Raman amplifier systems and methods with an integrated Optical Time Domain Reflectometer (OTDR) for integrated testing functionality include an amplifier system, an OTDR and telemetry subsystem, and a method of operation. The OTDR and telemetry subsystem is configured to operate in an OTDR mode when coupled to a line in port and to operate in a telemetry mode when coupled to a line out port. The OTDR and telemetry subsystem enables on-demand fiber testing while also operating as a telemetry channel that is both a redundant optical service channel (OSC) and provides a mechanism to monitor Raman gain over time. The OTDR and telemetry subsystem minimizes cost and space by sharing major optical and electrical components between the integrated OTDR and other functions on the Raman amplifier.

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.

Systems and methods for characterizing an optical fiber performed in part by an optical node (12) in an optical line system (10) include performing one or more measurements to characterize the optical fiber (16, 18) with one or more components (50, 52) at the optical node (12), wherein the one or more components (50, 52) perform functions during operation of the optical node (12) and are reconfigured to perform the one or measurements independent of the functions; and configuring the optical node (12) for communication over the optical fiber (16, 18) based on the one or more measurements. The one or more components can include any of an Optical Service Channel (OSC), an Optical Time Domain Reflectometer (OTDR), and an optical amplifier. The configuring can include setting a launch power into the optical fiber based on the one or more measurements.

Example fiber amplifiers and gain adjustment methods for the fiber amplifiers are described. One example fiber amplifier includes a first power amplifier, a wavelength level adjuster, and a controller, where the first power amplifier is connected to the wavelength level adjuster. The controller includes a first input end and a control output end. The first input end is configured to receive an input optical signal, and the control output end is configured to output a first amplification control signal to the first power amplifier, and output an adjustment control signal to the wavelength level adjuster. The wavelength level adjuster is configured to perform power adjustment on each wavelength in a separate manner based on the adjustment control signal.

Optical network devices, optical receivers, Automatic Gain Control (AGC) circuits, and power detection systems are provided for detecting power of optical signals within an optical communication system. An optical network device, according to one implementation, includes a receiver configured to receive an optical signal. The optical network device also includes a low bandwidth path configured to detect a low-band power component of the optical signal within a channel of interest and a broad bandwidth path arranged in parallel with the low bandwidth path. The broad bandwidth path is configured to detect a broad-band power component of the optical signal within broad-band channels including at least the channel of interest. A power detection output is derived from the low-band power component and the broad-band power component.

Systems and methods for avoiding fiber damage of an optical fiber link are provided. A method, according to one implementation, includes monitoring optical signals transmitted along an optical fiber link from an output port of a first card to an input port of a second card. In response to detecting a fiber disconnection state when an amplifier of the first card is operating in a normal condition, the amplifier of the first card enters a forced Automatic Power Reduction (APR) condition. In addition to potentially reducing the risk of eye damage from laser light emitted from the optical fiber link, the forced APR condition is configured to allow for an uninterrupted debugging procedure. Also, the method includes returning the amplifier of the first card from the forced APR condition back to the normal operating condition after receiving an indication that the fiber disconnection state has cleared.

This application discloses an optical amplifier including a Raman fiber amplifier (RFA), a dynamic gain equalizer (DGE), a filter, an erbium-doped fiber amplifier (EDFA), an RFA gain controller, an EDFA gain controller, and an optical amplifier controller. The optical amplifier controller is configured to provide instructions to and receive feedback from the RFA and EDFA gain controllers. The RFA and the EDFA are configured to amplify an optical signal. The RFA gain controller is configured to control the RFA to adjust a gain. The EDFA gain controller is configured to control the EDFA to adjust a gain. The DGE adjusts insertion loss. The filter is configured to filter an amplified spontaneous emission signal produced in an optical amplification process of the RFA.

An excitation light source apparatus capable of assuring an excellent optical transmission characteristic even at occurrence of a gain tilt is provided. The excitation light source apparatus comprises an excitation light outputting means, a control signal detection means, a control signal detection means, an excitation light control means, and a multiplexing means. The excitation light outputting means outputs excitation light for Raman amplification. The control signal detection means detects a control signal of the excitation light outputting means from beams of WDM signal light transmitted through optical fibers in an upstream direction and a downstream direction. The excitation light control means controls the excitation light outputting means, based on the control signal. The multiplexing means multiplexes the excitation light and each of the beams of the WDM signal light, and outputs the respective multiplexed beams of light to the optical fiber.

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.

An optical link optimization includes receiving detected power outputs from one or more receivers in an optical network, wherein the detected power outputs include both a broad bandwidth power component and a low bandwidth power component; analyzing the detected power outputs to one or more of (1) balance power of a channel of interest for the one or more receivers and associated adjacent channels to a given channel of interest and (2) adjust filtering of the channel of interest for the one or more receivers and the associated adjacent channels to the given channel of interest; and configuring one or more components of the optical network to provide the one or more of (1) balance power and (2) adjust filtering.