An optical amplifier may include an erbium-doped fiber and an optical coupler coupled to the erbium-doped fiber. In some embodiments, a length of the erbium-doped fiber may be selected for an amplification gain applied by the optical amplifier. The optical coupler may be configured to multiplex one or more optical data signals and an optical pump signal from an optical pump onto the erbium-doped fiber such that the erbium-doped fiber may amplify a first continuous range of wavelengths of the optical data signals. The optical amplifier may further include a filter coupled to the erbium-doped fiber and configured to attenuate a second continuous range of wavelengths. In some embodiments, the second continuous range may be less than the first continuous range and positioned within the first continuous range.

A hybrid distributed amplification method based on a random fiber laser generated within erbium fiber with low doping concentration, i.e. weak erbium-doped fiber (WEDF), which includes: Step 1. constructing a fiber link via WEDF; Step 2. generating the random fiber laser based on the fiber link, the pump source, the wavelength division multiplexer and the strong feedback module; Step 3. constructing the spatial equalized gain based on hybrid gain of the erbium fiber and random fiber laser; Step 4. the signal is amplified by the hybrid spatial equalized gain. The present invention solves the typical problem of high laser threshold and low pump conversion efficiency when conventional fiber is used to generate random fiber laser for distributed amplification.

Aspects of the subject disclosure may include, for example, receiving a first optical signal from a first optical network via a first port of the wavelength converter, receiving a second optical signal from a second optical network via a second port of the wavelength converter, modulating the first optical signal with the second light signal to generate a third optical signal, eliminating the first light signal from the third optical signal to generate a fourth optical signal, and transmitting the fourth optical signal through the second optical network. The first optical signal can include a first digital signal modulated onto a first light signal of a first wavelength, the second optical signal can include a second light signal can include a second wavelength different from the first wavelength, and the fourth optical signal can include the first digital signal modulated onto the second light signal. Other embodiments are disclosed.

A method of dynamic change detection using an optical fibre arrangement in disclosed. The optical fibre arrangement can include a forward optical path and a second optical path. The optical fibre arrangement can be configured into a plurality of spans by a plurality of nodes between first and second ends of the optical fibre arrangement. At least one of the nodes includes a feed from the forward path to the second path such that forward propagation of the light signal from the forward path feeds the second path. The method can include transmitting a light signal into the forward path; receiving a response signal from the second path, wherein the response signal includes a loop back signal that includes a light signal fed into the second path via the feed; and detecting dynamic changes along a span associated with the feed from the loop back signal.

An optical reception device includes an optical waveguide substrate that includes a polarization beam splitter that divides reception light into an X polarization component and a Y polarization component orthogonal to the X polarization component, a beam splitter that divides local light, a pair of optical hybrid circuits that causes each of the X polarization component and the Y polarization component to interfere with the divided local light, a first optical waveguide through which the reception light passes, a second optical waveguide through which the X polarization component passes, a third optical waveguide through which the Y polarization component passes, and a fourth optical waveguide through which the local light passes, wherein at least one of the first to fourth optical waveguides is doped with rare earth ions for amplifying light having a predetermined frequency when excitation light is introduced.

According to one embodiment of the present invention, there is provided a photon generating apparatus including: a light source configured to emit light; an optical medium configured to generate a pair of photons from the light; a detector configured to detect one photon from the pair of photons and output a detection time of the photon; a buffer including an optical line and an optical switch disposed on an optical path of the photon, which is one photon except for the photon detected by the detector, of the pair of photons; and a processor configured to output a driving signal which controls the optical switch so that a delay occurs at the optical path using the detection time of the photon detected by the detector.

A method for overlapping spectrum amplification includes receiving an optical signal and splitting the optical signal into a first split signal having a first wavelength band and a second split signal having a second wavelength band. The splitting results in a band gap between the first wavelength band and the second wavelength band. The method further includes delaying the first split signal by a threshold period of time relative to the second split signal and combining the first split signal and the second split signal, resulting in a combined signal having the first wavelength band and the second wavelength band without the band gap therebetween. The path difference between the first split signal along the first signal path and the second split signal along the second signal path is within a threshold multipath interference compensation range.

Methods and systems enable amplifying optical signals using a Bragg reflection waveguide (BRW) having second order optical nonlinearity to generate an optical pump by injection locking. The BRW may also be used for parametric amplification of optical signals using the optical pump. Feedback phase-power control may be performed to maximize output power.

According to one embodiment of the present invention, there is provided a photon generating apparatus including: a light source configured to emit light; an optical medium configured to generate a pair of photons from the light; a detector configured to detect one photon from the pair of photons and output a detection time of the photon; a buffer including an optical line and an optical switch disposed on an optical path of the photon, which is one photon except for the photon detected by the detector, of the pair of photons; and a processor configured to output a driving signal which controls the optical switch so that a delay occurs at the optical path using the detection time of the photon detected by the detector.

A method for overlapping spectrum amplification includes receiving an optical signal and splitting the optical signal into a first split signal having a first wavelength band and a second split signal having a second wavelength band. The splitting results in a band gap between the first wavelength band and the second wavelength band. The method further includes delaying the first split signal by a threshold period of time relative to the second split signal and combining the first split signal and the second split signal, resulting in a combined signal having the first wavelength band and the second wavelength band without the band gap therebetween. The path difference between the first split signal along the first signal path and the second split signal along the second signal path is within a threshold multipath interference compensation range.