Abstract: The present invention provides a wavelength-tunable laser apparatus which is capable of obtaining a high output while suppressing the generation of spontaneous emission, as well as having a broad wavelength-tunable range.

Abstract: Laser type source of coherent luminous radiation including a resonant cavity, an amplification medium placed in the resonant cavity and a dynamic photosensitive material which is placed in the resonant cavity to form a self-adapting spectral and/or spatial filter, characterized in that the cavity is a ring laser cavity and in that the dynamic photosensitive material is placed at the intersection of two beams.

Abstract: A gas drawing/refilling and sealing structure for a laser gas storage container of the present invention includes a sealed container and a blocking member, wherein the body of the container is provided with a gas passage having a gas inlet end and a blocking end. The gas passage is further provided with a communicating section to make connection of the gas passage to the container. The blocking member is mounted on the blocking end, gas is drawn out of or injected into the container via the gas inlet end when the gas inlet end is opened; the gas is cut off when the gas inlet end is closed, and the container is sealed at the same time. Thereby, manufacturing and test of the laser equipment can be more convenient, and the superiority of products can be increased.

Abstract: The method and system operate to maintain a widely tunable laser (WTL) at a selected transmission wavelength. To lock the WTL to an ITU grid line, a portion of the output beam from the WTL is routed through the etalon to split the beam into a transmission line for detection by an etalon fringe detector. Another portion of the beam is routed directly to a laser wavelength detector to determine the power of the beam. A wavelength-locking controller compares signals from the two detectors and adjusts the temperature of the etalon to align the wavelength of one of the transmission lines of the etalon with the wavelength of the output beam, then controls the WTL in a feedback loop to lock the laser to the etalon line. The wavelength-locking controller thereafter monitors the temperature of the etalon and keeps the temperature constant to prevent any wavelength drift attributable to the etalon.

Abstract: Photonic arbitrary waveform methods and generation by manipulating the phase-locked longitudinal modes of an approximately 12.4 GHz fundamentally modelocked external-cavity semiconductor laser are demonstrated. Photonically synthesized sine waves (center frequency of approximately 37.2 GHz, linewidth less than approximately 100 Hz, dynamic range approximately 50 dB at approximately 100 Hz resolution bandwidth) and complex, arbitrarily shaped optical/microwave frequency waveforms with instantaneous bandwidths up to approximately 75 GHz are shown. A WDM filter can be used to separate individual longitudinal modes of a modelocked laser. Photonic arbitrary generation occurs through the modulation of individual channels before recombining the channels, followed by amplifying the output.

Abstract: A method for tuning a laser via a temperature control loop that linearizes a non-linear characteristic of a thermal electric cooler (TEC) element used to adjust the temperature of tuning components and corresponding laser apparatus. One or more TEC elements are thermally coupled to respective tuning components, such as etalon filters. The TEC elements provide a heat transfer function (cooling rate) in response to a received electrical input (drive signal), wherein the relationship between the cooling rate and the drive signal is non-linear. An un-compensated drive signal produced by the control loop is compensated such that the open loop gain of the control loop is linearized via a linearizer control block. In effect, the non-linear transfer function of the TEC element is cancelled out by the linearizer control block to produce a linear relationship between the cooling rate and the drive signal.

Abstract: The present invention discloses a novel apparatus and method for stabilizing the frequency of a laser. To avoid the effect that a single-frequency absorption spectrum is easy to be affected by variations of laser power and the complexity to modulate a laser frequency, the present invention adopts at least two laser beams at different frequencies and obtains an error signal that is a difference in absorption spectrums of the laser beams. Since the error signal is a difference between two laser beams coming from an identical laser source, the variation of laser power could be eliminated. Furthermore, since the absorption spectrum is usually above hundreds of (MHz), the range of locked frequency of the present invention is large, and the laser frequency is not easily unlocked due to outside disturbance.

Abstract: A method for selecting free spectral ranges (FSR) of intra-cavity optics to optimize reliability of the channel switching mechanism and corresponding apparatus. In particular, the optimal relationship between the FSR of the internal etalon and the FSR of the laser cavity is derived. For the external cavity diode lasers (ECDL) the optimal relationship between the FSR of the internal etalon and the FSR of the gain chip is also derived. Equations are derived for selecting free spectral ranges of various optical cavities so as to create a locally commensurate condition under which the relative position of the lasing mode with respect to the transmission peak of the laser's tunable filter (e.g., etalon plus channel selector) does not change when the laser hops between adjacent channels.

Abstract: Apparatus and method for controlling the length of a laser cavity comprises a laser diode that is configured to produce a beam of energy, the laser diode has a first end and an output end, the first end being in optical communication with a highly reflective mirror. A wave guide having a receiving end and a transmission end is also provided, with the wave guide being comprised of an electro-optical material, wherein the receiving end is in optical communication with the output end, and the transmission end is in optical communication with an output coupler. A plurality of electrodes are disposed along a longitudinal axis of the wave guide, wherein the voltage on each electrode is independently controlled to alter the index of refraction of the wave guide at a position adjacent each electrode. A polarizer is also provided with respect to the transmission end, with the polarizer configured to attenuate the beam of energy.

Abstract: A spiral-type guide member having a spiral channel extending about an open center portion is provided adjacent the gas inlet end of the laser discharge tube of a gas laser assembly. This guides the entering gas stream about the periphery of the laser discharge tube to improve the distribution of the power of the laser beam over the cross section of the laser discharge tube to the discharge tube of the laser beam 113 is provided for the laser gas in the feed line 123, through which at least part of the laser gas is fed to the laser-discharge tube 103.

Abstract: An optically-pumped semiconductor (OPS) laser includes a multilayer structure including a mirror-structure surmounted by a multilayer semiconductor gain-structure. A membrane mirror is spaced apart from the mirror structure to form a laser resonator between the mirror structure and the membrane mirror, with the gain-structure included in the laser resonant cavity. Pump light is transmitted through the membrane mirror into the gain structure. The membrane mirror includes a grating having parameters selected such that the membrane mirror has different reflectivities at the wavelength of the laser in two orthogonally-oriented planes of polarization. The membrane mirror is axially movable along the resonator axis for varying the resonator length to select the wavelength of the single lasing mode.

Abstract: Method and apparatus for producing a laser output having stimulated Brillouin scattering (SBS) suppression characteristics. An excitation signal is provided to an optical path length adjustment element in an external cavity laser to modulate the optical path length of the cavity. This produces a laser output having a wavelength modulation frequency and line width that are a function of the frequency and amplitude of the excitation signal. Under appropriate modulation frequency and line width combinations, the laser output comprises an optical signal with SBS suppression characteristics, thus enabling a higher power signal to be launched into a fiber link since the SBS suppression characteristics raise the SBS threshold of the link. The optical path length modulation also produces an intensity (amplitude) modulation in the laser output. A detector is employed to produce a feedback signal indicative of the intensity modulation that is used for tuning the laser in accordance with a wavelength locking servo loop.

Abstract: A servo technique for concurrently providing wavelength locking and stimulated Brillouin scattering (SBS) suppression in an external cavity laser. Respective wavelength locking and SBS suppression signals are generated by a controller and combined into a composite drive signal. The composite drive signal is used to drive an optical path length adjustment element to modulate the optical path length of the laser cavity. The wavelength locking and SBS suppression portions of the drive signals produce concurrent modulations of the laser optical path length having different modulation frequencies and causing different frequency (wavelength) excursions. These modulations produce corresponding wavelength and intensity amplitude modulations in the laser's output. A feedback signal indicative of the intensity amplitude modulations is filtered to attenuate the portion of the signal due to the SBS suppression modulation, and is received as a tuning feedback signal by the controller.

Abstract: A method of wavelength locking and mode monitoring a tuneable laser that includes two or more tuneable sections in which injected current can be varied, including at least one reflector section and one phase section. Laser operation points are determined as different current combinations through the different laser sections, and the laser operates at a predetermined operation point. The wavelength of light emitted by the laser is detected by a wavelength selective filter. The laser is controlled in an iterative process in which alternated currents through the reflector section and, when applicable, its coupler section, and the current through the phase section are adjusted. The currents through the reflector section and the coupler section are adjusted to obtain a minimum ratio between power rearwards and power forwards. The current through the phase section is adjusted to hold the wavelength constant, the wavelength being measured against a wavelength reference.

Abstract: A system for producing singlet delta oxygen has a source of liquid oxygen. A reactor has an input connected to the source of liquid oxygen. An optical pump is connected to an optical input of the reactor. The system can be by used as a laser by placing an optical resonator and a source of molecular iodine near the output of the reactor.

Abstract: Techniques for stabilizing a laser at a selectable frequency include splitting an output beam from an electrically adjustable laser into a first beam and a second beam. The second beam is transmitted through a modulator. Then the second beam is transmitted through a transient spectral hole burning material onto a detector. The laser is electronically adjusted in response to a detector output from the detector which senses the changes in the modulated second beam after it passes through the transient spectral hole burning material.

Abstract: An up-conversion laser unit in which a semiconductor laser of high output power can be used as a pump light source and the wavelength of up-converted laser light is suitable for display. The light of infrared wavelength is generated by the pump light source, the generated light being inputted into a Pr3+ up-conversion laser to up-convert there into red light by Pr3+ ion. The up-converted red light is inputted into, as a pump light source, a Tm3+ up-conversion laser, there being up-converted into blue light by the Tm3+ ion. Thereby, efficient up-conversion into blue light is made possible.

Abstract: A bi-directional pulsed ring laser that produces bi-directional light pulses that interact in such a way that they are phase conjugated. A nonlinear substance, such as a nonlinear crystal or fluid, that has an index of refraction that is dependent upon light intensity is located near a beam waist of the laser cavity to provide a self-lensing effect. Methods for reducing dead band beyond observable limits are also provided. The increased sensitivity of the bi-directional pulsed ring laser provides application in detecting magnetic susceptibility by detecting the change in phase between the arrival times of the bi-directional pulses at a modulator and the electrical signal of the modulator to determine the change in frequency of a coil that has magnetic susceptibility.

Abstract: A mode controlling device for capturing a highly divergent, multi-mode laser beam received from a high-power broad area laser source and producing a narrow, single-mode laser beam. In one embodiment, the mode controlling device comprises a diffractive device having a nonplanar profile positioned to receive the multi-mode laser beam. The diffractive device comprises a plurality of grooves for receiving the multi-mode laser beam and diffracting light to a reflective medium, thereby creating feedback for producing a narrow, single-mode laser beam with a non-uniform intensity profile. The reflective medium may be positioned at the surface of the diffractive device; alternatively, the reflective medium may be positioned at a predetermined distance from the diffractive device.

Abstract: A narrow band excimer laser and a wavelength detecting apparatus are suitable for use as a light source of a reduction projection aligner of a semiconductor device manufacturing apparatus. In the excimer laser, the ruling direction and the beam expanding direction of a prism beam expander are made substantially coincide with each other, and a polarizing element causing selective oscillation of a linearly polarized light wave substantially parallel with the beam spreading direction of a prism beam expander is contained in a laser cavity. A window at the front or rear side of a laser chamber is disposed such that the window make a Brewster's angle with respect to the axis of the laser beam in a plane containing the beam expanding direction of the prism expander and the laser beam axis.