A system and method for efficient optical signal amplification with system monitoring features are provided. For example, an optical repeater may include two different 4-port thin-film gain flattening filters (TF-GFFs), which may be connected to provide a high-loss loop-back (HLLB) path in the optical repeater for system monitoring. The 4-port TF-GFF may have four different ports and may integrate the functionalities of a conventional GFF and a coupler into a single component, thereby increasing power efficiency of the optical repeater.

A system and method for efficient optical signal amplification with system monitoring features are provided. For example, an optical repeater may include two different 4-port thin-film gain flattening filters (TF-GFFs), which may be connected to provide a high-loss loop-back (HLLB) path in the optical repeater for system monitoring. The 4-port TF-GFF may have four different ports and may integrate the functionalities of a conventional GFF and a coupler into a single component, thereby increasing power efficiency of the optical repeater.

Aspects of the present disclosure describe distributed fiber optic sensing (DFOS) systems, methods, and structures that advantageously overcome problems encountered when operating DFOS systems over operational telecommunications facilities namely, cross-phase modulation, and uneven amplitude profiles through the use of a novel constant amplitude coded DFOS employing suppressed out-of-band signaling.

Aspects of the present disclosure describe distributed fiber optic sensing (DFOS) systems, methods, and structures that advantageously overcome problems encountered when operating DFOS systems over operational telecommunications facilities namely, cross-phase modulation, and uneven amplitude profiles through the use of a novel constant amplitude coded DFOS employing suppressed out-of-band signaling.

An optical transmission apparatus includes a multiplexing unit multiplexing signal light of a main signal, and dummy lights of odd channel and an even channel emitted using first and second dummy light sources, respectively, a detection unit detecting abnormality of the first and second dummy light sources, and a control unit performing addition control. The addition control includes control in such a way that dummy light of an even channel emitted using the first dummy light source is additionally multiplexed with the signal light, when no abnormality is found in the first dummy light source and an abnormality of the second dummy light source is detected, and that dummy light of an odd channel emitted using the second dummy light source is additionally multiplexed with the signal light, when no abnormality is found in the second dummy light source and an abnormality of the first dummy light source is detected.

An optical transmission apparatus includes a multiplexing unit multiplexing signal light of a main signal, and dummy lights of odd channel and an even channel emitted using first and second dummy light sources, respectively, a detection unit detecting abnormality of the first and second dummy light sources, and a control unit performing addition control. The addition control includes control in such a way that dummy light of an even channel emitted using the first dummy light source is additionally multiplexed with the signal light, when no abnormality is found in the first dummy light source and an abnormality of the second dummy light source is detected, and that dummy light of an odd channel emitted using the second dummy light source is additionally multiplexed with the signal light, when no abnormality is found in the second dummy light source and an abnormality of the first dummy light source is detected.

A transmission device includes: a memory; and a processor coupled to the memory and configured to: transmit or receive an optical signal; filter an electrical electric field signal that indicates electric field information of the optical signal; calculate a transmission characteristic of filtering of the electric field signal and set the transmission characteristic in the filter on a basis of a narrowing amount of a wavelength band of the optical signal transmitted through a transmission line and a narrowing amount of the wavelength band when a state of the transmission line is changed on a basis of transmission line information regarding the transmission line of the optical signal; and set a transmission parameter of the optical signal according to quality of the electric field signal filtered by the filter.

A transmission device includes: a memory; and a processor coupled to the memory and configured to: transmit or receive an optical signal; filter an electrical electric field signal that indicates electric field information of the optical signal; calculate a transmission characteristic of filtering of the electric field signal and set the transmission characteristic in the filter on a basis of a narrowing amount of a wavelength band of the optical signal transmitted through a transmission line and a narrowing amount of the wavelength band when a state of the transmission line is changed on a basis of transmission line information regarding the transmission line of the optical signal; and set a transmission parameter of the optical signal according to quality of the electric field signal filtered by the filter.

A method of detecting radiation from a source and a radiation detection system embodying the principles of the method are described. The method comprises: positioning a detector to receive radiation from the source; applying a multiplexing transformation to radiation from the source to create complexity in three dimensions in the pattern of radiation from the source; receiving a plurality of responses each being a response to an interaction with incident radiation occurring within the detector; determining, for each of the plurality of responses, a characteristic of the interaction, wherein the characteristic comprises at least a position in three dimensions of the interaction within the detector; processing the said plurality of responses in accordance with the determined position in three dimensions of each interaction within the detector and drawing inferences therefrom regarding the pattern of radiation from the source.

A system (e.g., an optical amplifier) comprising gain fibers (e.g., Bismuth-doped optical fiber) for amplifying optical signals. The optical signals have an operating center wavelength (λ0) that is centered between approximately 1260 nanometers (˜1260 nm) and ˜1360 nm (which is in the O-Band). The gain fibers are optically coupled to pump sources, with the number of pump sources being less than or equal to the number of gain fibers. The pump sources are (optionally) shared among the gain fibers, thereby providing more efficient use of resources.