL;DR: A compact source of stable cw single-frequency radiation at 473 nm has been realized by second-harmonic generation of a diode-pumped miniature Nd:YAG ring laser operating on the (4)F(3/2) - (4)/9/2 laser transition.
Abstract: A compact source of stable cw single-frequency radiation at 473 nm has been realized by second-harmonic generation of a diode-pumped miniature Nd:YAG ring laser operating on the (4)F(3/2) - (4)I(9/2) laser transition. By use of potassium niobate (KNbO(3)), single-longitudinal-mode output powers of 500 mW cw with high stability and maximum optical-to-optical conversion efficiencies >81% are achieved. An external semimonolithic cavity permits mode-hop-free frequency tuning of blue radiation over as much as 20 GHz.
49 citations
TL;DR: In this article, the first bidirectional operation of a Kerr-lens mode-locked femtosecond Ti:sapphire laser was reported, where a simple ABCD matrix method correctly predicts the locations of the apertures to achieve the positive feedback required for continous wave mode-locking and the negative feedback for continuous wave operation.
33 citations
TL;DR: In this paper, an active harmonically modelocked erbium-doped fiber ring laser was used to generate a 32 GHz optical pulse train with a measured pulsewidth of < 9 ps and a total jitter of < 0.2 ps.
Abstract: The generation of optical pulse trains at millimetre-wave repetition frequencies is demonstrated, using pulse repetition frequency quadrupling in an active harmonically modelocked erbium-doped fibre ring laser. A 32 GHz pulse train was generated using an RF drive frequency of 8 GHz with a measured pulsewidth of < 9 ps and a total jitter of < 0.2 ps.
29 citations
TL;DR: In this article, a high peak power all-fibre pulsed source at 1.53 /spl mu/m, based on an amplified Q-switched fiber laser was presented.
Abstract: A high peak power all-fibre pulsed source at 1.53 /spl mu/m, based on an amplified Q-switched fibre laser is presented. Peak powers higher than 2 kW and pulsewidths of /spl sim/20ns at repetition rates up to 1 kHz are demonstrated. Pumped with a single compact pump source (MOPA), this device constitutes a very powerful field pulse generator.
28 citations
TL;DR: In this paper, single-lateral mode, long-wavelength, waveguide diode-ring lasers have been fabricated in InP-InGaAsP with facets etched using CAIBE.
Abstract: Single-lateral mode, long-wavelength, waveguide diode-ring lasers have been fabricated in InP-InGaAsP with facets etched using CAIBE. The devices lase at around 1.26 /spl mu/m under pulsed testing. The lowest threshold current is around 64 mA, The best side-mode-suppression ratio (SMSR) is found to be 25.4 dB. Triangular ring lasers demonstrated significantly higher SMSR than Fabry-Perots fabricated on the same chip. Ring laser far-field and output power dependence on structural angle are also reported.
TL;DR: In this article, a numerical model for the analysis of the continuous wave operation of an erbium doped fiber ring laser is presented, which is based on the spectral model for EDFs.
TL;DR: In this paper, a 1.3 /spl mu/m actively modelocked semiconductor ring laser which generates near transform-limited pulses as short as 1.9 ps at a repetition rate of 10 GHz was presented.
Abstract: The authors report a novel 1.3 /spl mu/m actively modelocked semiconductor ring laser which generates near transform-limited pulses as short as 1.9 ps at a repetition rate of 10 GHz. The laser is constructed from discrete fibre pigtailed components and an electroabsorption modulator is used as the modelocking element.
03 Sep 1997
TL;DR: In this article, the authors analyse harmonic mode-locking at (sub)terahertz frequencies in linear Fabry-Perot compound-cavity laser diodes (theoretically), and in ring structures (experimentally and theoretically) and compare these lasers with other constructions used for harmonic mode locking.
Abstract: The authors analyse harmonic mode-locking at (sub)terahertz frequencies in linear Fabry-Perot compound-cavity laser diodes (theoretically), and in ring structures (experimentally and theoretically) and compare these lasers with other constructions used for harmonic mode-locking.
TL;DR: In this article, the pump wave is provided by a frequency-doubled miniature Nd:YAG ring laser and is resonantly enhanced in the SRO cavity, resulting in an external threshold of 200 mW.
Abstract: is demonstrated. The pump wave is provided by a frequency-doubled miniature Nd:YAG ring laser and is resonantly enhanced in the SRO cavity, resulting in an external threshold of 200 mW. Stable single-frequency emission in the 1000–1135 nm range has been obtained with 2 GHz continuous tunability and signal/idler linewidths <160 kHz.
TL;DR: In this article, a simple and novel configuration for dual wavelength operation of Er-doped fiber lasers with fiber gratings is proposed, which can achieve bit-rates up to 50 MHz.
Abstract: A simple and novel configuration for dual wavelength operation of actively mode-locked Er-doped fibre lasers with fibre gratings is proposed. Simultaneously mode-locked operation with two wavelengths at bit-rates up to 50 MHz is experimentally demonstrated.
TL;DR: It is obtained 2.5 W of single-frequency TEM(00) output at 532 nm using a Brewster-angled LBO crystal for intracavity second-harmonic generation in a diode-bar-pumped Nd:YAG laser.
Abstract: We obtained 2.5 W of single-frequency TEMoo output at 532 nm using a Brewster-angled LBO crystal for intracavity second-harmonic generation in a diode-bar-pumped Nd:YAG laser. By inserting a thin uncoated etalon, the 1061.4 nm laser transition can be selected, generating 1.6 W of output at 530.7 nm.
TL;DR: In this article, a Nd:YAG laser having a ring configuration, with Faraday rotator to provide unidirectional operation has been end-pumped by a single 20 W diode bar equipped with a beam-shaper.
16 Feb 1997
TL;DR: In this article, the phase and intensity of a short optical pulse are determined by means of an optical delay-line discriminator, and then a simple linear transform is used to obtain the phase of the original input pulse.
Abstract: We demonstrate a new technique to characterize short optical pulses, which is both simple and capable of yielding pulse characteristics in near-real time (greater than once a second). The optical pulse to be characterized is spectrally dispersed until it is long enough to be easily measured by a fast detector and electronic oscilloscope. The phase of this dispersed pulse is then determined, in our case by means of an optical delay-line discriminator. Once the phase and intensity of the dispersed pulse is known, and knowing the linear dispersion, one can use a simple linear transform to obtain the phase and intensity of the original input pulse. We have applied this technique to the characterization of subpicosecond and picosecond pulses from various fiber lasers. In one set of experiments a fiber ring laser provided roughly transform-limited pulses of 0.63 ps width at an 11-MHz repetition rate. The pulses were attenuated to 10 /spl mu/W, to eliminate any nonlinear effects, and coupled into 6 km of standard telecommunications fiber. The output of the 6 km fiber was coupled into the discriminator and the output detected using a fast detector and oscilloscope.
TL;DR: In this paper, the authors estimate the effect of the Earth's body tide deformations due to vorticity and tilt on the area vector A of a ring laser, which is used for validation of existing and future ring lasers.
Abstract: The Earth rotation vector is an integral dynamical quantity of the Earth system, with Earth rotation variations depending on the overall dynamics of the Earth system at all time scales. New observations of Earth rotation variations with a precision better than 10−9 of the Earth rotation would contribute to the understanding of many geophysical phenomena. High precision short-term observations of the projection of the Earth rotation vector ΩE on the area vector A of a ring laser are now possible. Tidally induced Sagnac effects are due to changes in the ring geometry (areal strain and perimeter variations), changes in the normal vector of the ring laser plane (tilt), and the vorticity of the Earth's tidal deformations. Here we estimate the latitude-dependent effect of the Earth's body tide deformations due to vorticity and tilt. At mid-latitudes, the vorticity δΩ is of the order 8 · 10−8ΩE, but because it is in the local horizontal plane, it is not detectable by a horizontal ring. The Sagnac effect due to tidal tilt for a horizontal ring at mid-latitudes is of the order of 4 · 10−8 of the Earth rotation effect. Thus, the tidal signal is of an order of magnitude where it may be used for validation of existing and future ring lasers.
TL;DR: In this article, the authors investigated the cause of the instability of the self-modulation frequency ωm of a monolithic Nd : YAG ring laser and proposed a method for weakening such coupling coefficients.
Abstract: An investigation was made of the cause of the instability of the self-modulation frequency ωm of a monolithic Nd : YAG ring laser. One of the main reasons for this instability was a strong temperature dependence of the effective coupling coefficients of counterpropagating waves characterising extracavity components. A method for weakening such coupling was proposed and implemented experimentally. This method made it possible to reduce the instability of the self-modulation frequency by over two orders of magnitude.
TL;DR: In this article, the authors made experimental and theoretical investigations of dynamic chaos in a ring laser with periodically modulated pumping and found regions of existence of strange attractors of two types, synchronised and nonsynchronised, in the plane of the system parameters (pump frequency and modulation depth).
Abstract: Experimental and theoretical investigations were made of dynamic chaos in a solid-state ring laser with periodically modulated pumping. Synchronised dynamic chaos in a bidirectional ring laser was demonstrated for the first time. Regions of existence of strange attractors of two types, synchronised and nonsynchronised, were found in the plane of the system parameters (pump frequency and modulation depth). Competition between these attractors was discovered. The spectra of the Lyapunov exponents and the information dimensionality were calculated for the attractors of both types.
TL;DR: In this article, the authors reported 1.5 W single-frequency output power at 1.357 /spl mu/m from a diode-pumped Nd:YAG ring laser.
Abstract: The authors report 1.5 W single-frequency output power at 1.357 /spl mu/m from a diode-pumped Nd:YAG ring laser. Suppression of the close neighbouring transitions at 1.319 and 1.338 /spl mu/m is accomplished by a sophisticated optical coating deposited by the ion-beam-sputtering technique. High intensity stability is achieved by the application of an electronic feedback loop.
TL;DR: In this paper, the Pound-Drever-Hall method was extended with a diode-pumped ring laser and a tunable optical resonator to produce a laser beam with both narrow linewidth and stable center frequency.
Abstract: A new method for controlling a laser's center frequency is reported. This method extends the Pound-Drever-Hall technique, which delivers exceptional laser linewidth. The new technique, applicable over a broad range of wavelengths, produces a laser beam with both narrow linewidth and stable center frequency. A diode-pumped ring laser is locked to an ultrahigh-finesse, tunable optical resonator which, in turn, is locked to an electronic (5 MHz) oscillator using a difference frequency developed by locking a second laser to the resonator. A 1064-nm beam is reported with linewidth less than 0.004 Hz and center-frequency stability given by the electronic reference. For the case of an oven-controlled quartz crystal, the laser center-frequency stability is less than 1 part in 10/sup 11/ per day with root Allan variance of 10/sup -12/ for a 1000-s time delay. The entire system is compact, and all elements are solid-state, making it useful both in the laboratory and in a number of space-based applications.
Patent•
06 Aug 1997
TL;DR: In this article, a multi-element, folded beam laser (200) includes a plurality of laser medium (505) elements, pumping means (240), a highly reflective reflector (220), an output coupled (225) and one or more beam directors (210, 215) for redirecting the beam through the elements and between the reflector and the output coupler.
Abstract: A multi-element, folded beam laser (200) includes a plurality of laser medium (505) elements, pumping means (240), a highly reflective reflector (220), an output coupled (225) and one or more beam directors (210, 215) for redirecting the beam through the elements (505) and between the reflector (220) and the output coupler (225). An alternate folded beam ring laser and an alternate folded beam laser amplifier are also disclosed.
TL;DR: In this paper, a pulsed Ti:Al2O3 ring laser system injection seeded with a laser diode is presented, which generates single-frequency output with Fourier-limit temporal profiles.
Abstract: A pulsed Ti:Al2O3 ring laser system injection seeded with a laser diode is presented. The Ti:Al2O3 laser generates single-frequency output with Fourier-limit temporal profiles. Temporal characteristics are systematically investigated, leading to a fact that the temporal stability of pulsed output is essentially determined by the fluctuation of the pump YAG laser output.
TL;DR: In this article, a triangular shaped ridge waveguide diode ring laser is fabricated in InP/InGaAsP. The laser facets are etched using Cl2 RIBE and the device lases at 1.21 µm under room temperature pulsed testing.
Abstract: A triangular shaped ridge waveguide diode ring laser is fabricated in InP/InGaAsP. The laser facets are etched using Cl2 RIBE. The device lases at 1.21 µm under room temperature pulsed testing.
TL;DR: An analytical steady-state solution for a singlemode homogeneously-broadened two-level Fabry-Perot laser, valid for any field intensity, cavity detuning and level population decay rates, is obtained in this article.
TL;DR: The architectures for OTDMA networks are described, and all-optical clock recovery schemes that are based on traveling-wave semiconductor laser amplifiers, self-pulsating laser diodes, EO switches, and four-wave mixing are looked at.
Abstract: Review current OTDMA technology, with the emphasis on optical clock recovery and time demultiplexing. Various optical switching techniques are surveyed, and they are compared by taking account of the potential feasibility of engineering implementation. The architectures for OTDMA networks are described, and we look at all-optical clock recovery schemes that are based on traveling-wave (TW) semiconductor laser amplifiers, self-pulsating laser diodes, EO switches, mode locking of a fiber ring laser, and four-wave mixing (FWM). We also review various optical switching techniques for ultrafast time demultiplexing.
TL;DR: An orthogonal linear polarization operated ring laser with a superluminescent diode has been demonstrated to generate a tunable optical beat signal.
Abstract: An orthogonal linear polarization operated ring laser with a superluminescent diode has been demonstrated to generate a tunable optical beat signal. The ring cavity contains a superluminescent diode as the optical gain medium, Faraday rotators, and a variable phase retarder (Babinet-Soleil compensator). By controlling the retarder, we changed the beat frequency in the range from a few tens of megahertz to 100 MHz.