Abstract:
The present invention relates to an optical coupling between an end of an optical fibre and an end of a lens, which provides a reliable joint with a determined spacing and angular orientation. The optical coupling permits movement of the end of the optical fibre relative to the lens in at least two alignment directions. Advantageously, the present invention permits movement of the end of the optical fibre relative to the end of the lens in a direction perpendicular to the optical axis of the lens, before the optical coupling is secured. The optical fibre within an optical fibre tube/ferrule and the lens are secured within separate sleeves and the sleeves bonded together. The end of the optical fibre and the end of the lens are optically aligned before being secured in place relative to each other. Alternatively, the invention provides similar advantages in coupling two lenses to one another via separate sleeves they are contained within.
Abstract:
A multi-stage optical isolating device having at least three stages includes birefringent crystals for separating shifting and combining an incoming beam of light into orthogonal polarized beams. The multi-stage device also includes at least three Faraday rotators that rotate incoming light propagating through the device in a same direction. The inclusion of a reciprocal rotator in the form of a half-wave plate advantageously obviates orienting the Faraday rotators differently.
Abstract:
The present invention relates to a coupling element for coupling between optical elements, for instance a ferrule encased fiber end and a lens, two lenses, or filter and lens assemblies, which provides a reliable joint with a determined spacing and angular orientation between them if needed. Advantageously, the coupling in accordance with the present invention does not obscure optical transmission through the coupling with an epoxy layer. A stand off element is provided which has opposite reference surfaces for joining the end faces of the optical elements and a central aperture, slot or equivalent open area for light transmission. In use the open area is aligned, for example with the fiber end and the desired port in the lens. Adhesive connection can be provided between the opposite surfaces of the stand off element and the coupling end faces of the optical elements. No epoxy is applied over the open area. Other securing methods such as external securing elements can be used. Alignment is established by the planar surfaces of the stand off element. The separation between elements can be accurately established by selecting the desired thickness between faces of the stand off element. Alternatively, the surfaces of the stand off element may be angled to compliment the surfaces of the elements, or to provide an accurate angled coupling. Loss is reduced by not transmitting light through an epoxy layer.
Abstract:
A polarization beam splitter combiner uses a birefringent crystal that is a fraction of the size of conventional crystals used in similar devices. Since the crystal is considerably shorter in length, the beam passing through the crystal can be uncollimated, spreading very little from one end to the other. Launching uncollimated beams through a short small crystal obviates the requirement for lenses at the end face of the crystal having two waveguides coupled thereto. Since lenses are not required the waveguides at the input/output end face can be very closely spaced apart. Conventional lensed devices utilizing a pair of lenses at an input/output end face must be considerably larger in order to accommodate the lenses and resulting collimated beams.
Abstract:
An at least 3-port optical circulator has first group of optical components, and a second group of optical components, the first group being separated from the second group by an optical distance "1". Each group of optical components has a divider and combiner for dividing an input beam into two beams having orthogonal polarizations and for combining two beams having orthogonal polarizations into a single beam. Furthermore, each group has a GRIN lens for at least substantially collimating or focussing input light, and a polarization rotator between the first divider and combiner and the GRIN lens for making two orthogonal polarization vectors parallel or the two parallel polarization vectors orthogonal to one of or both of the first and second group of optical elements having beam shifting means disposed to shift two beams having a predetermined same polarization. The beam shifting means are of a thickness and orientation so that a beam of light that propagates from a first port sequentially to a second port and from the second port sequentially to a third port are shifted a distance equal to the distance between the optical axes of the first and the third ports.
Abstract:
This invention relates to a reflective optical isolating device having at least two stages. In one embodiment a polarization independent optical isolating device has an input/output end and a reflector at another end. An isolator is disposed between the reflector and the input/output end. The isolator includes a non-reciprocal rotator in the form of a Faraday rotator, and in one embodiment the isolator also includes two reciprocal rotators. A first end of the isolator includes a birefringent crystal for separating an input beam of light in an input direction and for combing two beams of light in an output direction. The isolator also includes a second birefringent crystal at the other end for combining a separated beam of light on route to the reflector and for separating a combined beam of light in the output direction. In one embodiment two separate single isolation stages are provided, and in another embodiment two stage isolation is provided without providing two single stages of isolation.
Abstract:
A lighting apparatus and method is disclosed for illuminating a surface using solid-state light emitting diodes (LEDs). The lighting apparatus consists of a plurality of LEDs arranged in an array form, a base for mounting the LEDs, an electrical power supply, and a fixing means for attaching said lighting apparatus to a surface to provide an upward lighting. In some embodiments disclosed in the invention, the base has a shaped surface. In other embodiments, a lensing means is provided. In some embodiments, the LEDs are mounted at an angle. According to the present invention, a method for providing an upward lighting to a surface using LEDs is provided, wherein the lighting apparatus is attached near the bottom of the surface to be illuminated and the angle between the plane of said surface and the center of the light beam from the LEDs is less than 45 degrees.
Abstract:
The present invention relates to bi-directional circulators based on interleaver technology, e.g. birefringent crystal interleaver technology, that enables signals containing even number ITU channels to travel in one direction through the device, while signals containing odd number ITU channels travel in the opposite direction. Open and closed three and four port devices are disclosed, as well as several useful implementations of the three port device in combination with other optical components, which result in hybrid uni-directional and bi-directional devices.
Abstract:
An optical coupling arrangement for use in an optical filter is disclosed wherein optical fibre are disposed only along one line in one orientation across an end face of an optical fibre tube having a slanted end face. By disposing slanted/polished optical fibre end faces along a line that is orthogonal to a longitudinal axis of the optical fibre tube, optimum coupling of light is achieved.
Abstract:
A useful device is provided for coupling or splitting optical signals from one port to another. The symmetry of a lens is utilized in a manner whereby two linear arrays of optical ports are disposed adjacent the optical axis of the lens equidistant from the optical axis of the lens. An at least partially reflecting optical element is disposed at a collimating end of the lens. Signals launched into one array of ports reflects back to the second array of ports at the same end. In another embodiment of the invention utilizing these two linear arrays of waveguides, two matched lenses having an element disposed between are used as a coupler/splitter. In this arrangement ports are positioned on opposite sides of the optical axis equidistant from it.