Remote terminal field device monitoring using distributed fiber optic sensing (DFOS) comprising a length of optical sensor fiber extending into the remote terminal, said remote terminal including one or more field devices located therein, wherein said length of optical sensor fiber located in the remote terminal includes one or more fiber loops formed in the length of optical sensor fiber, said one or more fiber loops respectively positioned proximate to the one or more field device(s) located in the remote terminal, a DFOS interrogator in optical communication with the optical sensor fiber and configured to generate optical pulses, introduce the generated pulses into the length of optical sensor fiber, and receive backscattered signals from the one or more fiber loops formed in the length of the optical sensor fiber, and an intelligent analyzer configured to analyze DFOS data received by the DFOS interrogator and determine from the backscattered signals, environmental activity occurring at the one or more fiber loops located within the remote terminal; operating the DFOS system and collecting/analyzing/reporting the environmental activity determined at the one or more fiber loops located within the remote terminal.

Remote terminal field device monitoring using distributed fiber optic sensing (DFOS) comprising a length of optical sensor fiber extending into the remote terminal, said remote terminal including one or more field devices located therein, wherein said length of optical sensor fiber located in the remote terminal includes one or more fiber loops formed in the length of optical sensor fiber, said one or more fiber loops respectively positioned proximate to the one or more field device(s) located in the remote terminal, a DFOS interrogator in optical communication with the optical sensor fiber and configured to generate optical pulses, introduce the generated pulses into the length of optical sensor fiber, and receive backscattered signals from the one or more fiber loops formed in the length of the optical sensor fiber, and an intelligent analyzer configured to analyze DFOS data received by the DFOS interrogator and determine from the backscattered signals, environmental activity occurring at the one or more fiber loops located within the remote terminal; operating the DFOS system and collecting/analyzing/reporting the environmental activity determined at the one or more fiber loops located within the remote terminal.

There is provided a method, apparatus and system for determining multipath interference (MPI) in optical communications. It is object of embodiments of the present disclosure to provide an effective, low-cost way of detecting or measuring MPI. To effectively detect and measure the MPI, multiple zero-power gaps are inserted into the transmission signal (optical signal) in time domain. In some embodiments, at least some of the zero-power gaps inserted in the main signal do not overlap the zero-power gaps of the reflection of the main signal. Using the zero-power gaps contained the main signal and the reflection (where applicable), power inside and outside the zero-power gaps are determined. Then, the strength of the MPI is determined based on the determined power inside and outside the zero-power gaps.

A controller for a front-exciting Raman-amplifier that amplifies an optical signal transmitted from one end of an optical fiber to other end by inputting an excitation light to the one end, the controller includes a memory, and a processor coupled to the memory and configured to acquire communication-related information regarding communication of the optical signal in the optical fiber, when the acquired communication-related information does not indicate the communication of the optical signal, set a Raman gain of the front-exciting Raman amplifier based on a first light intensity of an amplified spontaneous scattered light of the excitation light, and when the acquired communication-related information indicates the communication of the optical signal, set the Raman gain based on a second light intensity of the optical signal output from the optical fiber.

A controller for a front-exciting Raman-amplifier that amplifies an optical signal transmitted from one end of an optical fiber to other end by inputting an excitation light to the one end, the controller includes a memory, and a processor coupled to the memory and configured to acquire communication-related information regarding communication of the optical signal in the optical fiber, when the acquired communication-related information does not indicate the communication of the optical signal, set a Raman gain of the front-exciting Raman amplifier based on a first light intensity of an amplified spontaneous scattered light of the excitation light, and when the acquired communication-related information indicates the communication of the optical signal, set the Raman gain based on a second light intensity of the optical signal output from the optical fiber.

The disclosed systems and methods support addition of bands to a multi-band optical interface. The systems and methods can include a multi-band interface device for optical networks. The device can include a multi-band optical amplifier, a C-Band Add/Drop multiplexer, an L-Band Add/Drop multiplexer and an amplifier noise source. The multi-band optical amplifier can be connected to the C-Band Add/Drop multiplexer and connected to the L-Band Add/Drop multiplexer through the amplifier noise source. The amplifier noise source be configured to generate a combination of bulk noise and an input transmission received from the L-Band Add/Drop multiplexer. The gain of the amplifier noise source can depend on the power of the received input transmission. The power of the received input transmission can be increased over a period of time, transitioning the amplifier noise source from acting as a bulk noise source to acting an amplifier.

A system for the Raman amplification of mode-division multiplexed optical signals at the telecom wavelengths in multimode optical fibers, and a method. A mode-division multiplexer (105) is used at the input of a multimode fiber (107) to inject signals (101), and continuous-wave pump waves at lower wavelength (102), on the different transverse modes of the fiber. A second mode-division multiplexer (106) is used at the output of the fiber to extract the amplified signals (103). The amplification of one or more signals is accomplished by inter-modal and intra-modal stimulated Raman scattering occurring between the fiber transverse modes carrying the signals and those carrying the pumps.

A system for the Raman amplification of mode-division multiplexed optical signals at the telecom wavelengths in multimode optical fibers, and a method. A mode-division multiplexer (105) is used at the input of a multimode fiber (107) to inject signals (101), and continuous-wave pump waves at lower wavelength (102), on the different transverse modes of the fiber. A second mode-division multiplexer (106) is used at the output of the fiber to extract the amplified signals (103). The amplification of one or more signals is accomplished by inter-modal and intra-modal stimulated Raman scattering occurring between the fiber transverse modes carrying the signals and those carrying the pumps.

In optical fiber sensors, sensor signals obtained differ according to the circumstances of installation, in locations being observed, of optical fibers serving as sensors, and it is difficult to perform accurate measurements; therefore, a sensor signal processing apparatus according to the present invention includes variation calculation means for receiving a sensor signal based on scattered light of a light pulse propagating through an optical fiber, and calculating a variation of the sensor signal from a reference value; and normalization processing means for normalizing the variation within a predetermined time, and calculating a normalized variation.

In optical fiber sensors, sensor signals obtained differ according to the circumstances of installation, in locations being observed, of optical fibers serving as sensors, and it is difficult to perform accurate measurements; therefore, a sensor signal processing apparatus according to the present invention includes variation calculation means for receiving a sensor signal based on scattered light of a light pulse propagating through an optical fiber, and calculating a variation of the sensor signal from a reference value; and normalization processing means for normalizing the variation within a predetermined time, and calculating a normalized variation.