摘要:
The general field of the invention is that of gyrolasers comprising at least one ring-shaped optical cavity comprising at least three mirrors, a solid state amplifying medium pumped by a laser diode whose optical emission power is determined by a current supply source, the cavity and the amplifying medium being such that two so-called contra-rotating optical modes propagate in opposite directions to each other within the said optical cavity, the gyrolaser being a class B gyrolaser, the gyrolaser also comprising means of measuring the difference in optical frequency existing between the two optical modes. The gyrolaser comprises means of measuring the total optical power circulating in the optical cavity and first means of control of the current delivered by the supply source in such a way as to maintain the total optical power substantially constant in a narrow spectral band centred on the relaxation frequency of the laser.
摘要:
The field of the invention is that of solid-state laser gyros used for the measurements of rotation speed or relative angular positions. This type of equipment is notably used for aeronautical applications. The object of the invention is to complete the optical devices necessary to control the instability of lasers by specific optical devices enabling elimination of the dead zone and of population inversion gratings exiting in the amplifying medium. An “all optical” solid-state laser is hence obtained without moveable parts, stable and without a dead zone. To this end, the laser gyro according to the invention comprises notably and optical assembly enabling a nonreciprocal optical phase-shift to be introduced between the counterpropagating modes; and control means allowing the phase-shift amplitude to be varied periodically around a mean value that is very approximately zero.
摘要:
The field of the invention is that of solid-state ring lasers or laser gyros. The laser gyro according to the invention comprises at least one optical cavity in the form of a ring and a solid-state amplifying medium which are designed so that two counterpropagating optical modes can propagate in opposite directions one with respect to the other inside said optical cavity and pass through the amplifying medium, said amplifying medium being coupled to an electromechanical device imparting on said amplifying medium a periodic translational movement along an axis substantially parallel to the direction of propagation of said optical modes. Thus, the population inversion grating, written by the standing wave into the amplifying medium, which disturbs the nominal operation of the laser gyro, is greatly attenuated.
摘要:
The field of the invention is that of solid-state ring lasers or laser gyros. The laser gyro according to the invention comprises at least one optical cavity in the form of a ring and a solid-state amplifying medium which are designed so that two counterpropagating optical modes can propagate in opposite directions one with respect to the other inside said optical cavity and pass through the amplifying medium, said amplifying medium being coupled to an electromechanical device imparting on said amplifying medium a periodic translational movement along an axis substantially parallel to the direction of propagation of said optical modes. Thus, the population inversion grating, written by the standing wave into the amplifying medium, which disturbs the nominal operation of the laser gyro, is greatly attenuated.
摘要:
The field of the invention is that of solid-state laser gyros used in inertial control units. However, there are certain technical difficulties in producing laser gyros of this type that are due partly to the fact that the counterpropagating waves interfere with each other in the amplifying medium. A laser gyro according to the invention comprises at least one solid-state amplifying medium and an optical ring cavity comprising first optical means for imposing a first linear polarization state common to the two counterpropagating optical waves at the entrance and exit of the zone containing the amplifying medium and second optical means for imposing, within the amplifying medium, a second linear polarization state on the first optical wave and a third linear polarization state on the second optical wave, these polarization states being perpendicular. Thus, all the drawbacks associated with interference are eliminated.
摘要:
The field of the invention is that of solid-state laser gyros. One of the major inherent problems in this technology is that the optical emission of this type of laser is by nature highly unstable in terms of power. To reduce this instability, the invention proposes to introduce, into the cavity, optical gains controlled by the installation of an optical assembly comprising an anisotropic lasing medium, a first optical element and a second optical element exhibiting a nonreciprocal effect, each acting on the polarization of the counterpropagating optical modes, at least one of these two effects being variable, thus making it possible to introduce controlled optical gains that depend on the propagation direction of the counterpropagating optical modes. Several devices are described and employ either fixed effects of the element that are combined with variable nonreciprocal effects, or the reverse. These devices apply in particular to monolithic-cavity lasers.
摘要:
The invention concerns solid-state gyrolasers used to measure rotation speeds or relative angular positions. This type of equipment is used, in particular, in aeronautical applications. The purpose of the invention is to complete the optic devices required to control the instability of lasers, using specific optic devices that eliminate the blind region. In this way, a “fully optic” solid-state laser is obtained, without moving parts, stable, and without blind regions. These devices comprise in particular reciprocal and nonreciprocal optical rotators, arranged so that two counter-propagating optical modes travel in the cavity at sufficiently different frequencies to avoid mode locking.
摘要:
A laser gyro for measuring the angular velocity or the angular position relative to a defined rotation axis includes: an optical ring cavity; a solid-state amplifying medium; and a non-reciprocal magneto-optic device; which are arranged so that four linearly polarized propagation modes can propagate within the cavity, the magneto-optic device introducing a frequency bias between the modes propagating in a first direction and the modes propagating in the opposite direction. In the device, the cavity also includes a stabilizer device for stabilizing the intensity of the four propagation modes at substantially equivalent levels, said device comprising at least one optical element made of a non-linear crystal of the frequency-doubling type.
摘要:
Solid-state gyrolaser having a device for stabilizing the intensities making it possible to maintain equilibrium of the two counter-propagating modes having at least a means for calculating a rotation measurement (Ω, IΩ) of the gyrolaser on the basis of the counter-propagating modes having a frequency difference (Δνmes) between them, by assuming that the frequency difference (Δνmes) between the two counter-propagating modes is induced only by the rotation of the cavity. The gyrolaser also includes a means for measuring the control command (Co), a means for storing a behaviour model (Mo) of a frequency bias (Δνb) induced by the device for stabilizing the intensities, as a function of the control command, a means for calculating the frequency bias (Δνb) induced by the device for stabilizing the intensities, on the basis of the value of the control command (Co) and the model (Mo), a means for calculating the bias (ΔΩb, ΔIΩb) in the rotation measurement (Ω, IΩ), induced by the frequency bias (Δνb), and a means for compensating for the bias (ΔΩb, ΔIΩb) in the rotation measurement (Ω, IΩ).
摘要:
The field of the invention is that of solid-state laser gyros used in inertial control units. However, there are certain technical difficulties in producing laser gyros of this type that are due partly to the fact that the counterpropagating waves interfere with each other in the amplifying medium. A laser gyro according to the invention comprises at least one solid-state amplifying medium and an optical ring cavity comprising first optical means for imposing a first linear polarization state common to the two counterpropagating optical waves at the entrance and exit of the zone containing the amplifying medium and second optical means for imposing, within the amplifying medium, a second linear polarization state on the first optical wave and a third linear polarization state on the second optical wave, these polarization states being perpendicular. Thus, all the drawbacks associated with interference are eliminated.