Abstract: An optical arrangement and method of filtering include a beam splitter that accepts an incident beam and transmits light from the incident beam of a first polarization and reflects light from the incident beam of a second polarization. The transmitted light is a first beam and the reflected light is a second beam. A first spectral filter, receives the first beam, reflects a first spectral band of the first beam, and transmits the remainder of the first beam. A second spectral filter receives the remainder of the first beam and reflects a second spectral band of the first beam. The first and second spectral filters can also receive the second beam and reflect similar first and second spectral bands. The spectral bands are then returned to the beam splitter, where they may be directed toward a dispersal element or an array of photodetectors.

Abstract: A diffractive outcoupler, for use in a cavity of a laser, includes a surface phase grating for receiving radiation from a laser source and has rectangular grooves with a depth D, a first reflector located to receive a first diffracted portion of the radiation from the grating and to reflect the first diffracted portion back toward the grating, and a second reflector located to receive a second diffracted portion of the radiation from the grating and to reflect the second diffracted portion back toward the grating. The depth D of the grooves satisfies a relationship with the refractive index of the grating to permit transmission of the second harmonic of the radiation through the grating while causing portions of the first harmonic passing through the grooves and elevations of the grating to destructively interfere.

Abstract: An optical fiber delay line includes: multiple differential delay lines; and multiple switchers connecting the differential delay lines in pairs. Using, for example, N+1 differential delay lines numbered by k from 0 to N, the k-th differential delay line delays an input optical signal by an amount of time (tkA?tkB)=2k ?, so that the electronically controlled switchers allow digitally controlling the delay over a range from 0 to (2N+1?1)? with a time resolution of ?. The delay line can also be used simultaneously as a phase modulator, enabling a system of synchronization that can be realized entirely electronically and may be very useful in the case of large fiber arrays comprising a number of fiber modules such as beam splitters, fiber amplifiers, connectors, and collimators. The delay line can also be used as a commutator, for controlled switching of optical signals between channels.

Abstract: A system and/or method for temporal profiling of an incident laser pulse. The system and/or method includes a laser beam source for providing the incident laser pulse and a Bragg grating (BG) coupled to receive the incident laser pulse. The BG includes a distribution of diffraction efficiency density at various depths within the BG and provides a plurality of diffracted beamlets from the incident laser pulse. The system and/or method combines the diffracted beamlets into a single temporally shaped laser beam.

Abstract: An apparatus for directing light beams onto a target comprising a beam splitter for splitting a main beam into a first split beam and a second split beam; a first beam path for the first split beam, the first beam path including a first aperture, a first lens and a second lens; a second beam path for the second split beam, the second beam path including a second aperture, a third lens and a fourth lens; a plurality of mirrors arranged such that the first split beam and the second split beam intersect at the target. An apparatus can also include means for placing a target in the image plane of a first aperture and a second aperture.

Abstract: A system and/or method for spatial beam shaping of an incident laser beam. The system and/or method includes a laser beam source for providing the incident laser beam and a Bragg grating (BG) coupled to receive the incident laser beam from the laser beam source. The BG has a thickness that is not less than a cross sectional size of the incident laser beam in the plane of beam diffraction. The BG produces a diffracted beam from the incident laser beam and the various depths within the BG include a distribution of diffraction efficiency density for spatially shaping the incident laser beam into the diffracted beam.

Abstract: A nonreciprocal optical element and method for operating it to effect separate control of intensity and phase (or optical path length) of counter propagating beams over a very wide range. The nonreciprocal optical element includes a circulator for routing a first signal from a first port to a second port and a second signal from the second port to a third port, a third signal from the third port to a fourth port and a fourth signal from the fourth port to the first port; a first mirror for reflecting a signal output by the second port back into the second port; and second mirror for reflecting a signal output by the fourth port back into the fourth port. Polarization rotation elements such as quarter-wave plates are disposed between the mirrors and the second and fourth ports to preserve the polarization of the input beams. Filters are disposed between these ports and mirrors to adjust the transmittance of the input and output signals.

Abstract: A method for manufacturing a distributed feedback reflector comprises forming a waveguide (32) on a wafer, applying a photoresistive material to the wafer, forming a grating on the photoresistive material, developing the photoresistive material, and milling the substrate to form the distributed feedback reflector.

Abstract: Novel volume holographic elements were made from Bragg diffractive gratings in photo-thermo-refractive (PTR) glass with absolute diffraction efficiency ranging from greater than approximately 50% up to greater than approximately 93% and total losses below 5%. Both transmitting and reflecting volume diffractive elements were done from PTR glasses because of high spatial resolution enabling recording spatial frequencies up to 10000 mm−1. The use of such diffractive elements as angular selector, spatial filter, attenuator, switcher, modulator, beam splitter, beam sampler, beam deflectors controlled by positioning of grating matrix, by a small-angle master deflector or by spectral scanning, selector of particular wavelengths (notch filter, add/drop element, spectral shape former (gain equalizer), spectral sensor (wavelength meter/wavelocker), angular sensor (pointing locker), Bragg spectrometer (spectral analyzer), transversal and longitudinal mode selector in laser resonator were described.

Abstract: A novel process is proposed for the volume diffractive element (Bragg grating) fabrication in photosensitive silicate glasses doped with silver, cerium, fluorine, and bromine. The process employs a photo-thermo-refractive (PTR) glass of high purity exposed to ultraviolet (UV) radiation of a He—Cd laser at 325 nm followed by thermal development at temperatures from 480° C. to 580° C., preferably at 520° C., from several minutes to several hours. Absolute diffraction efficiency up to 95% was observed for 1 mm thick gratings. Maximum spatial frequency recorded in PTR glass was about of 10,000 mm−1. No decreasing of diffraction efficiency were detected at low spatial frequencies. Original glasses were transparent (absorption coefficient less than 1 cm−1) from 350 to 4100 nm. Induced losses in exposed and developed glass decreased from 0.3 to 0.03 cm−1 between 400 and 700 nm, respectively, and did not exceed 0.01-0.02 cm−1 in the infrared (IR) region from 700 to 2500 nm.

Abstract: Novel volume holographic elements were made from Bragg diffractive gratings in photo-thermo-refractive (PTR) glass with absolute diffraction efficiency ranging from greater than approximately 50% up to greater than approximately 93% and total losses below 5%. Both transmitting and reflecting volume diffractive elements were done from PTR glasses because of high spatial resolution enabling recording spatial frequencies up to 10000 mm−1. The use of such diffractive elements as angular selector, spatial filter, attenuator, switcher, modulator, beam splitter, beam sampler, beam deflectors controlled by positioning of grating matrix, by a small-angle master deflector or by spectral scanning, selector of particular wavelengths (notch filter, add/drop element, spectral shape former (gain equalizer), spectral sensor (wavelength meter/wavelocker), angular sensor (pointing locker), Bragg spectrometer (spectral analyzer), transversal and longitudinal mode selector in laser resonator were described.

Abstract: An apparatus and method for physically separating non-metallic substrates forms a microcrack in the substrate and controllingly propagates the microcrack. An initial mechanical or pulsed laser scribing device forms a microcrack in the substrate. If a pulsed laser is used, it forms a crack inside the substrate that does not extend to either the upper or lower surface. A scribe beam is applied onto the substrate on a separation line. A coolant stream intersects with, or is adjacent to, the trailing edge of the scribe beam. The temperature differential between the heat affected zone of the substrate and the coolant stream propagates the microcrack. Two breaking beams on opposing sides of the separation line follow the coolant stream. The breaking beams create controlled tensile forces that extend the crack to the bottom surface of the substrate for full separation. The scribe and break beams and coolant stream are simultaneously moved relative to the substrate.