An optical detection device includes a photocurrent input terminal; a first branch connected to the photocurrent input terminal includes a plural of MOS transistors; a second branch connected to the photocurrent input terminal includes a plural of MOS transistors. The MOS transistors in the first branch and the MOS transistors in the second branch are arranged in a mirror image manner; a control module connected to the first branch and the second branch to turn on or off the MOS transistors in the second branch; a first auxiliary current input terminal connected to the first branch and a second auxiliary current input terminal connected to the first branch, which are used to compensate the current of the MOS transistors in the first branch; a first current output terminal connected to the first branch and the second branch.

An optical detection device includes a photocurrent input terminal; a first branch connected to the photocurrent input terminal includes a plural of MOS transistors; a second branch connected to the photocurrent input terminal includes a plural of MOS transistors. The MOS transistors in the first branch and the MOS transistors in the second branch are arranged in a mirror image manner; a control module connected to the first branch and the second branch to turn on or off the MOS transistors in the second branch; a first auxiliary current input terminal connected to the first branch and a second auxiliary current input terminal connected to the first branch, which are used to compensate the current of the MOS transistors in the first branch; a first current output terminal connected to the first branch and the second branch.

To generate, in an optical transmission device, a response signal corresponding to executed control even when said optical transmission device does not comprise one or both of a main signal photoelectric conversion function and a main signal optical amplification function, an optical transmission device comprises: an extraction unit that outputs, from a first optical signal including a main signal and a control signal, a signal including control information included in the control signal; a control unit that executes control on the basis of the control information; and a response signal output unit that outputs, according to the control, a response signal in a wavelength band different from the main signal.

A method for determining timing information in an optical communication link includes transmitting a falling edge from a transceiver positioned at a near end of the optical communication link and simultaneously starting a first timer at the transceiver positioned at the near end of the link. The transmitted falling edge is received at a transceiver positioned at a far end of the link. A falling edge is transmitted from the transceiver positioned at the far end of the link after a response delay. The transmitted falling edge is received at the transceiver positioned at the near end of the link while the first timer is simultaneously terminated at the transceiver positioned at the near end of the link and the elapsed time is recorded. The total link delay is determined based on the elapsed time.

Differentiating traffic signals from filler channels in optical networks includes obtaining power measurements of optical spectrum on an optical section in the optical network; analyzing the power measurements to differentiate signal type between traffic signals and Amplified Stimulated Emission (ASE) channel holders; and applying appropriate treatment to the optical spectrum based on the signal type. The analyzing is performed locally without any notification from upstream nodes of the optical spectrum.

A method for determining timing information in an optical communication link includes transmitting a falling edge from a transceiver positioned at a near end of the optical communication link and simultaneously starting a first timer at the transceiver positioned at the near end of the link. The transmitted falling edge is received at a transceiver positioned at a far end of the link. A falling edge is transmitted from the transceiver positioned at the far end of the link after a response delay. The transmitted falling edge is received at the transceiver positioned at the near end of the link while the first timer is simultaneously terminated at the transceiver positioned at the near end of the link and the elapsed time is recorded. The total link delay is determined based on the elapsed time.

The present invention relates to a method for optimizing performance of a multi-span optical fiber network. Each span has an associated optical transmission fiber connected to an associated optical amplifier. Gain and output power of the associated optical amplifier are respectively controlled independently. An amplifier noise figure respectively depends on the gain of the associated optical amplifier, with each associated optical amplifier further connected to launch optical signals into a remainder of a corresponding optical transmission line. The method includes the steps of for each span, computing the amplifier noise figure and a non-linear noise generated in the span based on information about the span and using the computed amplifier noise figure and the computed non-linear noise to compute an optimum launch power, and optimizing performance of the multi-span optical fiber network based on the computed optimum launch powers of all spans.

In order to provide an optical transmission device capable of implementing the spectral control of WDM signals while taking into account optical component characteristics, an optical transmission device is provided with: a WSS; a wavelength monitor that outputs a signal expressing a first spectrum, which is the spectrum of the WSS optical output; an optical processing unit that subjects the WSS optical output to prescribed processing; a temperature monitor that outputs a signal indicating the temperature of an optical processing means; and a control unit that receives the input of the signal expressing the first spectrum and the signal indicating the temperature, and controls the transmission characteristics of the WSS on the basis of the first spectrum and the temperature.

An optical transmission device includes a first detector, a generator, a second detector, and a controller. The first detector detects optical output power of an optical signal for each channel for input to a Mach-Zehnder unit that has asymmetric optical waveguides. The generator superimposes, based on the detected optical output power for each of the channels, a dither signal onto an optical signal in a specific channel from among the plurality of channels for input to the Mach-Zehnder unit. The second detector detects an amplitude value of the dither signal superimposed onto the optical signal in the specific channel output from the Mach-Zehnder unit. The controller adjusts a phase difference in the Mach-Zehnder unit such that the amplitude value of the dither signal superimposed onto the detected optical signal in the specific channel is less than a predetermined threshold.

Automatic optical link calibration systems and methods include an optical node with an Optical Add-Drop Multiplexer (OADM) multiplexer including a channel holder source; an optical amplifier connected to the OADM multiplexer and to a fiber span; an Optical Channel Monitor (OCM) configured to monitor optical spectrum before and after the optical amplifier; and a controller configured to obtain data associated with the fiber span including measurements from the OCM, determine settings of the channel holder source needed to meet a target launch power profile for the fiber span, and configure the channel holder source based on the determined settings.