To measure the frequency of a laser, the frequency of a beat signal that is generated by the interference between an optical frequency comb, used as the reference of measurement, and the laser to be measured is measured. In such a laser frequency measurement using the optical frequency comb, at least one of a repetition frequency and a CEO frequency of the optical frequency comb is changed so that the frequency of the beat signal becomes a predetermined value, and the frequency of the beat signal is measured, so that the frequency of the laser is measured. This allows measurement of the frequency of laser having large frequency variation and low stability.

A medical laser system including a first laser source having a first gain medium for generating a first optical field. The system further includes a first Q-switch controlling a resonance quality of the first laser source, a control circuit controlling the first Q-switch to cause the first laser source to generate the first optical field as a first pulse train of laser pulses, a second laser source for generating a second optical field as a second pulse train of laser pulses, a nonlinear medium for generating a third optical field by a nonlinear interaction between the first optical field and the second optical field, and a sensor detecting a property of at least one of the optical fields. The control circuit controls operation of the first Q-switch so as to adjust a relative timing of the laser pulses of the first pulse train and the laser pulses of the second pulse train responsive to the detected property.

Photonic devices for generating linearly frequency modulated arbitrary microwave signals comprise a laser, and assembly for forming the emitted signal and a photoreceiver the passband of which is in the domain of the microwave frequencies. The forming assembly comprises: a first beam splitter; a first optical channel including a frequency-shifting loop comprising a beam splitter, a first optical amplifier, an optical isolator, a first spectral optical filter and an acousto-optical frequency shifter; a second optical channel including an electro-optical frequency shifter; a second beam splitter; a second optical amplifier; and a second optical filter; the acousto-optical frequency shift, the electro-optical frequency shift and the amplification gain of the first optical amplifier being adjustable.

The present invention relates to an integrated circuit, in particular a photonic integrated circuit, for generating an electrical and/or optical frequency comb signal, the integrated circuit comprising: a pulse generation unit comprising an input port for receiving an optical high frequency signal. The present invention provides a Kerr-ring for the generation of an optical frequency comb signal. The use of the Kerr-ring for the optical frequency comb generation makes the integration possible. The present invention further relates to an optical system and a test and measurement device.

To measure the frequency of a laser, the frequency of a beat signal that is generated by the interference between an optical frequency comb, used as the reference of measurement, and the laser to be measured is measured. In such a laser frequency measurement using the optical frequency comb, at least one of a repetition frequency and a CEO frequency of the optical frequency comb is changed so that the frequency of the beat signal becomes a predetermined value, and the frequency of the beat signal is measured, so that the frequency of the laser is measured. This allows measurement of the frequency of laser having large frequency variation and low stability.

To measure the frequency of a laser, the frequency of a beat signal that is generated by the interference between an optical frequency comb, used as the reference of measurement, and the laser to be measured is measured. In such a laser frequency measurement using the optical frequency comb, at least one of a repetition frequency and a CEO frequency of the optical frequency comb is changed so that the frequency of the beat signal becomes a predetermined value, and the frequency of the beat signal is measured, so that the frequency of the laser is measured. This allows measurement of the frequency of laser having large frequency variation and low stability.

An optical pulse train generation device includes a storage unit and a characteristic setting unit. The storage unit stores a plurality of phase patterns in advance. The plurality of phase patterns are phase patterns for forming, from a first optical pulse, an optical pulse train including a plurality of second optical pulses having time differences therebetween and having different center wavelengths. Between the plurality of phase patterns, one or both of a first characteristic regarding the first optical pulse and a second characteristic regarding the optical pulse train are different. The characteristic setting unit sets the first characteristic and the second characteristic in response to the user's input. The storage unit stores the plurality of phase patterns in association with the first characteristic and the second characteristic. A spatial light modulator displays a phase pattern corresponding to the first characteristic and the second characteristic set by the characteristic setting unit.

The invention relates to a method for generating a laser pulse train, comprising the following method steps: generating the laser pulse train (4a) at a pulse repetition frequency; coupling the laser pulse train (4a) into an acousto-optical modulator, and selecting individual laser pulses of the laser pulse train (4a) by driving the acousto-optical modulator with high-frequency pulses (4h), wherein the high-frequency pulses (4h) are generated by modulating a high-frequency carrier signal (4f) with a periodic switching signal (4e). In addition, the invention relates to a system for generating a laser pulse train, comprising a pulsed laser (1), which generates the laser pulse train at a pulse repetition frequency, and an acousto-optical modulator (2), in which the laser pulses propagate, and comprising a control device (7), which drives the acousto-optical modulator (2) with high-frequency pulses for the purpose of selecting individual laser pulses. It is an object of the invention to provide an improved method for selecting individual laser pulses from a laser pulse train. The intensity noise known from the prior art is intended to be reduced. The invention achieves this object by virtue of the fact that the following holds true for the frequency f.sub.HF of the carrier signal (4f) of the high-frequency pulses (4h): f.sub.HF=n/p.Math.f.sub.PRF, wherein n is an arbitrary natural number and p indicates the integral ratio between the pulse repetition frequency and the frequency of the switching signal (4e), and wherein the carrier signal (4f) is coupled to the laser pulse train (4a) in a phase-stable manner.

The present invention provides a low-loss high-repetition-rate pulsed laser modulator comprising: a 2*2, 1:1 coupler; a light delay module; a 1*2, 1:1 coupler. The present invention can modulate a low-repetition-rate pulsed laser to be a high-repetition-rate pulsed laser. The basic principle is: one beam of low-repetition-rate pulsed laser can be divided into two beams with the same light intensity by a 1*2, 1:1 coupler; control the two beams of light to have an optical path difference so that when they are coupled into a 2*2, 1:1 coupler, a double pulse repetition rate can be obtained; In the same way, when the two beams of light from former 2*2, 1:1 coupler, with another different optical path difference are coupled into the next 2*2, 1:1 coupler, a double pulse repetition rate can be obtained again; when we obtain the repetition rate we need, a 1*2, 1:1 coupler instead is connected to couple the two beams of light into one beam with a double repetition rate.

The present invention provides a low-loss high-repetition-rate pulsed laser modulator comprising: a 2*2, 1:1 coupler; a light delay module; a 1*2, 1:1 coupler. The present invention can modulate a low-repetition-rate pulsed laser to be a high-repetition-rate pulsed laser. The basic principle is: one beam of low-repetition-rate pulsed laser can be divided into two beams with the same light intensity by a 1*2, 1:1 coupler; control the two beams of light to have an optical path difference so that when they are coupled into a 2*2, 1:1 coupler, a double pulse repetition rate can be obtained; In the same way, when the two beams of light from former 2*2, 1:1 coupler, with another different optical path difference are coupled into the next 2*2, 1:1 coupler, a double pulse repetition rate can be obtained again; when we obtain the repetition rate we need, a 1*2, 1:1 coupler instead is connected to couple the two beams of light into one beam with a double repetition rate.