An apparatus comprising a bidirectional amplifier or node supporting out-of-band signaling may be provided. The apparatus may comprise a first diplexer, a second diplexer, an upstream reverse amplifier, and a downstream Out-of-Band (OOB) amplifier. The first diplexer may comprise a first diplexer band-stop filter and a first diplexer band-pass filter. The first diplexer band-stop filter may be connected between a first diplexer first port and a first diplexer second port. The first diplexer band-pass filter may be connected between the first diplexer first port and a first diplexer third port. The second diplexer may comprise a second diplexer band-stop filter and a second diplexer band-pass filter. The second diplexer band-stop filter may be connected between a second diplexer first port and a second diplexer second port. The second diplexer band-pass filter may be connected between the second diplexer first port and a second diplexer third port.

An apparatus comprising a bidirectional amplifier or node supporting out-of-band signaling may be provided. The apparatus may comprise a first diplexer, a second diplexer, an upstream reverse amplifier, and a downstream Out-of-Band (OOB) amplifier. The first diplexer may comprise a first diplexer band-stop filter and a first diplexer band-pass filter. The first diplexer band-stop filter may be connected between a first diplexer first port and a first diplexer second port. The first diplexer band-pass filter may be connected between the first diplexer first port and a first diplexer third port. The second diplexer may comprise a second diplexer band-stop filter and a second diplexer band-pass filter. The second diplexer band-stop filter may be connected between a second diplexer first port and a second diplexer second port. The second diplexer band-pass filter may be connected between the second diplexer first port and a second diplexer third port.

[Problem] To provide a monitoring system capable of monitoring, without stopping operations for a long period of time, a change of the characteristics of an apparatus to be subjected to characteristic measurement, to which high frequency signals are inputted. [Solution] A signal to be monitored and a reference signal are inputted to an input unit 11, and the input unit inputs one of the inputted signals to an apparatus 15 to be subjected to characteristic measurement. On the basis of an output signal of the apparatus 15 and the reference signal in the cases where the reference signal is inputted to the apparatus, an input/output characteristic calculation unit 12 calculates the input/output characteristics of the apparatus 15. On the basis of calculation results obtained from the input/output characteristic calculation unit 12, a correction result generating unit 13 generates a correction result signal that indicates the results obtained by correcting an output signal of the apparatus 15 in the cases where the signal to be monitored is inputted to the apparatus. On the basis of the correction result signal generated by the correction result generating unit 13, a failure determining unit 14 determines whether the apparatus has a failure.

[Problem] To provide a monitoring system capable of monitoring, without stopping operations for a long period of time, a change of the characteristics of an apparatus to be subjected to characteristic measurement, to which high frequency signals are inputted. [Solution] A signal to be monitored and a reference signal are inputted to an input unit 11, and the input unit inputs one of the inputted signals to an apparatus 15 to be subjected to characteristic measurement. On the basis of an output signal of the apparatus 15 and the reference signal in the cases where the reference signal is inputted to the apparatus, an input/output characteristic calculation unit 12 calculates the input/output characteristics of the apparatus 15. On the basis of calculation results obtained from the input/output characteristic calculation unit 12, a correction result generating unit 13 generates a correction result signal that indicates the results obtained by correcting an output signal of the apparatus 15 in the cases where the signal to be monitored is inputted to the apparatus. On the basis of the correction result signal generated by the correction result generating unit 13, a failure determining unit 14 determines whether the apparatus has a failure.

The present application is directed to a method of short pulse generation. The method includes the step of creating, via electrical circuitry in a master oscillator, a square wave pulse with a predetermined pulse repetition rate. The method includes the step of retiming the square pulse with a clock. The method includes the step of recovering an electrical signal from the retimed square pulse. Further, the method includes the step of sending the recovered electrical signal to a modulator for modulating an optical signal.

An optical coupling element is configured to be positioned between and optically couple a first optical component configured to transmit a light beam, and a second optical component configured to receive light. The optical coupling element comprises a glass coupler body having a receiving side surface and an opposite transmitting side surface. The glass coupler body comprises a converging member configured to reduce divergence of light entering the glass coupler body via the receiving side surface; and a coupling waveguide extending within the glass coupler body between the converging member and an output facet on the transmitting side surface and being configured to transmit light from the converging member to the output facet.

An optical coupling element is configured to be positioned between and optically couple a first optical component configured to transmit a light beam, and a second optical component configured to receive light. The optical coupling element comprises a glass coupler body having a receiving side surface and an opposite transmitting side surface. The glass coupler body comprises a converging member configured to reduce divergence of light entering the glass coupler body via the receiving side surface; and a coupling waveguide extending within the glass coupler body between the converging member and an output facet on the transmitting side surface and being configured to transmit light from the converging member to the output facet.

An optical relay device is provided which is capable of outputting control signal light without equipping a light source for the control signal light and capable of flexibly managing and changing a wavelength of the control signal light in accordance with a state of a network. The optical relay device includes an optical receiving unit that receives a wavelength multiplexed optical signal, a control unit that specifies a first wavelength and outputting notification information, and a processing unit that selects an optical signal having the first wavelength from the received wavelength multiplexed optical signal, applying intensity-modulation in accordance with the notification information to the selected optical signal, adding the intensity-modulated optical signal back to the wavelength multiplexed optical signal, and outputting the wavelength multiplexed optical signal.

An optical relay device is provided which is capable of outputting control signal light without equipping a light source for the control signal light and capable of flexibly managing and changing a wavelength of the control signal light in accordance with a state of a network. The optical relay device includes an optical receiving unit that receives a wavelength multiplexed optical signal, a control unit that specifies a first wavelength and outputting notification information, and a processing unit that selects an optical signal having the first wavelength from the received wavelength multiplexed optical signal, applying intensity-modulation in accordance with the notification information to the selected optical signal, adding the intensity-modulated optical signal back to the wavelength multiplexed optical signal, and outputting the wavelength multiplexed optical signal.

An apparatus comprising a bidirectional amplifier or node supporting out-of-band signaling may be provided. The apparatus may comprise a first diplexer, a second diplexer, an upstream reverse amplifier, and a downstream Out-of-Band (OOB) amplifier. The first diplexer may comprise a first diplexer band-stop filter and a first diplexer band-pass filter. The first diplexer band-stop filter may be connected between a first diplexer first port and a first diplexer second port. The first diplexer band-pass filter may be connected between the first diplexer first port and a first diplexer third port. The second diplexer may comprise a second diplexer band-stop filter and a second diplexer band-pass filter. The second diplexer band-stop filter may be connected between a second diplexer first port and a second diplexer second port. The second diplexer band-pass filter may be connected between the second diplexer first port and a second diplexer third port.