A planar optical resonator capable of parametrically generating frequency combs includes two optical waveguide cores forming inner and outer loops, the resonator having two sections, in which laterally adjacent segments of the cores are resonantly optically coupled to each other at two separate wavelength regions causing separate peaks in the second order dispersion. The resonator sections may be configured to suppress integrated dispersion of the resonator in a broad spectral range favorably for generating a spectrally uniform frequency comb.

This invention disclosed a system and method for characteristics measurement of electromagnetic signals. The measurement system comprises a multi-repetition-rate pulsed light source, a frequency mixer for electrical signal and optical signal, and a data acquisition and processing device. The measurement system accurately determines the characteristic information of the signal to be measured, such as frequency, phase, intensity, and their variations, by measuring the low frequency mixed signal generated by the multi-repetition-rate pulsed light source and the signal to be measured in the frequency mixer. This system has the advantages of simple structure, high measurement accuracy, low cost and large measurable frequency range. The system can be applied to the measurement of various electromagnetic signals, covering the spectral range from microwave, millimeter wave, to terahertz and even light wave.

A method and apparatus for enhancing the stability of an oscillator circuit by generating a comb of frequencies in a non-linear resonator member in response to a drive frequency, the oscillator circuit including a voltage controlled oscillator which is locked to a particular tooth of the comb of frequencies produced by the non-linear resonator member at a drive frequency for which the absolute value of the first derivative of the drive frequency versus said comb frequency is greater than 1, and wherein the second voltage controlled oscillator is coupled with a phase locked loop circuit which controls the locking of the second voltage controlled oscillator to said particular tooth of the comb of frequencies.

The present application relates to a mid-infrared (MIR) optical frequency comb (OFC) generation system and method based on manipulation of the multi-photon absorption (MPA) effect, which can break through the repetition-rate limitation for traditional systems and restricted bandwidth as well as high dependence on high-performance pump sources for microcavity-based frequency combs. The system includes a pump light source unit for providing a pump laser, a microring resonator (MRR) unit for broadband comb generation through nonlinear four-wave-mixing process, and an MPA effect control unit for realizing the MIR soliton-state OFC by controlling the loaded voltage or current on the MRR unit. The proposed system and operation method have advantages of being simple in structure, economic for use, and easy to implement for broadband low-noise frequency comb generation.

One aspect of the present disclosure relates to a medical laser system, comprising: a first laser source comprising at least a first gain medium for generating a first optical field; and at least one first U-switch configured to control a resonance quality of the first laser source; a control circuit configured to control the first U-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; at least one nonlinear medium for generating a third optical field by a nonlinear interaction between the first optical field and the second optical field; a sensor configured to detect a property of at least one of the optical fields; wherein the control circuit is configured to control operation of the first U-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.

Laser systems are described that each include at least one excitation laser, a high frequency laser pulse source, and a beam switchover device. The beam switchover device is configured to be switched, in order a) in a high-frequency functional position to guide at least one GHz laser pulse train with a pulse repetition rate of individual pulses in the GHz laser pulse train of at least 0.5 GHz from the high frequency laser pulse source to a target position, and b) in a low-frequency functional position to guide at least one low-frequency laser pulse train with a pulse repetition rate of individual pulses in the low-frequency laser pulse train of less than 0.5 GHz from the at least one excitation laser to the target position.

Various technologies described herein pertain to multiple laser, single optical resonator lidar systems. A lidar system includes a single optical resonator optically coupled to at least a first laser and a second laser. The optical resonator is formed of an electrooptic material. The first laser and the second laser are optically injection locked to the optical resonator. Moreover, a modulator applies a time-varying voltage to the optical resonator to control modulation of an optical property of the electrooptic material, which causes the first laser to generate a first frequency modulated optical signal comprising a first series of optical chirps and/or the second laser to generate a second frequency modulated optical signal comprising a second series of optical chirps. Further, front end optics transmits at least a portion of the first frequency modulated optical signal and/or the second frequency modulated optical signal into an environment from the lidar system.

A method and apparatus for enhancing the stability of an oscillator circuit by generating a comb of frequencies in a non-linear resonator member in response to a drive frequency, the oscillator circuit including a voltage controlled oscillator which is locked to a particular tooth of the comb of frequencies produced by the non-linear resonator member at a drive frequency for which the absolute value of the first derivative of the drive frequency versus said comb frequency is greater than 1, and wherein the second voltage controlled oscillator is coupled with a phase locked loop circuit which controls the locking of the second voltage controlled oscillator to said particular tooth of the comb of frequencies.

Disclosed is a system for generating short or ultra-short light pulses, including a light source configured to emit temporally continuous-wave light radiation, an electrical generator configured to operate at a tunable frequency in a passband included between 5 and 100 GHz and to emit an analogue modulating electrical signal including at least one electrical pulse of duration included between 10 ps and 100 ps, and an electro-optical modulator having electrodes and an electrical passband that are suitable for receiving the analog modulating electrical signal, the electro-optical modulator being configured to optically amplitude modulate the continuous-wave light radiation depending of the analog modulating electrical signal and to generate modulated light radiation including at least one light pulse of duration included between 10 ps and 100 ps.

A method for generating a laser pulse train is provided, including at least the following method steps: generating a laser pulse train at a pulse repetition frequency; coupling the laser pulse train into an acousto-optical modulator, and selecting individual laser pulses of the laser pulse train. A system for generating a laser pulse train is also provided, including at least a pulsed laser and an acousto-optical modulator, and an associated control device.