46results about How to "Absorption loss" patented technology

Semiconductor laser diodes, particularly high power AlGaAs-based ridge-waveguide laser diodes, are often used in opto-electronics as so-called pump lasers for fiber amplifiers in optical communication lines. To provide the desired high power output and stability of such a laser diode and avoid degradation during use, the present invention concerns an improved design of such a device, the improvement in particular significantly minimizing or avoiding (front) end section degradation of such a laser diode and significantly increasing long-term stability. This is achieved by separating the waveguide ridge into an active main ridge section (4) and at least one separate section (12) located at an end of the laser diode, which may be passive. The separation is provided by a trench or gap (10) in the waveguide ridge. The active waveguide section (4) is at least partly covered by the electrode (6) providing the carriers that does not extend to cover the separate ridge section (12), which thus remains essentially free of carriers injected through said electrode (6). There may be a plurality such separate ridge sections, e.g. two separate ridge sections (12, 212), one at each end of the laser diode, dividing the ridge waveguide into three ridge sections, an active main ridge section (4) in the center and a passive separate ridge section (12, 212) at either end. The trenches (10, 110) between the sections and / or the shape and size of the separate ridge section (s) (12, 212) may be adjusted to act as spatial mode filters.

A reflective film includes microlayers arranged into optical repeat units to reflect light in an extended wavelength band, with thinner and thicker ones of the optical repeat units being disposed generally towards a thin side and thick side, respectively, of the film. The microlayers are tailored to provide the film with a reflectivity, for p-polarized light incident in a first plane, that decreases by at least half from an initial value at normal incidence to a value R1 at an incidence angle θoblique. The film has a reflectivity for p-polarized light incident in a second plane of R2 at the angle θoblique, where R2>R1. A polarizer is combined with the reflective film, the combination defining an oblique transmission lobe, and the thick and thin sides of the reflective film are oriented relative to the polarizer to reduce an azimuthal width Δφ of the transmission lobe.

An isotopically-altered, silica based optical fiber is provided having lower losses, broader bandwidth, and broader Raman gain spectrum characteristics than conventional silica-based fiber. A heavier, less naturally abundant isotope of silicon or oxygen is substituted for a lighter, more naturally abundant isotope to shift the infrared absorption to a slightly longer wavelength. In one embodiment, oxygen-18 is substituted for the much more naturally abundant oxygen-16 at least in the core region of the fiber. The resulting isotopically-altered fiber has a minimum loss of 0.044 dB / km less than conventional fiber, and a bandwidth that is 17 percent broader for a loss range between 0.044-0.034 dB / km. The fiber may be easily manufactured with conventional fiber manufacturing equipment by way of a plasma chemical vapor deposition technique. When a 50 percent substitution of oxygen -18 for oxygen-16 is made in the core region of the fiber, the Raman gain spectrum is substantially broadened.

The present invention provides an electromagnetic wave resonator that is capable of showing surface wave resonance typically as outstanding plasmon resonance and can be manufactured industrially with excellent reproducibility and efficiency by combining currently available microprocessing technologies. The electromagnetic wave resonator of the present invention includes a first negative dielectric surface, a second negative dielectric surface and a positive dielectric thin film disposed between the first and the second negative dielectric surfaces. The positive dielectric thin film has an end face having an electromagnetic wave introduced therefrom. Intensity of the electromagnetic wave having a predetermined wavelength and being introduced from the end face is enhanced in the electromagnetic wave resonator due to resonance of a surface wave having an electric field component in a direction of film thickness of the positive dielectric thin film and without having a cut-off frequency.

According to the present invention, sufficient light trapping effect can be exhibited and series resistance can be kept small, by sequentially forming a silicon based low refractive index layer and a thin silicon based interface layer on a backside of a photoelectric conversion layer observed from a light incident side, and as a result a silicon based thin film solar cell may be provided efficiently and at low cost.

An electrically pumped lateral emission electroluminescent device may include a slotted waveguide including a top silicon layer having a thickness between 150 nm and 300 nm and a refraction index associated therewith, and a bottom silicon layer having a thickness between 150 nm and 300 nm and a refraction index associated therewith. A core layer may include silicon oxide between the top and bottom layers and a thickness less than 70 nm. A core layer refraction index may be greater than each of the top and bottom layer refraction indices. A core layer portion may be in a direction of light propagation and may be doped with erbium, and may include silicon nanocrystals. A portion of each of the top and bottom layers may coincide with the core layer portion and may be doped so that the top and bottom layer portions are electrically conductive to define top and bottom plates.