Abstract: Disclosed are fiber amplifiers with multiple pumping sources including multiple optical sources or an optical comb source with multiple spectral lines. A comb source may include generating a plurality of evenly spaced or nearly evenly spaced spectral lines. The optical comb source may pump a fiber by propagating optical energy at the multiple spectral lines through the fiber. The comb source may cause gain in the fiber at in a band of wavelengths different from the spectral lines of the comb source. A weak signal injected into the fiber that propagates in the fiber will experience optical gain in the fiber producing an amplified signal at the wavelength within a band of wavelengths different from the comb source wavelengths. When the bandwidth of the multiple bands of gain is wide, the amplifier may be referred to as an ultra-wideband amplifier.

Abstract: A system comprises a trunk submarine cable, an offshore optical and power switching unit connected to the trunk submarine cable, and a plurality of feeder submarine cables connected to the offshore switching unit. The offshore switching unit is configured to dynamically connect data communication channels of a selected feeder submarine cable among the plurality of feeder submarine cables with data communication channels of the trunk submarine cable.

Abstract: A system comprises a trunk submarine cable, an offshore optical and power switching unit connected to the trunk submarine cable, and a plurality of feeder submarine cables connected to the offshore switching unit. The offshore switching unit is configured to dynamically connect data communication channels of a selected feeder submarine cable among the plurality of feeder submarine cables with data communication channels of the trunk submarine cable.

Abstract: A system comprises a trunk submarine cable, an offshore optical and power switching unit connected to the trunk submarine cable, and a plurality of feeder submarine cables connected to the offshore switching unit. The offshore switching unit is configured to dynamically connect data communication channels of a selected feeder submarine cable among the plurality of feeder submarine cables with data communication channels of the trunk submarine cable and to reconfigure power in the case of power faults.

Abstract: Submarine optical fiber communications are described. A submarine optical fiber communications system can be configured to transmit optical signals within a first band of the electromagnetic spectrum in a first direction, and to transmit optical signals within a second band of the electromagnetic spectrum in a second direction. The bands can be C band, L band, or both bands.

Abstract: A fiber optic switching network includes a comb laser source that provides laser light at a plurality of wavelengths on a single optical fiber. Light from the comb laser source is directed into different optical fibers by a demultiplexer such as an arrayed waveguide grating (AWG) or cyclic AWG. Light from the demultiplexer is modulated with one or more demodulators and re-combined with a multiplexer into a single optical fiber for transmission to a destination.

Abstract: Submarine optical fiber communications are described. A submarine optical fiber communications system can be configured to transmit optical signals within a first band of the electromagnetic spectrum in a first direction, and to transmit optical signals within a second band of the electromagnetic spectrum in a second direction. The bands can be C band, L band, or both bands.

Abstract: A fiber optic switching network includes a comb laser source that provides laser light at a plurality of wavelengths on a single optical fiber. Light from the comb laser source is directed into different optical fibers by a demultiplexer such as an arrayed waveguide grating (AWG) or cyclic AWG. Light from the demultiplexer is modulated with one or more demodulators and re-combined with a multiplexer into a single optical fiber for transmission to a destination.

Abstract: An upgrade method in which Raman amplification is added to an existing transmission system to provide an increase in power budget and permit a substantial increase in transmission capacity either by time division multiplexing (TDM), wavelength division multiplexing (WDM), or a combination thereof. The power budget improvement permits higher transmission capacity by increasing either a single channel data rate and/or the number of wavelength division multiplexed data channels that can be accommodated by existing fiber links.

Abstract: An optical fiber amplifier is pumped by a pair of pump lasers which have at least partially overlapping resonators. In one embodiment, the fiber gain section of the amplifier is located external to the resonators. In another embodiment, the coupler, which couples the pump lasers to the gain section, is located at least partially within said resonators. In a preferred embodiment the resonators are provided with polarization selection properties, and the outputs of the pump lasers are coherent.

Abstract: An optical fiber amplifier is pumped by a fiber pump laser which has a pair of separate active media within a common resonator. The fiber gain section of the amplifier is also located within the resonator.

Abstract: Applicants have discovered that the intermodal beat noise of a fiber multimode laser can be substantially reduced by providing the fiber with an output coupler of broadened bandwidth. In a preferred embodiment, a reduced-noise, high power light source comprises a cladding pumped fiber laser having a chirped output grating. Experiments show that increasing the output bandwidth from 0.254 to 0.577 nm reduces the relative intensity-to-noise ratio 10 dB in a Nd-doped fiber laser. Increasing the bandwidth from 0.2 nm to 0.3 nm in a Yb-doped laser similarly reduces the noise by 12 dB.

Abstract: A low noise optical fiber Raman amplifier (FRA) comprises an upstream and a downstream length of silica-based amplifier fiber, of combined length >200 m, typically >1 km, with an optical isolator disposed between the upstream and downstream lengths of amplifier fiber such that passage of backscattered signal radiation from the latter to the former is substantially blocked. In preferred embodiments counter-propagating pump radiation is coupled into the downstream length of amplifier fiber, and wavelength-selective means are provided for shunting the pump radiation around the optical isolator. The described FRA is advantageously incorporated into optical fiber communication systems. Exemplarily it can serve as power amplifier, as pre-amplifier, or as in-line amplifier. For instance, it can be used to replace conventional opto-electronic repeaters in existing 1.3 .mu.m fiber communication systems, or it can be used as power amplifier in a multi-subscriber optical fiber CATV system.

Abstract: In an optical fiber light source a section of multimode fiber is interposed between an energizing laser (e.g,, a diode laser) and a single mode fiber active medium. In a preferred embodiment the single mode fiber active medium is surrounded by a multimode cladding coupled to the multimode fiber. The source may serve as a pump laser for a fiber amplifier or as an amplified spontaneous emission source. Arrangements for coupling several energizing lasers to the active medium are also described.