Abstract: An apparatus for generating at least three visible light beams of different output wavelengths for display purposes includes a passively mode-locked solid-state thin-disk laser and a device, including an optical parametric oscillator (OPO) for at least partially converting the primary light beam into electromagnetic radiation having the at least three different output wavelengths. The OPO is preferably an optical fiber feedback OPO. An optical fiber feedback OPO includes a nonlinear optical element and feedback device for feeding back at least a portion of the radiation emitted by the nonlinear medium to the nonlinear element. The feedback device includes an optical fiber.

Abstract: An optical waveguide with at least a guiding lamina (10) of optical material bonded by direct interfacial bonding to a superstructure lamina (20) of optical material, in which regions of the guiding lamina have modified optical properties so as to define a light guiding path along the guiding lamina. In a particular example, a periodically poled LiNbO3 planar waveguide is buried in LiTaO3 by direct interfacial bonding and precision polishing techniques and used in an optical frequency doubling system.

Abstract: The apparatus for generating at least three visible light beams of different output wavelengths for display purposes comprises a passively mode-locked solid-state thin-disk laser and means for at least partially converting said primary light beam into electromagnetic radiation characterized by said at least three different output wavelengths including an optical parametric oscillator (OPO). The OPO is preferably an optical fiber feedback OPO. An optical fiber feedback OPO comprises a nonlinear optical element and feedback means for feeding back at least a proportion of the radiation emitted by the nonlinear medium to the nonlinear element, wherein the feedback means comprise an optical fiber.

Abstract: An optical fibre amplifier comprises a thulium-doped optical fibre pumped at 790 nm by a semi-conductor diode laser coupled to the fibre via optical fibre coupler. The amplifier is optically coupled in series to a pair of systems fibres to provide amplification to optical signals.

Abstract: An optical fiber laser includes an optical fiber having a core (14), an inner cladding (12) surrounding the core and an outer cladding (16) surrounding the inner cladding and core. The core (12) is doped with a first laser-active material, preferably, thulium. The inner cladding is doped with a second different laser-active material, for example, neodymium and is pumped by a multimode pump light source such as a diode array. Pumping of the inner cladding (12) causes laser emission in the inner cladding material which, in turn, serves as pump radiation for the laser-active dopant in the core (14).

Abstract: A ring laser (10) incorporates a laser rod (R) with end faces (R.sub.1, R.sub.2). The first face (R.sub.1) is coated for high reflectivity at the laser wavelength and the second (R.sub.2) for high transmission at this wavelength. The first face (R.sub.1) provides one cavity end mirror, and a concave mirror (M.sub.1) spaced apart from the rod (R) provides the other. A rhombic prism (P) between the rod (R) and mirror (M.sub.1) defines differing (figure of eight) forward and return paths (14 to 17, 18 to 21) for cavity radiation passing from one end mirror (R.sub.1 or M.sub.1) to the other and returning. The prism (P) presents Brewster's angle refracting surfaces. The second rod face (R.sub.2) is tilted to produce an optical path in two planes. A magnetic field (B) along the rod axis (R.sub.a) produces Faraday rotation of polarization. This counteracts rotation arising from non-coplanar optics for one direction of propagation around the laser cavity (10) but not the other.