Abstract: An optical fiber arrangement has at least two optical fiber sections, each optical fiber section defining an outside longitudinally extending surface. The outside longitudinally extending surfaces are in optical contact with each other. The invention further provides for an amplifying optical device have an optical fiber arrangement as just described, and a pump source. The amplifying optical device is configured such that the pump source illuminates the amplifying optical fiber. A amplifying arrangement is also disclosed. The amplifying arrangement includes a plurality of amplifying optical devices as just described, and each amplifier also has at least one input fiber and a first multiplexer connected to the input fiber. Each amplifier is configured such that at least one of the amplifying optical fibers is connected to the first multiplexer. The amplifying arrangement also has a second multiplexer connected to each of the first multiplexers.

Abstract: An optical fibre arrangement has at least two optical fibre sections, each optical fibre section defining an outside longitudinally extending surface. The outside longitudinally extending surfaces are in optical contact with each other. The invention further provides for an amplifying optical device have an optical fibre arrangement as just described, and a pump source. The amplifying optical device is configured such that the pump source illuminates the amplifying optical fibre. A amplifying arrangement is also disclosed. The amplifying arrangement includes a plurality of amplifying optical devices as just described, and each amplifier also has at least one input fibre and a first multiplexer connected to the input fibre. Each amplifier is configured such that at least one of the amplifying optical fibres is connected to the first multiplexer. The amplifying arrangement also has a second multiplexer connected to each of the first multiplexers.

Abstract: A Raman cascade laser comprising a 1060 nm pump source, an input waveguide and a ring waveguide coupled to the input waveguide. The ring waveguide is at least in part formed of phosphosilicate fiber so as to Raman scatter the pump beam from the pump wavelength to a gain wavelength that is offset from the pump wavelength by a first Raman step of 1330 cm−1. Light is coupled out with an output waveguide coupled to the ring waveguide at an emission wavelength offset by a second Raman step of 1330 cm−1 from the gain wavelength. Other embodiments provide incoherent sources based on the same 2-step Raman cascade, or a 2-step Raman cascade based on a first phosphosilicate 1330 cm−1 Raman step followed by a second step of 680-820 cm−1. With the invention, it is possible to avoid a Raman cascade involving a larger number of steps while at the same time avoiding use of 1300 nm pump sources.

Abstract: An optical coupler for coupling a signal light beam from a signal port (100) and a pump light beam from a pump port (110) into a common port (120) for coupling the pump and signal beams into a double-clad (DC) optical fiber (122) comprising a core (123), an inner clad (124) and an outer clad (125). The DC optical fiber has a section of coreless fiber (128) joined to it to form an extension piece. A free-space optical arrangement (130) combines the pump and signal light beams onto the common port so that the signal light beam is focused onto the core aperture at the buried interface (121) between the DC optical fiber and the coreless extension piece. The high power density signal beam focus is thus moved away from a more sensitive air:glass interface into a buried interface which has a higher damage threshold. In this way, higher signal beam powers can be handled. The invention allows higher power DC pumped amplifiers and lasers to be fabricated.

Abstract: A method of an apparatus for compensating optical non-linearity in optical devices and transmission systems. Two second order interactions are cascaded in phase-mismatched second harmonic generation to accumulate a non-linear phase shift of a fundamental wave. The non-linear phase shift can be set to provide a desired amount of non-linearity compensation. Compensation takes place in a compensating medium having a negative effective non-linear refractive index at the design operating conditions of the compensating medium. Compensators incorporating these principles may be incorporated as passive or active components in optical transmitters, repeaters or receivers. Active components may be tuned by varying the operating condition of the compensating medium, for example by controlling temperature or applied stress.