A laser is light amplification by stimulated emission of radiation. We will develop chipscale components at 780795 nm, for a superluminal ring laser gyroscope and accelerometer srlga using rubidium. Practical considerations on the multilayer mirrors for superluminal ring laser gyroscopes article pdf available in scientific reports 5. The maximum sensitivity measured in all of these methods was of the order of 106 7, 8. Schematic of superluminal ring laser gyro with four higlectivity.
A ring laser gyroscope employs a ring laser to measure rotation. Novel expressions are derived, while the auxiliary passive cavity is. May 29, 20 based on these results, we envision a fast light enhanced ring laser gyroscope rlg that will use only a few meters of fiber and require moderate pump power only a few 100s of mw. We show here that the effective dispersion experienced by the lasing frequency is still sensitive to the spectral profile of the unsaturated gain. Schematic of superluminal ring laser gyro with four higlectivity mirrors m 1, m 2, m 3 and m 4, in which m 4 is the one with huge group delay induced by multilayer coatings, m 3 is the. Earth rotation measured by a chipscale ring laser gyroscope yuhung lai 1, myounggyun suh, yukun lu, boqiang shen 1, qifan yang, heming wang 1, jiang li, seung hoon lee, ki youl yang 1, kerry vahala y 1t.
The fundamental concept behind laser gyroscopes is fairly simple, a laser gyroscope is just an optical gyroscope that is also a laser. We use cookies to improve website performance, facilitate information sharing on social media and offer advertising tailored to your interests. Pdf sensitivity enhancement of ring laser gyroscope using. Gyroscopes are used in navigation systems for aircraft and ships, and for guidance systems in missiles and precision weapons.
This paves the way for realizing a fastlight enhanced ring laser gyroscope, for example. Nov 18, 2014 we propose and analyze a superluminal ring laser gyroscope rlg using multilayer optical coatings with huge group delay gd. A ring laser gyroscope consists of a ring laser having two counter propagating modes over the same path in order to detect rotation. Gg20an digital laser gyro the honeywell gg20 digital. Pdf design of a superluminal ring laser gyroscope using. An ultrasensitive and compact superluminal ring laser. The gyroscopic scale factor k is calculated in an active laser gyro with a dispersive. This superluminal rlg is based on a traditional rlg with minimal re. Slightly above lasing threshold, in the broken symmetry regime near. This patent document claims the benefits of three u. It operates on the principle of the sagnac effect which shifts the nulls of the internal standing wave pattern in response to angular rotation.
We will present the design that is based on proven, commercially available technologies. A ring laser gyroscope is a precision instrument that uses a laser beam traveling in two directions to measure changes in angle, or a direction. Recently, we have shown that the frequency of a superluminal ring laser srl becomes highly sensitive to perturbations. Aug 20, 2019 ring laser gyroscopes, in which rotation is detected by the sagnac effect between counterpropagating lasers, are in common use in navigation applications. Superluminal gyroscopes in conventional ring laser gyroscopes, sensitivity increases with cavity size. The sagnac effect is employed in current technology. It has also been shown that the change in the resonant frequency of the socalled white light cavity,,, which is a passive version of the srl and contains a critically tuned fast light medium, as a function of a change in the cavity. Us8514400b2 optical gyroscope sensors based on optical.
Osa superluminal ring laser for hypersensitive sensing. A simple approach might make use of a gain profile with two adjacent peaks as used for realizing a wlc. Both optical gyroscopes, the ring laser gyro rlg and the fiberoptic gyro fog, are based on the same sagnac effect 1 and 2, which shows that light traveling along a closed ring path in opposite directions allows one to detect rotation with respect to inertial space. The idea behind the ring laser gyroscope actually dates back to 19, when a french physicist, georges sagnac, experimented with rays of light. The sagnac effect for the mgx or for the ring laser gyroscopes is much larger than the coriolis effect, since the sagnac effect now is proportional to the radius of rotation. Watson laboratory of applied physics, california institute of technology, pasadena, california 91125, usa these authors contributed equally to this work. Osa theoretical modeling and experimental demonstration of. Under phase i, we have demonstrated the feasibility of the srla. Based on these results, we envision a fast light enhanced ring laser gyroscope rlg that will use only a few meters of fiber and require moderate pump power only a few 100s of mw. Shahriar, joshua yablon, zifan zhou, ye wang, shih tseng, spie optics and photonics conference, san diego, ca, august, 20. Theoretical modeling and experimental demonstration of raman.
We have demonstrated experimentally a diodepumped alkali laser dpal with a raman resonance induced dip in the center of the gain profile, in order to produce an anomalous dispersion, necessary for making the laser superluminal. Mar 15, 2011 the embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows. Onchip modulation for rotating sensing of gyroscope based. We also refer briefly to recent experimental work we have done to establish key aspects of this gyroscope. Rotation and acceleration sensor based on nondegenerate ring. We study theoretically a superluminal laser system comprising active and passive lossy coupled microresonators with equal gainloss. Another scheme devised to increase the sensitivity of an optical gyroscope is the introduction of an active laser medium in a ring cavity, as shown in figure 2. The interference between the counter propagating beams. It is shown that when the system satisfies the white light cavity wlc condition, corresponding to zero group index, it also forms a ptsymmetric system ptss at its exceptional point ep. The same mechanism can be used to produce a superluminal ring laser accelerometer srla, with a similar improvement in accuracy. The basic interferometer is modified to become a ring resonator with l as the perimeter.
If the dispersion is negative and sufficiently large, then ng. An overview of optical gyroscopes theory, practical. A typical ring laser has a cavity length of about 15 cm, so the group delay time should be approximately 0. Nov 29, 2017 furthermore, these systems are too large for many platforms. Study of white light cavity effect via stimulated brillouin. Ring laser gyroscopes can be used as the stable elements for one degree of freedom each in an inertial reference system. In order to obtain a practical superluminal ring laser gyroscope, the extinction coe cient of coating materials should be less than 1e10, which is a challenge at present. A ring laser gyro produces laser beams that travel in opposite directions around a closed triangular cavity. Sensors free fulltext modeling and implementation of. Vii, we outline an explicit scheme for realizing fastlightenhanced gyroscope, and present numerical estimates for the prospect of measuring the lensthirring rotation using such a gyroscope.
This effect shows that the propagation time of light. Ultrahigh precision absolute and relative rotation. These gyroscopes have a potential to be used in medium size. Download scientific diagram schematic of superluminal ring laser gyro with four higlectivity mirrors m1, m2, m3 and m4, in which m4 is the one with huge. Measuring the earths rotation rate using a lowcost mems. Earth rotation measured by a chipscale ring laser gyroscope. Enhanced scale factor ring laser gyroscope honeywell.
Envelope, group and phase velocities in a nested frequency. In order to measure the azimuth between the observer and the north direction very accurately, we propose a multiposition noncontinuous rotation gyro north finding scheme. In the 1980s, laser gyroscopes began to take over the work of their mechanical, and later, electronic, forebears, without the slightest resemblance in principle or operation to the earlier devices. Modeling and analysis of an ultrastable subluminal laser. Even when the global positioning system gps signal is blocked, a rate gyroscope gyro north finder is capable of providing the required azimuth reference information to a certain extent. Pdf on jan 1, 2019, maryam soltani and others published sensitivity enhancement of ring laser gyroscope. Pdf practical considerations on the multilayer mirrors. Ultrasensitive and compact superluminal ring laser. In this paper, we show a passive resonator based optical gyroscope whose sensitivity can be. Note that if the broadening linewidth induced by anomalous dispersion is less than or slightly more than stl, the frequency stabilization of laser is very difficult.
Recently, we have shown that the fast light effect and its manifestation in the white light cavity effect can be used to realize a superluminal ring laser gyroscope srlg that can be 106 times more sensitive when compared to a conventional ring laser gyroscope rlg of the same size. A ring laser gyroscope with dielectricgraphene photonic crystal. Design of a superluminal ring laser gyroscope using multilayer. According to stokes rule an integration of angular velocity. Thus, using multilayers optical coatings with huge group delay in superluminal ring laser gyroscope should be potential to realize a superluminal enhanced laser gyroscope. A superluminal ring laser gyroscope srlg can improve the accuracy of rotation sensing by nearly five orders of magnitude. Principles of aircraft gyroscopic instruments aircraft.
By definition, the group velocity of a superluminal laser exceeds the velocity of light in vacuum, which means that the group index, n g, is less than unity. Superluminal propagation through 500 m optical fiber via. To see why, consider, for example, a ring laser gyroscope rlg. Ring laser gyroscopes rlgs are also based on the sagnac e. However, because it operates on a strong absorption band, the propagating distance and the time advancement of fast light is severely restricted. Ultrahigh precision absolute and relative rotation sensing. Numerical calculations match closely with experimental results, and indicate that the laser is operating superluminally, with the group index far below unity 0. Note that the operating life, specified as,2000 hrs, is defined as time during which the gyro is economically repairable a photograph of the gyroscope is shown in figure 12. We demonstrate experimentally a superluminal ring laser based on optically pumped raman gain, and a selfpumped raman depletion for producing anomalous dispersion, employing two isotopes of rubidium.
Design of a superluminal ring laser gyroscope using. At a first glance, it is far from obvious as to how one might realize such a laser. In this system, a data pulse can be delayed an arbitrary amount of time, without significant distortion. The group velocity of light becomes superluminal in a medium with a tuned negative dispersion, using two gain peaks, for example.
Effect of cascaded brillouin lasing due to resonant pumps in a superluminal fiber ring laser gyroscope mohamed fouda, minchuan zhou, honam yum, selim shahriar oe vol. In a monolithicallyintegrated gaas ring laser, the value k. Shkel defense advanced research project agency darpa, usa 08. Superluminal raman laser with enhanced cavity length sensitivity. Qu t, yang k, han x, wu s, huang y and luo h 2014 design of a superluminal ring laser gyroscope using multilayer optical coatings with huge group delay nat. They are widely used for process and quality control i a laser surface velocimeter lsv is a noncontact optical speed sensor measuring velocity and length on moving surfaces. The ring laser also can detect the sidereal day, which can also be termed mode 1. These include, for example, atomic interferometers and superluminal ring lasers.
From large to small the hierarchy of gyroscope sensors can be listed as ring laser gyroscope, fiberoptic gyroscope, fluid gyroscope, and vibration gyroscope. Design of a superluminal ring laser gyroscope using multilayer optical coatings with huge group delay article pdf available in scientific reports 4. In section 7, we outline an explicit scheme for realizing fastlight enhanced gyroscope, and present numerical estimates for the prospect of measuring the lensthirring rotation using such a gyroscope. Enhancement of the sagnac effect due to nonlinearly induced nonreciprocity. Superluminal ring laser for hypersensitive sensing. The principle of using light to measure changes in direction are based on research by french scientist georges sagnac. Inertial navigation is a selfcontained navigation technique in which measurements provided by accelerometers and gyroscopes are used to track the position and orientation of an object relative to a known starting. Active application number us15984,048 inventor jeanclaude diels ladan arissian. Its digital io enables integration into almost any system, which is illustrated by its use in a. Fiberoptic gyroscope technology and ring laser gyroscope technology. A standard specification format guide for the preparation of a singleaxis rlg is provided. This gd assisted superluminal rlg can measure the absolute rotation.
We propose and analyze a superluminal ring laser gyroscope rlg using multilayer optical coatings with huge group delay gd. Modern sagnac gyroscopes either use a coil of fiberoptic cable to make the path length around a ring interferometer very long several km or use a ring laser cavity, which results in a frequency shift between the light propagating. Fast light, however, can be used to increase gyro sensitivity without having to increase size, for spacecraft navigation systems which are constrained by weight and volume. A wlc is a cavity which resonates over a broader range of frequencies than ordinary empty. Gyroscopes are also available in different sizes with different performances. By fitting the experiment data with the theoretical model, we infer that the spectral sensitivity of the superluminal raman laser to cavity length change is enhanced by a factor of more than a. This is followed by the development of a novel data buffering system which employs two wlc systems in series. A compilation of recommended procedures for testing an rlg, derived from those presently. This gd assisted superluminal rlg can measure the absolute rotation with a giant sensitivityenhancement factor of 10 3. Superluminal ring laser for hypersensitive sensing semantic scholar. In recent years, significant progress has been made in developing new technologies that can potentially yield performance parameters that would meet the most stringent requirements. The mirrors are labeled as m 11,m 12,m,m 2,m 21,m 22,m 23,m 24, and m 3, while m 11 is used for the output. Based on their sizes, gyroscope sensors are divided as small and largesized. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.
A ring laser gyroscope rlg consists of a ring laser having two independent counterpropagating resonant modes over the same path. Osa white light cavity formation and superluminal lasing. Us10317212b1 us15984,048 us201815984048a us10317212b1 us 10317212 b1 us10317212 b1 us 10317212b1 us 201815984048 a us201815984048 a us 201815984048a us 10317212 b1 us10317212 b1 us 10317212b1 authority us united states prior art keywords laser system cavity pulses resonant element prior art date 20170519 legal status the legal status is an assumption and. Inside a laser, however, the gain is constant, equaling the loss. Are the new mems gyros accurate enough to detect and. Special session i a1la highperformance gyroscope technologies 08. Ultrahigh enhancement in absolute and relative rotation.
Design of a superluminal ring laser gyroscope using multilayer optical coatings with huge group delay. Ring laser gyroscopes are extremely sensitive to rotations, which need to be accounted for if an inertial guidance system is to return accurate results. Passive optical gyroscope with double homodyne readout. These applications are all based onsocalled the white light cavity wlc. Compact, fiberbased, fastlight enhanced optical gyroscope. Superluminal effects have many potential applications, ranging from optical data buffers to sensitivityenhanced interferometers 1,2,3. The major concept was to introduce a laser cavity into the light path, in order to increase the strength of the sagnac e. A superluminal heliumneon ring laser the scheme of a superluminal hene ring laser, similar to that in 7, is shown in. This is known as the superluminal or the fastlight regime, since the group velocity exceeds the speed of light in vacuum. Practical considerations on the multilayer mirrors for. Table of contents monday, november 1, 2010 keynote presentation 1 a1ka1 cyborg beetles.
Slowfast light based on stimulate brillouin scattering sbs has become an effective way to engineer the group index 17,18. It is also possible to detect the gravitational framedragging effect by measuring the lensethirring rotation on the earth 6. Improving optical gyroscope sensitivity using a fast light. Superluminal ring laser gyroscopes and accelerometers for hypersensitive and compact inertial measurement units, selim m. Sensitivity enhancement of ring laser gyroscope using. Superluminal ring laser for gyroscopes, accelerometers, and magnetometers static and dynamic holographic memory and correlator polarimetric laser radar and optical coherence tomography atominterferometric rotation sensing gravitational wave detection atomic clock for gps applications nanolithography using bec. Pdf practical considerations on the multilayer mirrors for. In particular, a dip in the gain profile leads to a. A laser operates by exciting atoms in plasma to release electromagnetic energy, or photons. Laser surface velocimeters use the laser doppler principle to evaluate the laser light scattered back from a moving object. The invention disclosed here uses lasers operating at different frequencies. The effect of broadened linewidth induced by dispersion on. The implications of these findings on the sensitivity of sensors based on these lasers are discussed in details.
In this work, a superluminal hene ring laser with a zeroarea auxiliary cavity is proposed in detail. The idea of using gd coatings as a fastlight medium will shed lights on the design and application of fastlight sensors. This device is mounted on one of the internal walls of a high rise building. Ieee sensors 2010 conference preliminary program monday. It operates on the principle of sagnac effect which shifts the nulls of the internal standing wave pattern in response to angular rotation. The group velocity of light becomes superluminal in a medium. Specification and test requirements for a singleaxis ring laser gyro rlg for use as a sensor in attitude control systems, angular displacement measuring systems, and angular rate measuring systems are defined. One important application is the superluminal ring laser gyroscope 4,5, which may enable purely selfcontained navigation. Fastlight in a photorefractive crystal for gravitational. Laser surface velocimeter wikimili, the free encyclopedia.
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