Abstract: In an apparatus and method for generating high power laser radiation, the geometry of the resonant laser cavity defines a fundamental spatial or transverse cavity mode. A gain medium is disposed within the resonant cavity and an energy source energizes the gain medium within a first volume. This causes spontaneous and stimulated energy emission to propagate in the gain medium in a direction transverse to the fundamental cavity mode. The transverse emission in turn optically pumps a second volume of the gain medium about the first volume. When the intensity of the emission is sufficiently high, inversion and gain are produced in the second volume. By optimizing the geometry of the cavity such that the fundamental cavity mode is coupled to both the first and the second volumes encompassing the first pumped volume, the transversely-directed energy of the first volume which would otherwise be wasted is instead captured by the fundamental beam, improving the overall power efficiently of the laser.

Abstract: A high power laser optical amplifier system for material processing comprises multiple stage fiber amplifiers with rejection of propagating ASE buildup in and between the amplifier stages as well as elimination of SBS noise providing output powers in the range of about 10 .mu.J to about 100 .mu.J or more. The system is driven with a time varying drive signal from a modulated semiconductor laser signal source to produce an optical output allowing modification of the material while controlling its thermal sensitivity by varying pulse shapes or pulse widths supplied at a desire repetition rate via modulation of a semiconductor laser signal source to the system to precisely control the applied power application of the beam relative to the thermal sensitivity of the material to be processed. The high power fiber amplifier system has particular utility in high power applications requiring process treatment of surfaces, such as polymeric, organic, ceramic and metal surfaces, e.g.

Abstract: A symmetrical optical matrix crossconnect apparatus includes a plurality of optical switch devices with each comprising a first pair of fiber optic ports, a second pair of fiber optic ports and a reflective element. The first pair of fiber optic ports are disposed apart from one another and aligned coextensively along a first optical path. One of the first pair of fiber optic ports emits a first light beam that travels along the first optical path in free space while the remaining one of the first pair of fiber optic ports receives the first light beam. The second pair of fiber optic ports are disposed apart from one another and aligned coextensively along a second optical path. A first one of the second pair of fiber optic ports emits a second light beam that travels along the second optical path in free space while a remaining one of the second pair of fiber optic ports receives the second light beam. The first optical path and the second optical path crisscross each other at an intersection.

Abstract: A laser light source apparatus includes a compound cavity and an optical gain medium. The compound cavity includes first, second, and third optical reflection members disposed along the optical axis. The first optical reflection member has a light wavelength selectivity. At least one of the first to third optical reflection members can change its own position on an optical axis in relation to the other reflection members. Two of the first to third optical reflection members are provided opposite to each other with the optical gain medium inserted therebetween, thereby forming a laser light source. The other one optical reflection member is provided so as to form a light path for feeding laser light emitted from the laser light source back to the laser light source.

Abstract: Multiple-cavity fiber optic lasers are fabricated with high-gain fibers in low-loss, high-finesse fiber ferrule resonance cavity configurations supported in low-loss ferrule alignment fixtures developed for use in FFP filters. These lasers incorporate rare-earth doped, sensitized glass fiber as the active medium within FFP cavities. FFP lasers of this invention include those exhibiting single-frequency and/or single-polarization mode operation with wide mode separation. Lasers provided include those with short cavity lengths, where the longest of the cavities of can be less than or equal to about 10 mm in length. These FFP laser sources are fixed-frequency or discretely-tunable. Multiple-cavity configurations in which at least one of the cavities formed contains active fiber are readily formed in fiber ferrule assemblies. FFP lasers can be end-pumped using single- or double-pass pumping configuration or pump resonance cavity configurations.

Abstract: A laser diode is initially secured on a substrate, and light emission is caused from the laser diode to radiate light, which is measured by a measuring instrument. The laser diode is positioned at a position where a maximum output is obtained. Subsequently, while continuing light emission from the laser diode, light output which passes through a solid state laser oscillator element with a reflecting surface is measured with the measuring instrument, and the solid state laser oscillator element with a reflecting surface is secured to the substrate at a position where a maximum output is obtained.

Abstract: An external cavity, single mode laser has a semiconductor gain medium, such as a diode laser, and a monolithic prism assembly positioned in an external resonant cavity having a length of 10 mm or less. The monolithic prism assembly includes a transparent substrate carrying a thin film Fabry-Perot interference filter on a face which is tilted to the path of travel of the laser light in the external cavity. Translation of the monolithic prism assembly including transversely to the optical axis provides continuous mode-hop-free tuning of the laser output wavelength. The Such optical devices can be economically mass produced in advantageously small size, having reproducible spectral performance properties held within tight tolerances. Significantly advantageous applications include dense wavelength division multiplexing systems requiring tightly spaced wavelength subranges for each of multiple channels. High wavelength stability against temperature and humidity changes, etc., can be achieved.

Abstract: The device is formed on a silicon-on-insulator chip (which comprises a layer of silicon (1) separated from a substrate (3) by an insulator layer (2)) and comprises an integrated waveguide (4) formed in the silicon layer (1) and a reflective facet (6) formed in a recess in the silicon layer (1). The facet (6) is positioned to redirect light in a desired direction. The waveguide (4) and facet (6) are both formed in the silicon layer (1) so their positions can be defined by the same lithographic steps so they are automatically aligned with each other.

Abstract: A tapered rib waveguide tapering from a large, multi-mode optical waveguide to a smaller, single-mode optical waveguide, the tapered rib waveguide comprising two portions (4,5) formed of the same material: a lower portion (4) which tapers laterally from the large waveguide to the smaller waveguide and an upper portion (5) formed on the lower portion (4), which tapers to a point (or other form of termination), the dimensions of the two portions (4,5) being such that substantially all of a fundamental mode propagated in the large multi-mode waveguide is coupled to the smaller, single-mode waveguide.

Abstract: A compact optical device operating as a WDM (wavelength division multiplexing) filter is provided. The optical device includes a slab optical waveguide having first and second end faces opposed to each other, a plurality of first optical waveguides connected to the first end face of the slab optical waveguide, and a plurality of second optical waveguides connected to the second end face of the slab optical waveguide. Each of the second optical waveguides includes a first cavity connected to the slab optical waveguide and a second cavity acutely connected through a first reflecting surface to the first cavity. The second cavity is terminated by a second reflecting surface. Each second cavity is so configured as to be folded back to the corresponding first cavity, so that the optical device can be made compact in setting a required optical path difference between the second optical waveguides. This optical device can be used as an optical multiplexer or an optical demultiplexer in a system adopting WDM.

Abstract: A substrate (10) has a surface (10A) containing at least one photolithographically defined feature (12, 14A, 14B) for containing a gas or fluid of interest. The substrate further includes at least one region (10B) containing a selected optical gain medium in combination with scattering particles or sites for generating light having a desired wavelength in response to a pump source, such as a laser (20) or a lamp. The at least one region is optically coupled to the at least one photolithographically defined feature for illuminating a portion of the sample with the light having the desired wavelength. The substrate may be comprised of a glass, a polymer, or a semiconductor. In one embodiment at least one optical waveguide (16) is formed in the substrate for conveying light from the pump source to the region containing the gain medium and scatterers.

Abstract: A method of controlling a wavelength of emitted light in a network system having a light transmission line for transmitting light, light-emitting means having a plurality of discrete continuous-wavelength-tunable ranges and emitting the light to the light transmission line, and detecting means for detecting light on the light transmission line, includes detecting, by the detecting means, a wavelength falling within one of the plurality of continuous-wavelength-tunable ranges of the light-emitting means which does not interfere with any wavelengths of light being transmitted on the light transmission line, and emitting, to the light transmission line, light from the light-emitting means at the wavelength detected in said detecting step.

Abstract: A narrow-band laser apparatus comprising a laser generating section having laser activity and capable of generating laser beam; bandwidth narrowing section which is provided on one end side of the laser generating section on the optical axis of the laser beam generated in the laser generating section to narrow the bandwidth of the laser beam by means of at least one angel-dispersion wavelength selection element, fold back the laser beam in the narrowed band and output the folded laser beam toward the laser generating section; beam folding section which is provided on the other end of the laser generating section on the optical axis of the laser beam generated in the laser generating section to fold back the input laser beam and reflect the folded laser beam into the laser generating section; and a laser beam branching unit which is provided between the laser generating section and the bandwidth narrowing section to permit part of the laser beam input from the laser generating section to pass therethrough into

Abstract: A transverse pumping system for a laser rod uses orthogonally arranged banks of laser diodes which create overlapping patterns of illumination inside the rod.

Abstract: A gas discharge excitation laser device having an improved response of an actual output to transition from a laser output ON command to a laser output OFF command. When a command output is switched from ON to OFF at time it2 after passing an ON period Ton, an output command voltage Voc is once suddenly reduced to an OFF-period bottom value Vbott lower than a value VB1 which is suitable for maintaining a base discharge current when laser gas is cold, and then is increased to the value VB1 in a period .tau.. Thus, the actual output is permitted to be instantly interrupted without stopping the discharge. Vbott is a function of .eta.=(Pc/Pmax).times.Beam ON period, and is gradually reduced to a lower-limit clamp value VB2. Vbott(.eta.)=VB1-[(VB1-VB2)/.eta.B2].eta. (where 0.ltoreq..eta..ltoreq..eta.B), Vbott(.eta.)=VB2 (where .eta.>.eta.B). In the equations, Pc is a laser output during the beam ON period, Pmax is a maximum rated laser output, and .eta.B2 is a value of .eta. when Vbott(.eta.) is reduced to VB2.

Abstract: A passive mode-locked linear-resonator fiber laser using polarization-maintaining fibers and a saturable absorber to produce ultra short pulses and a long-term reliable operation with reduced maintenance. Such a fiber laser can be configured to produce tunable pulse repetition rate and tunable laser wavelength.

Abstract: An optical attenuator is provided with a metal-doped optical fiber having a core doped with a transition metal that absorbs light, and a connector that connects this metal-doped optical fiber to an outside transmission line. The core is doped with a transition metal so as to have a uniform rate of attenuation per unit of length. The amount of attenuation may thus be controlled by setting the length of the optical fiber containing this core. The construction adopted for the connector may be fused splicing, mechanical splicing, or optical connection. A transition metal is doped in the core at a uniform concentration. This optical attenuator may also be provided with an exchange section for switching among a plurality of metal-doped optical fibers having mutually differing lengths. Only one type of metal-doped fiber need be produced, and the fiber is used by varying its length.

Abstract: A photonic crystal device and method. The photonic crystal device comprises a substrate with at least one photonic crystal formed thereon by a charged-particle beam deposition method. Each photonic crystal comprises a plurality of spaced elements having a composition different from the substrate, and may further include one or more impurity elements substituted for spaced elements. Embodiments of the present invention may be provided as electromagnetic wave filters, polarizers, resonators, sources, mirrors, beam directors and antennas for use at wavelengths in the range from about 0.2 to 200 microns or longer. Additionally, photonic crystal devices may be provided with one or more electromagnetic waveguides adjacent to a photonic crystal for forming integrated electromagnetic circuits for use at optical, infrared, or millimeter-wave frequencies.

Abstract: A system and method for reducing wavefront distortion in high-gain diode-pumped laser media by providing a non-uniform current profile to be delivered to a pumping array comprised of laser diodes distributed on a laser medium. A signal processor provides for partitioning an electric current emitted from a diode driver such that the pumping array receives a non-uniform current profile resulting in a controlled thermal gradient near the periphery of the laser substrate. By controlling this thermal gradient at the region where an exit laser beam leaves the laser medium, the thermally-induced exit beam distortion is minimized.

Abstract: The light emitted by the laser diode 1 is put into an interference optical filter 5. The light passing through the interference optical filter 5 and the reflected light are respectively received in photo diodes PD1, PD2. Their output ratio is calculated by an adder 13, a subtracter 14, and a divider 15, and a wavelength signal is obtained. The difference of the output ratio and reference value is detected as error signal by an error detector 16, and the emission wavelength of the laser diode 1 is controlled so that the error signal may be zero.