In an example, a tandem pumped fiber amplifier may include a seed laser, one or more diode pumps, and a plural core fiber including a first core and a second core, the second core surrounding the first core. The plural core fiber may include a first section to operate as an oscillator and a second different section to operate as a power amplifier. The one or more diode pumps may be optically coupled to the first section of the plural core fiber, and the seed laser may be optically coupled to the first core.

Aspects of the present disclosure describe photonic circuits that include an amplifier section or multiple amplifier sections to boost the output power of an optical transmitter and includes additional components includingbut not limited toa band pass optical filter, a wavelength demultiplexer and additional componentsall on a single chip.

Aspects of an optical communications network are described that include two or more optical fibers arranged to allow communication in the same or in opposite directions. The optical network includes a first optical amplifier coupled to the first optical fiber, a second optical amplifier coupled to the second optical fiber, and an optical coupler that allows excess optical power from the first optical fiber to be provided for amplification of signals traversing the second optical fiber. The disclosed systems and devices thus enable excess power from one channel to be utilized to enable amplification of signals traveling on a different channel.

The invention is optical configurations for constructing laser oscillators or laser amplifiers that comprise an extremely short fiber (typically tens of cm long or below, e.g. 5 cm to 30 cm). In order to overcome the absorption limitation due to the very short length of the fiber, the present invention employs a multi pump-pass scheme for pump light confinement. This scheme is based on the small angular overlap between the lasing and pump beams. The multi pump-pass method of the invention leads to efficient fiber laser oscillators and amplifiers having pulse duration of a few ns, with high average and peak power output that is comparable to the state-of-the-art solid state lasers.

A fiber laser source is configured to an external reflective element disposed along the signal path of the fiber laser. The external reflective element comprises a wavelength-selective device that is designed to reflect all of the pump light that reaches the reflective element, while allowing the generated laser emission to pass through. The reflected pump light is then directed to pass through the fiber laser a second time to generating an additional amount of laser emission output. The external reflective element preferably comprises a fiber Bragg grating with a Bragg wavelength ?.sub.G that matches the pump wavelength ?.sub.P to provide essentially 100% reflection of any unabsorbed pump light.

The system and method of integrated seed and high power pump source generates two wavelengths outside the effective gain bandwidth of a single gain medium without using two unique pump sources in a fiber amplifier train. The system and method uses a single pump power oscillator that passes a seed wavelength with no loss and minimal amplification to pump integrated amplifiers in both directions (forward and backward) resulting in amplification of the seed wavelength.

In an example, a tandem pumped fiber amplifier may include a seed laser, one or more diode pumps, and a plural core fiber including a first core and a second core, the second core surrounding the first core. The plural core fiber may include a first section to operate as an oscillator and a second different section to operate as a power amplifier. The one or more diode pumps may be optically coupled to the first section of the plural core fiber, and the seed laser may be optically coupled to the first core.

An array of optical amplifiers that recycles the unused pump power of some or all constituent amplifiers thereof, thereby beneficially improving pump-power utilization therein compared to that of conventional optical amplifiers. In an example embodiment, different amplifiers of the array can be configured to receive approximately equal pump power and be used to independently amplify different respective optical signals. In various embodiments, the unused pump power can be recycled using one or more optical couplers and/or optical paths that appropriately interconnect different amplifiers of the array. Some embodiments have one or more optical loops configured to operate as a ring laser that regenerates pump light in response to the unused pump power being coupled thereto. Some embodiments provide a spectral gain profile suitable for amplifying WDM signals in at least some of the constituent amplifiers of the array.

An array of optical amplifiers that recycles the unused pump power of some or all constituent amplifiers thereof, thereby beneficially improving pump-power utilization therein compared to that of conventional optical amplifiers. In an example embodiment, different amplifiers of the array can be configured to receive approximately equal pump power and be used to independently amplify different respective optical signals. In various embodiments, the unused pump power can be recycled using one or more optical couplers and/or optical paths that appropriately interconnect different amplifiers of the array. Some embodiments have one or more optical loops configured to operate as a ring laser that regenerates pump light in response to the unused pump power being coupled thereto. Some embodiments provide a spectral gain profile suitable for amplifying WDM signals in at least some of the constituent amplifiers of the array.

Embodiments of the present disclosure provide an optical repeater and an optical fiber communications system. An implementation solution of the optical repeater includes: a first input end of the optical repeater, a first output end of the optical repeater, a first erbium doped fiber, a first coupler, a second coupler, and a first pump light processing component, where the first input end of the optical repeater is connected to an input end of the first erbium doped fiber, an output end of the first erbium doped fiber is connected to an input end of the first coupler, a first output end of the first coupler is connected to a first input end of the second coupler, and an output end of the second coupler is connected to the first output end of the optical repeater.