Optical pulse sources. In one example, the pulse source includes an optical fiber ring resonator with at least one normal dispersion fiber segment characterized by a positive group velocity dispersion (GVD) per unit length and at least one anomalous dispersion fiber segment characterized by a negative GVD per unit length. In another example, the pulse source includes an optical fiber ring resonator with one or more fiber segments having a positive net group velocity dispersion (GVD); and an intracavity spectral filter optically coupled to the one or more fiber segments. The pulse source is configured to generate one or more optical solitons in the optical fiber ring resonator.

A method and a system for pulsed excitation of a nonlinear medium for photon pair generation, he method comprising exciting a single narrow resonance of a nonlinear resonant element with a pulsed laser field, comprising embedding a nonlinear resonant element directly into an external laser cavity and locking the cavity modes.

The present invention provides a repetition frequency-tunable optical frequency comb generated by basis of optical feedback. The optical frequency comb comprises a single-frequency laser resonant cavity, a wavelength division multiplexer, a single-mode semiconductor pump light source, an optical circulator, a first optical fiber coupler, a second optical fiber coupler, a photoelectric detector, a highly-stable signal source, an error signal processing system, a laser frequency modulation device and a tunable laser-delay module. The present invention performs delay-time processing to the single-frequency laser by the tunable laser-delay module, and achieves an optical feedback by the optical circulator for injecting to the resonant cavity, generating a series of tunable laser longitudinal modes with equal frequency space. Meanwhile, in combination with the highly-stable signal source, the error signal processing system and the laser frequency modulation device, a laser frequency lock is achieved, and the laser frequency comb is generated. The invention obtains a repetition frequency-tunable laser frequency comb with a simple and practical method, having an extensive application prospect and huge application value in fields such as optical fiber sensing and spectroscopy of atom and molecule.

A pumped optical ring laser sensor such as a gyroscope includes a pulsed laser source to generate optical pump pulses and a synchronously pumped ring laser. The ring laser is optically pumped by first optical pump pulses from the pulsed laser source that are directed in a clock-wise (CW) direction through the ring laser and by second optical pump pulses from the pulsed laser source that are directed in a counter-clock wise (CCW) direction through the ring laser. The ring laser has an optical resonator that includes a gain medium for producing CW and CCW frequency-shifted pulses from the first and second optical pump pulses. The ring laser further includes a port for receiving the first and second pump pulses and for extracting the CW and CCW frequency-shifted pulses from the ring laser such that the frequency-shifted pulses overlap in time after being extracted to generate a beatnote.

An optical coherence analysis system uses a laser swept source that is constrained to operate in a mode locked condition. This is accomplished by synchronously changing the laser cavity's gain and/or phase based on the round trip travel time of light in the cavity. Many high-speed wavelength swept laser sources emit pulses synchronized with the round trip time of the cavity as part of a nonlinear optical frequency red shifting process. Stable pulsation is associated with smooth tuning and low relative intensity noise. Addition of mode-locking methods to this class of lasers can control and stabilize these lasers to a low clock jitter and RIN state, and in specific cases allow long-to-short wavelength tuning in addition to the usual short-to-long (red shifting). The laser may comprise a SOA (410), a tunable Fabry-Perot-Filter (412) as one reflector and an Output coupler (405) in an optical fiber (406) to adjust the cavity length.

A single mode fiber pulsed oscillator includes an all normal dispersion ring cavity provided with a mode-locking fiber loop component and a giant chirp generating fiber component. The mode-locking fiber loop component is configured with a hybrid of NOLM and NALM configurations which is operative to induce a first phase acquisition of a spectrally narrow pulse due to SPM. The giant chirp generating fiber loop component is configured to induce the additional phase acquisition to the pulse broadened in the mode-locking fiber component so as to generate a pulse with a giant chirp. The fiber loop components each include a fiber amplifier and a coil of fiber. The amplifiers each are configured with an active fiber provided with a core which supports multiple transverse mode in a range of wavelength except for the desired wavelength at which the core is configured to support a single fundamental mode.

Methods, systems and apparatus are disclosed for delivery of pulsed treatment radiation by employing a pump radiation source generating picosecond pulses at a first wavelength, and a frequency-shifting resonator having a lasing medium and resonant cavity configured to receive the picosecond pulses from the pump source at the first wavelength and to emit radiation at a second wavelength in response thereto, wherein the resonant cavity of the frequency-shifting resonator has a round trip time shorter than the duration of the picosecond pulses generated by the pump radiation source. Methods, systems and apparatus are also disclosed for providing beam uniformity and a sub-harmonic resonator.

Apparatuses and methods are disclosed for applying laser energy having desired pulse characteristics, including a sufficiently short duration and/or a sufficiently high energy for the photomechanical treatment of skin pigmentations and pigmented lesions, both naturally-occurring (e.g., birthmarks), as well as artificial (e.g., tattoos). The laser energy may be generated with an apparatus having a resonator with the capability of switching between a modelocked pulse operating mode and an amplification operating mode. The operating modes are carried out through the application of a time-dependent bias voltage, having waveforms as described herein, to an electro-optical device positioned along the optical axis of the resonator.

A method for generating stabilized, pulsed laser radiation is disclosed, the method including at least the steps of generating pulsed laser radiation at a repetition frequency, wherein the spectrum of the pulsed laser radiation is a frequency comb having a number of equidistant spectral lines; deriving a first controlled variable from the pulsed laser radiation by means of phase comparison with a high-frequency reference signal; generating narrow-band continuous-wave laser radiation at a reference wavelength; setting the reference wavelength in accordance with a first manipulated variable derived from the first controlled variable; deriving a second controlled variable by means of superposition of the pulsed laser radiation and the continuous-wave laser radiation; and setting the repetition frequency in accordance with a second manipulated variable derived from the second controlled variable. A device for generating stabilized, pulsed laser radiation compatible with the method is also disclosed.

A mode-locked laser (MLL) that produces ultra-low phase noise optical and RF outputs, includes two nested resonant optical cavities including an optical fiber-based cavity and an etalon, and a three bandwidth Pound-Drever-Hall (PDH) frequency stabilizer assembly incorporating three different optical bandpass filters. The optical fiber-based cavity is characterized by a free spectral range, FSR.sub.fiber, and the etalon is characterized by a free spectral range, FSR.sub.filter, wherein FSR.sub.filter/FSR.sub.fiber is an integer equal to or greater than 2. A method of generating ultra-low phase noise optical and RF outputs is disclosed. Optical and RF outputs have a phase noise that is less than 100 dBc/Hz at 1 Hz and less than 150 dBc at 10 KHz.