To appropriately change an output of laser light without deteriorating laser characteristics. A control section of a laser machining device controls, when a target output is larger than a predetermined threshold, an output of laser light by changing a driving current supplied to an excitation light source and, on the other hand, controls, when the target output is equal to or smaller than the threshold, the output of the laser light by changing a duty ratio of a Q switch while keeping the driving current supplied to the excitation light source substantially fixed.

To prevent an output decrease of laser light due to impurities formed in a Q switch. A laser machining device includes a Q-switch housing section configured by housing a Q switch and a first mirror and a wavelength converting section including a housing in which a transmission window section capable of transmitting a fundamental wave is formed, the wavelength converting section being configured by airtightly housing, with an internal space surrounded by the housing, at least a first wavelength conversion element, a second wavelength conversion element, and a second mirror. A resonator forming a resonant optical path passing through the transmission window section is configured by the first mirror in the Q-switch housing section and the second mirror in the wavelength converting section.

An amplified optical link having a fault-protection capability that is based, at least in part, on the ability to selectively and independently power up and down different groups of optical amplifiers within the link. In an example embodiment, the optical link is implemented using an optical fiber cable having an electrical power line and arrays of optical amplifiers connected between successive optical fiber segments to form a plurality of disjoint groups of parallel optical paths between the ends of the optical fiber cable. The electrical power line is operable to selectively power, as a group, the optical amplifiers of at least some of the disjoint groups. In various embodiments, different optical paths can be implemented using different respective strands of a single-core optical fiber, different respective cores of a multi-core optical fiber, and/or different respective sets of spatial modes of a multimode optical fiber.

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.

Briefly, methods and/or systems, are described for a wavelength-dispersive mode-locked fiber-ring laser, which generates an Airy beam profile for stable optical pulses.

The disclosure relates to a device for generating pulsed laser radiation, having a laser resonator which contains a laser-active medium (EDF1, EDF2), a pump light source which optically pumps the laser-active medium (EDF1, EDF2) at a pump power (P), and a mode coupling device which is intended to effect phase coupling of the modes of the laser radiation circulating in the laser resonator, so that the spectrum of the laser radiation forms a frequency comb. The disclosure also relates to a method for designing or operating such a device. The disclosure proposes that phase noise of the frequency comb, i.e. the width of spectral lines of the frequency comb, is minimized at a predetermined useful frequency by adjusting the frequency of the pump power fixed point (vfix.sub.,pump) of the frequency comb. For this purpose, at least two of the parameters pump power (P), group delay dispersion of the laser resonator, non-linearity of the laser resonator and amplification of the laser-active medium (EDF1, EDF2) are optimized in an iterative process until the pump power fixed point (vfix.sub.,pump) is set to the desired frequency and the quadratic increase in the width of the spectral lines of the frequency comb with the frequency spacing of the spectral lines from the useful frequency is simultaneously minimized. The disclosure provides a fiber-based laser device for generating an fs frequency comb with maximum passive stability and a simple and compact design at the same time. The achievable linewidths of the comb lines lie over a broad spectral range in the kHz and sub-kHz range.

This disclosed subject matter allows short pulses with high peak powers to be obtained from seed pulses generated by a gain-switched diode. The gain-switched diode provides a highly stable source for optical systems such as nonlinear microscopy. The disclosed system preserves the ability to generate pulses at arbitrary repetition rates, or even pulses on demand, which can help reduce sample damage in microscopy experiments or control deliberate damage in material processing.

A dual output semiconductor optical amplifier-based tunable fiber laser is provided that can be switched from low to high power and vice versa. The laser system uses bidirectional semiconductor optical amplifier (SOA) for amplification and hence is able to introduce a unique feature of adjustable dual/single output ports.

A detuned resonant mechanism is employed in a laser cavity to modulate in frequency the mode-locking mechanism to achieve high frequency tuning rates, exceeding MHz. The configuration of the laser is compatible with working at sweeping rates close to multiples of the cavity resonance frequency as well as with buffering for increased tuning speeds.

Apparatus and methods for altering one or more spectral, spatial, or temporal characteristics of a light-emitting device are disclosed. Generally, such apparatus may include a volume Bragg grating (VBG) element that receives input light generated by a light-emitting device, conditions one or more characteristics of the input light, and causes the light-emitting device to generate light having the one or more characteristics of the conditioned light.