Adtran Gmbh

Leif J Sandstrom

Daniel M Joffe

John Gordon Brooks

Kevin W Schneider

Richard Lee Goodson

Michael D Turner

George Elliott Bekken

Phillip Stone Herron

Vahid Sahebekhtiari

Thomas Frederick Detwiler

Philip David Williams

Darrell Brown

Kevin Gregory Givens

A laser tuning system includes an optical transmitter having a tunable laser that transmits optical signals at various wavelengths to an optical fiber through an optical component, which attenuates a range of wavelengths of the optical signal. An optical detector detects optical returns that have been reflected from the fiber at points beyond the optical component. A tuning control module analyzes the optical returns in order to provide a tuning value for tuning the laser to a desired wavelength. As an example, the laser may be tuned in order to maximize or otherwise increase the amount of optical power passing through the optical component.

Systems and methods for tuning lasers using reflected optical signals

An optical transmission system includes a laser module generating a modulated optical waveform, including both amplitude and frequency modulation, at center frequencies corresponding to different operating temperatures; and an optical shaping filter, with passbands corresponding to the different center frequencies, that converts at least part of the frequency modulation to additional amplitude modulation. The optical transmission system is tuned by: determining a range of temperatures at which the laser module center frequencies are within a passband of the optical shaping filter; setting the laser module to a temperature, within the range of temperatures, at which the modulated optical waveform is within the passband; measuring an average output power of the optical shaping filter; and adjusting the temperature of the laser module to a target temperature, within the range of temperatures, at which an output condition is achieved, based on the average output power and/or extinction ratio of the filtered waveform.

Tuning a multi-channel optical transmission system

An optical transmission system includes a laser module that generates a modulated optical waveform including both amplitude and frequency modulation; and an optical shaping filter that converts at least part of the frequency modulation to additional amplitude modulation. The optical transmission system is tuned by: measuring, based on the amplitude modulation of a filtered waveform output from the optical shaping filter, an average output power of the optical shaping filter; and adjusting a temperature of the laser module to a first temperature at which a target output condition is achieved, including: adjusting the temperature of the laser module to a first target temperature at which the average output power of the filtered waveform satisfies a first output criteria, or adjusting the temperature of the laser module to a second target temperature at which the output power and extinction ratio of the filtered waveform satisfy a second output criteria.

Tuning an optical transmission system

Methods, systems, and apparatus for automatically identifying rogue Optical Network Unit (ONU) are disclosed. In one aspect, an Optical Line Terminal (OLT) determines dark power on a fiber optic link over a period of time. For a given ONU, the OLT determines an optical power of high signals and an optical power of low signals received over the fiber optic link during a timeslot assigned to the given ONU, determines a modified optical power of the high signals and a modified optical power of the low signals based on differences between the optical power of the respective signals and the dark power, determines an extinction ratio based on a ratio of the modified optical power of the high signals relative to the modified optical power of the low signals, and identifies the given ONU as a rogue ONU when the extinction ratio is outside of a specified range.

Automatic rogue ONU detection

Methods, systems, and apparatus for overlaying a passive optical network on a legacy optical access network are disclosed. In one aspect a system includes a legacy optical access network in a copper loop plant. The legacy optical access network provides access to customer premises. The system also includes a gigabit passive optical network (GPON) that is overlaid on the legacy optical access network. A fiber is shared by the GPON and the legacy optical access network. The GPON can provide a plurality of channels on the shared fiber at wavelengths that are separate and independent of wavelengths of the legacy optical access network.

PON overlay on a legacy optical access network

A correlation optical time domain reflectometer (OTDR) provides a correlation sequence that is continuously transmitted along a fiber for testing the fiber for anomalies. Such continuous transmission can result in beat noise that degrades the quality of the measured returns. In this regard, each sample is composed of backscatter returns from many points along the fiber that arrive at the OTDR at the same time. When a subset of these returns have frequency differences that appear in the passband of the OTDR receiver, the constructive and destructive interference of these returns at the OTDR receiver can cause significant low-frequency beat noise in the OTDR signal. An optical transmitter is configured to transmit the correlation sequence through the fiber using a wideband optical signal such that the beat noise is suppressed within the passband of the OTDR receiver, thereby improving the quality of the returns measured by the OTDR.

Optical time domain reflectometer systems and methods using wideband optical signals for suppressing beat noise

An optical communication system comprises a network interface device (NID) having a media converter coupled to an optical fiber of a passive optical network (PON). The media converter converts optical signals from the PON into electrical signals for communication across at least one non-optical channel, such as a conductive or wireless connection, to customer premises equipment (CPE), such as a residential gateway or other customer premises (CP) device. Rather than implementing an optical media access control (optical MAC) layer in the NID, an optical MAC layer for handling PON protocols and management is implemented by the CPE, thereby effectively extending the customer end of the PON across at least one non-optical connection to the CPE. By implementing the optical MAC layer at the CPE, the complexity of the NID is reduced thereby lowering the cost of the NID. In one embodiment, in an effort to further reduce the complexity of the NID, the optical MAC layer is configured to control a laser-on state of an optical transmitter in the NID.

Systems and methods for extending optical network services across non-optical channels

A communication system comprises a passive optical network (PON) having an optical line terminal (OLT) coupled to a plurality of optical network terminals (ONTs) through a power splitter. Each ONT is coupled to the power splitter via a subscriber line. A switch is coupled to each subscriber line, and all of the switches are coupled to a control element. A power element is configured to receive optical signals communicated by the PON and to convert the optical signals into electrical power for use by the control element. The OLT is configured to detect a rogue ONT and to communicate with the control element for opening the switch that is coupled to the subscriber line of the rogue ONT, thereby optically isolating the rogue ONT from the rest of the PON.

Systems and methods for protecting optical networks from rogue optical network terminals

The present disclosure generally pertains to optical communication apparatuses having field-tunable power characteristics. In one exemplary embodiment, an optical communication apparatus has an optical transmitter. The optical transmitter is coupled to logic that receives a user input indicative of a desired transmit mode for the transmitter, and the logic then dynamically tunes the transmitter's output power according to the selected transmit mode. In addition, the optical communication apparatus may have an optical receiver for receiving optical signals. The sensitivity of the receiver is controlled by a bias voltage that is applied to the receiver by the logic. The logic is configured to receive a user input indicative of a desired receive mode and then to tune the receiver's sensitivity via the bias voltage according to the selected receive mode. Accordingly, both the transmitter and receiver of an optical communication apparatus can be tuned in the field to operate in a desired range, and a field technician can therefore utilize the same optical communication apparatus in any of a variety of applications.

Field-tunable devices for optical communication

An optical communication system has a power dissipating element that is thermally coupled to an optical transmitter. The currents supplied to the transmitter and the power dissipating element are controlled such that the sum of such currents is constant. Accordingly, temperature fluctuations in the transmitter due to patterns in the transmitted data are prevented or at least reduced, thereby reducing thermal tails on measurements. In one exemplary embodiment, a light source is used as the power dissipating element, and the output of such light source is beneficially used to probe another optical fiber or to enhance the OTDR performance or analysis.

Systems and methods for reducing thermal tails on optical time domain reflectometer (OTDR) measurements

A small form factor pluggable (SFP) device has an embedded optical time domain reflectometer (OTDR) for detecting anomalies along an optical fiber. The SFP device has a plurality of optical subassemblies (OSAs) that are used to transmit an optical data signal at a first wavelength, transmit an optical OTDR signal at a second wavelength, and receive an optical data signal at a third wavelength. The OTDR signal is effectively isolated from the data signals based on wavelength, and samples of returns of the OTDR signal are analyzed to detect at least one anomaly along the optical fiber.

Optical communication devices having optical time domain reflectometers

N optical transceivers are each connected to a respective electronic module in one-to-one relation such that a respective one electronic module controls a respective one optical transceiver. An electronic switch matrix provides cross-connect capability between the P redundant electronic modules and N electronic modules to the N optical transceivers. A system controller determines when an active N electronic module has failed, and configures the electronic switch matrix to switch a P redundant electronic module into the optical transceiver to which the failed electronic module was connected. A system switch module redirects traffic and routing information, under the direction of the system controller, from the failed module to the newly activated redundant module so that the redundant module assumes the functionality of the failed module.

Optical communications system having redundant electronic modules for optical transceivers using switch matrix

An optical communications system includes a MSAP and an optical transceiver mounted at the MSAP that communicates over an optical network to at least one optical network terminal (ONT). A first electronic module is operatively connected to the optical transceiver and configured to control the optical transceiver and mounted at the MSAP separate from the optical transceiver. A redundant second electronic module is supported within the MSAP and mounted separate from the optical transceiver. A Mux/Demux module interconnects and supports the first and second electronic modules to form an integral unit and mounted at the MSAP separate from the optical transceiver. The Mux/Demux module is configured to switch the second electronic module into communication with the optical transceiver upon failure of the first electronic module.

Growing community of inventors

Madison, AL, United States of America

Leif J Sandstrom