Abstract: An optical isolator for use with high power, collimated laser radiation includes an input polarizing optical element, at least one Faraday optical element, at least two reflective optical elements for reflecting laser radiation to provide an even number of passes through said at least one Faraday optical element, at least one reciprocal polarization altering optical element, an output polarizing optical element, at least one light redirecting element for remotely dissipating isolated or lost laser radiation. The isolator also includes at least one magnetic structure capable of generating a uniform magnetic field within the Faraday optical element which is aligned to the path of the collimated laser radiation and a mechanical structure for holding said optical elements to provide thermal gradients that are aligned to the path of the collimated laser radiation and that provide thermal and mechanical isolation between the magnetic structure and the optical elements.

Abstract: A high power Faraday isolator or rotator includes, at least one Faraday optical element, and a magnetic structure capable of generating a magnetic field within the at least one Faraday optical element. The at least one Faraday optical element comprises a Potassium Terbium Fluoride (KTF) crystal grown or manufactured along the [113] crystal orientation and which is oriented such that the light propagating through the Faraday isolator is within 2 degrees of the [113] crystal orientation.

Abstract: A kW Class optical isolator employs negative feedback to yield low focal shift over dynamically changing power levels. The isolator is useful as a kW fiber laser output isolator.

Abstract: Transparent heat-conductive layers of significant thickness are bonded or adhered to opposing optical faces of a Faraday optic to form a Faraday optic structure that can be used with beam-folding mirrors and an external magnetic field to form a multi-pass Faraday rotator with minimal thermal gradient across the beam within the Faraday optic. The transparent heat conductive layers conduct heat through the Faraday optic substantially parallel to the beam propagation axis for each pass through the Faraday optic structure and thereby reduce thermal gradients across the beam cross section that would otherwise contribute to thermal lens focal shifts and thermal birefringence in the Faraday optic structure. The multi-pass Faraday rotator of this invention is suitable for use with any device based upon the Faraday effect such as optical isolators, optical circulators and Faraday mirrors that are scalable with beam size to power levels in excess of 2 kW.

Abstract: A kW Class optical isolator employs negative feedback to yield low focal shift over dynamically changing power levels. The isolator is useful as a kW fiber laser output isolator.

Abstract: A Faraday rotator is formed of a class of semiconductor materials of low free carrier density wherein, in the presence of a suitable magnetic field, interband transition Faraday rotation is opposite in sign from free carrier effect Faraday rotation and interband transition Faraday rotation predominates over free carrier effect Faraday rotation such that net Faraday rotation can remain nearly unchanged over broad IR spectral regions where the short wavelength limit is typically near the bandgap absorption. Thus, the class of semiconductors meeting these conditions can function as high performance broadband optical isolators in the infrared. Suitable materials include InAs of suitable purity.

Abstract: An axially symmetric permanent magnet structure with tunable longitudinal fields is described wherein selected radial magnet sectors in a truncated Halbach array configuration are tiltable. The tunable magnet structure is particularly useful in Faraday devices, such as Faraday rotators, Faraday mirrors, optical circulators and optical isolators.

Abstract: Faraday rotator or isolator with mode stripping ferrules and collimators having fiber pigtailed mode stripping components. An example is a compact Faraday Isolator module employing mode stripping ferrules and mode stripping collimators at the input and/or at the output of a fiber pigtailed Faraday Isolator. Two basic isolator types are a Polarization Independent Faraday isolator and a Polarization Maintaining Faraday isolator. The device is substantially immune to damage due to back-reflection, thermal lensing, energy leakage and absorption. Mode stripped optical energy propagating in the reverse direction is diverted onto a heat absorbing and heat sinking structure, as for example at the input of a compact birefringent wedge-based PI isolator. Alternatively, the optical energy propagating in the reverse direction is angularly refracted away from the forward incident beam path and is coupled into the energy dispersive cladding of the input fiber or the ferrule itself.

Abstract: Faraday rotator or isolator with mode stripping ferrules and collimators having fiber pigtailed mode stripping components. An example is a compact Faraday Isolator module employing mode stripping ferrules and mode stripping collimators at the input and/or at the output of a fiber pigtailed Faraday Isolator. Two basic isolator types are a Polarization Independent Faraday isolator and a Polarization Maintaining Faraday isolator. The device is substantially immune to damage due to back-reflection, thermal lensing, energy leakage and absorption. Mode stripped optical energy propagating in the reverse direction is diverted onto a heat absorbing and heat sinking structure, as for example at the input of a compact birefringent wedge-based PI isolator. Alternatively, the optical energy propagating in the reverse direction is angularly refracted away from the forward incident beam path and is coupled into the energy dispersive cladding of the input fiber or the ferrule itself.

Abstract: A monolithic ferrule/endcap/optical fiber structure is provided wherein an optical fiber is terminated in a ferrule and bonded by fusion to form a monolithic unit which minimizes optical loss and is typically capable of transmitting high power laser radiation, preferably on the order of 500 W and higher, without damage to the optical fiber and ferrule. Ferrule, endcap, optical fiber and fusible powder are composed of material of substantially the same physical characteristics such that, when all are fused together, the structure so formed is monolithic and the optical path is transparent.

Abstract: A monolithic ferrule/endcap/optical fiber structure is provided wherein an optical fiber is terminated in a ferrule and bonded by fusion to form a monolithic unit which minimizes optical loss and is typically capable of transmitting high power laser radiation, preferably on the order of 500 W and higher, without damage to the optical fiber and ferrule. Ferrule, endcap, optical fiber and fusible powder are composed of material of substantially the same physical characteristics such that, when all are fused together, the structure so formed is monolithic and the optical path is transparent.

Abstract: A planar unidirectional solid state laser is realized in non-birefringent (isotropic or cubic) material by inducing a reciprocal polarization rotation along a lasing path within the material through a mechanical stress or by modifying the material to change the index of refraction along the lasing path. Together with means for providing nonreciprocal polarization rotation, such as with the Faraday Effect, the invention enables construction of unidirectional lasers, and more specifically thick film, single-frequency CW or Q-switched tunable ring lasers, with the advantage of both flat and ring structures. A variable-output coupled solid state ring laser employing an evanescent wave output coupling in the form of a prism is also described.