A photonic lantern couples light from several fibers or fiber cores into one or more fibers or fiber cores. Photonic lanterns are often used to combine several lower-power beams into a single higher-power beam. They can also be used to couple light from multi-core fibers into single-mode, multi-mode, or other multi-core fibers. By modulating the phases of the input beams, the light can be switched from output to outputfor example, between output cores of a multi-core output fiber. If desired, the beams can also be amplified using an active fiber in or coupled to the photonic lantern. A first photonic lantern couples signal light and pump light into the core and cladding, respectively, of an active multi-mode or multi-core fiber. And the active multi-mode or multi-core fiber couples amplified signal light into output fiber(s) via a second photonic lantern.

The present disclosure generally relates optical amplifier modules. In one form for example, an optical amplifier module includes a booster optical amplifier configured to increase optical power of a first optical signal. The module also includes a preamp optical amplifier configured to increase optical power of a second optical signal and a pump laser optically coupled to the booster optical amplifier and the preamp optical amplifier. The pump laser is configured to provide a booster power to the booster optical amplifier and a preamp power to the preamp optical amplifier, the preamp power is effective to induce a gain in optical power to provide a target optical power of the second optical signal from the preamp optical amplifier, and the booster power is dependent on the preamp power.

An optical signal transmitter includes a laser source configured to generate light with different wavelengths, respectively; a wavelength division (WD) demultiplexer configured to redirect the light in different directions based on the different wavelengths, respectively; and a lens array including an array of lenses configured to collimate the light from the WD demultiplexer for transmission in different directions, respectively. The optical signal transmitter may be implemented in a light detection and ranging (LIDAR) apparatus. The optical signal transmitter may further include a 1xN splitter and a set of WD demultiplexers to increase the number of distinct optical signal transmissions.

A forward Raman amplifier includes a plurality of pumping light sources with different wavelengths and the forward Raman amplifier, according to a fiber type or a zero-dispersion wavelength of the fiber, changes the number of pumping light sources to be emitted, changes a power ratio between the plurality of pumping light sources with the different wavelengths or changes wavelength characteristics of a gain, according to a fiber type.

A method of providing in-line Raman amplification in an optical fiber sensing system, including the procedures of generating a probe light having a probe wavelength, transmitting the probe light into an optical fiber, generating at least one Raman pump light at a respective pump wavelength, the pump wavelength being shorter than the probe wavelength, generating at least one Raman seed light at a respective seed wavelength, the seed wavelength being between the pump and probe wavelengths, transmitting the Raman pump light into the optical fiber, transmitting the Raman seed light into the optical fiber and propagating the Raman pump light, the Raman seed light and the probe light along the optical fiber to achieve distributed Raman amplification of signal light produced by the probe light as it propagates along the optical fiber.

A system or a method for optical signal amplification includes determining a target operating gain of an optical amplifier; determining a target maximum gain of the optical amplifier; determining an active fiber section length such that the optical signals are amplified with at most the target maximum gain; determining a core cross-sectional area size of the active fiber section based on a maximum allowable pulse shape distortion and a target maximum energy per pulse such that high-energy pulses with the target maximum energy per pulse are distorted by at most the maximum allowable pulse shape distortion; and determining an operating pumping power of the pumping device below the maximum pumping power such that the optical signals are amplified with the target operating gain.

A method for quantum key distribution includes determining a ratio between a target maximum gain and a target operating gain of an optical amplifier; determining an active fiber section length such that the optical signals with a target maximum signal power are amplified with at most the target maximum gain; determining an operating pumping power of a pumping device below the maximum pumping power such that the optical signals are amplified with a target operating gain according to the determined ratio between the target maximum gain and the target operating gain; and determining a shared key between a first data processing device and a second data processing device by quantum key distribution comprising amplifying the optical signals via the optical amplifier by operating the pumping device at the operating pumping power.

Aspects of the present disclosure describe systems, methods, and structures for providing C-band and L-band transmission exhibiting increased power efficiency by diverting a portion of C-band optical energy to an input of L-band optical amplifiers (C-seeding) while optionally employing circulators to eliminate the need for optical isolators.

A multi-stage optical amplifier has an input port for receiving an optical signal and a relatively short erbium doped optical fiber is coupled to the input port. Complex costly pump feedback is not required as a constant non-varying saturation pump is configured to provide non varying output power pump light of a predetermined wavelength suitable for excitation and full saturation of the erbium ions such that a full population inversion occurs. The length of the short erbium doped fiber and rare earth doping concentration of the erbium doped fiber is such that when pumped by said pump provides amplification of the optical signal of less than 15 dB. Locating a gain flattening filter after the short erbium doped optical fiber provides a relatively flat amplified output signal. Multi-stages of similar short erbium doped fibers pumped and saturated by the same pump signal economically provide increased amplification of the signal and filters after each state flatten the gain.

A multi-stage optical amplifier has an input port for receiving an optical signal and a relatively short erbium doped optical fiber is coupled to the input port. Complex costly pump feedback is not required as a constant non-varying saturation pump is configured to provide non varying output power pump light of a predetermined wavelength suitable for excitation and full saturation of the erbium ions such that a full population inversion occurs. The length of the short erbium doped fiber and rare earth doping concentration of the erbium doped fiber is such that when pumped by said pump provides amplification of the optical signal of less than 15 dB. Locating a gain flattening filter after the short erbium doped optical fiber provides a relatively flat amplified output signal. Multi-stages of similar short erbium doped fibers pumped and saturated by the same pump signal economically provide increased amplification of the signal and filters after each state flatten the gain.