Generator for generating an anti-Kerr-effect modulated light signal, interferometry measuring device comprising such a generator, and method for modulating a light signal
Disclosed is a generator for generating an anti-Kerr modulated light signal, including a primary light source having four longitudinal modes or fewer and configured to generate a light signal and a modulator configured to modulate the power of the light signal by way of a square-wave or rectangular-wave control signal the duty cycle of which is less than or equal to 50%, and which are adapted such that the modulated light signal is periodic and has: —at a first point of the signal, a first power value equal to the product of its average power and a gain between 1.6 and 2.4; —at a second point of the signal, a second, non-zero power value, that is different from the first power value. Also disclosed is a modulation method and to a measuring device.
1 . A generator for generating an anti-Kerr modulated light signal, the generator comprising:
a primary laser light source having four longitudinal modes or fewer and configured to generate a light signal; and
a modulator configured to module the light signal, the modulator being configured to modulate a power of the light signal by a square-wave or rectangular-wave control signal, the duty cycle of which is lower than or equal to 50%, such that the modulated light signal is periodic and has:
at a first point of the modulated light signal, a first power value equal to the product of an average power by a gain between 1.6 and 2.4, and
at a second point of the modulated light signal, a second, non-zero power value, that is different from the first power value.
2 . The generator according to claim 1 , wherein the duty cycle of the square-wave or rectangular-wave control signal is strictly lower than 50%.
3 . The generator according to claim 1 , wherein the primary laser light source is a laser diode.
4 . The generator according to claim 1 , wherein the gain is equal to 2.
5 . The generator according to claim 1 , wherein the modulator is configured to adjust the second, non-zero power value of the modulated light signal.
6 . The generator according to claim 1 , wherein the modulator is configured to adjust the duty cycle of the square-wave or rectangular-wave control signal.
7 . The generator according to claim 1 , wherein the first power value is the maximum power value of the modulated light signal.
8 . The generator according to claim 1 , further comprising a feedback controller system producing a feedback signal representative of a difference between the first power value and an average power of the modulated light signal multiplied by the gain, the modulator being controlled by the feedback signal to maintain the first power value equal to the product of an average power by the gain.
9 . The generator according to claim 8 , wherein the feedback controller includes
a photodetector configured to receive at least part of the modulated light signal and to produce a first signal representative of the power of the modulated light signal,
a first filter configured to produce a second signal equal to the average value of the first signal multiplied by the gain,
a second filter configured to produce a third signal equal to the first power value, and
a feedback system configured to determine a difference between the second signal and the third signal and to produce the feedback signal representative of the difference between the second signal and the third signal.
10 . The generator according to claim 1 , wherein the primary laser light source further includes an integrated photodiode.
11 . The generator according to claim 1 , wherein the modulator is configured to modulate a power supply for the primary laser light source.
12 . The generator according to claim 1 , wherein the modulator is an optical modulator located downstream from the primary laser light source.
13 . An interferometric measurement device comprising:
the generator according to claim 1 .
14 . The interferometric measurement device according to claim 13 , wherein the interferometric measurement device is a fiber-optic gyroscope.
15 . A method for modulating a light signal emitted by primary light source having four longitudinal modes or fewer, the method comprising:
modulating the light signal by a square-wave or rectangular-wave control signal, the duty cycle of which is lower than or equal to 50%, such that the modulated light signal is periodic and has:
at a first point of the modulated light signal, a first power value equal to the product of an average power by a constant between 1.6 and 2.4, and
at a second point of the modulated light signal, a second power value that is different from the first power value and non-zero.
16 . The method according to claim 15 , wherein the duty cycle of the square-wave or rectangular-wave control signal is strictly lower than 50%.
17 . The method according to claim 15 , wherein the gain is equal to 2.
18 . The method according to claim 15 , wherein the modulating includes adjusting the second power value of the modulated light signal.
19 . The method according to claim 15 , wherein the modulating includes adjusting the duty cycle value of the modulated light signal.
20 . The method according to claim 15 , wherein the modulating includes feedback controlling the modulating by a feedback signal representative of the difference between the first power value and the average power of the light signal multiplied by the gain, the feedback controlling maintaining said first power value equal to the product of said average power by said gain.
21 . The method according to claim 15 , wherein the modulating includes modulating a power supply for the primary laser light source.
22 . The method according to claim 15 , wherein the modulating includes optically modulating the light signal emitted by the primary laser light source.