Abstract: A transmission method includes: in a first period, causing a light source to emit light having a first luminance; and in a second period, causing the light source to transmit an optical signal by causing the light source to alternately emit light having a second luminance and light having a third luminance lower than the second luminance.

Abstract: Light signal-based networking, such as LiFi (light fidelity), has become more prevalent. Such networking means provide a bidirectional wireless system that transmits data via LED or infrared light. Embodiments use light-signal-based networking to easily and securely add new information handling systems to an existing network. In one or more embodiments, matching both pre-set light carrier settings and trust data help make the addition of a node to the network quick and secure. In one or more embodiments, additional security and authentication mechanisms (e.g., tunneling, multi-factor authentication, passwords, token+passwords, secure protocols (e.g., Role-Based Access Control (RBAC), Lightweight Directory Access Protocol (LDAP), etc.) may also be used to further strengthen trust for the network, for the new client node, or both. Once trusted, information about the new client may be added to a datastore to allow other nodes in the network access to a listing of trusted nodes.

Abstract: Described herein are techniques for routing communications to a destination node within a LEO satellite network. The techniques may comprise receiving, at a satellite node in a network of satellites, a communication directed to an address for a destination satellite, determining whether the satellite node is the destination satellite, upon determining that the satellite node is the destination satellite, transmitting the communication to a ground station in communication range of the satellite node, and upon determining that the satellite node is not the destination satellite: identifying, via a local routing table, a second satellite node associated with the address for the destination satellite, and forwarding the communication to the second satellite node.

Abstract: An optical transmitter, including a wavelength selector and a plurality of modulator groups, is proposed. Each modulator group includes a plurality of modulators, and operating wavelengths of any two modulators in each modulator group are different. The wavelength selector is configured to: obtain a first beam from a multi-wavelength light source, and generate a second beam based on the first beam, where the second beam includes some of the plurality of wavelengths of the first beam. A modulator in a modulator group of the plurality of modulator groups is configured to modulate to-be-sent data onto a wavelength in the second beam.

Abstract: In various embodiments, the present disclosure includes a system for sending 50 gigabits per second (Gbps), 75 Gbps, and 100 Gbps at 50 gigabaud (GBaud) for passive optical networks (PON) downstream and upstream. The system allows for transmission of three data rates at a single baud-rate while only using 2-bits of information per sample. A motivation for sending three data rates at a single baud-rate is to allow for further granularity in the control of the data-rates for downstream and upstream traffic in a flexible PON system based on the link margin. For example, the system can use non-return-to-zero (NRZ) at 50 GBaud for 50 Gbps and can use four-level pulse-amplitude modulation (PAM-4) at 50 GBaud for 100 Gbps. In addition for 75 Gbps, a double square-8 (DSQ-8) constellation can be used at 50 GBaud.

Abstract: A fault-tolerant quantum computer using topological codes such as surface codes can have an architecture that reduces the amount of idle volume generated. The architecture can include qubit modules that generate surface code patches for different qubits and a network of interconnections between different qubit modules. The interconnections can include “port” connections that selectably enable coupling of boundaries of surface code patches generated in different qubit modules and/or “quickswap” connections that selectably enable transferring the state of a surface code patch from one qubit module to another. Port and/or quickswap connections can be made between a subset of qubit modules. For instance port connections can connect a given qubit module to other qubit modules within a fixed range. Quickswap connections can provide a log-tree network of direct connections between qubit modules.

Abstract: Systems and methods for performing an upstream trace operation are presented. An exemplary method may include obtaining an indication of a new service location of a passive optical network (PON); detecting a physical polyline route, within the PON, from an on-ramp facility corresponding to the new service location to a serving office of the PON, the detecting based on (i) respective geospatial locations of a plurality of optical components of the PON, and (ii) interconnections of the plurality of optical components, and the plurality of optical components including the on-ramp location, a terminal disposed at the serving office, and at least one optical fiber optically connecting the on-ramp location and the terminal; and causing optical services to be delivered from the serving office to the new service location via the detected physical polyline route.

Abstract: A method including transmitting an intensity-modulated light through a mode conditioner to generate a mode-conditioned intensity-modulated light in one or a plurality of launch conditions and transmitting the mode-conditioned intensity-modulated light through a multimode optical fiber under test (FUT) to excite a plurality of modes of the FUT. The method further includes converting the mode-conditioned intensity-modulated light transmitted through the FUT into an electrical signal, measuring, based on the electrical signal, a complex transfer function CTF(f) of the FUT, and obtaining an output pulse based on the measured complex transfer function CTF(f) from one or a plurality of launch conditions and an assumed input pulse using the equation: Pout (t)=?1(CTF(f)*(Pin(t))). Wherein, Pout (t) is the output pulse, ?1(CTF(f)*(Pin(t))) is the inverse Fourier transform of the function CTF(f)*(Pin (t)), and (Pin(t)) is the Fourier transform of the assumed input pulse.

Abstract: An apparatus includes a reception processing unit configured to output a frequency division multiplexed signal obtained from a transmission signal transmitted over the wired communication network, an output control unit configured to output, in a case that apparatus identifying data matches signal specifying data, a frequency band specifying data indicating a frequency band corresponding to the signal specifying data, the apparatus identifying data being for requesting signal quality degradation, and the signal specifying data specifying a carrier signal requesting signal quality degradation among a plurality of carrier signals included in the frequency division multiplexed signal, a disturbing signal generation unit configured to generate a disturbing signal in a frequency band corresponding to the frequency band specifying data output by the output control unit, and a multiplexing unit configured to multiplex the frequency division multiplexed signal and the disturbing signal to output.

Abstract: Methods and apparatus for conveying directionality and distance information from a transmitter to a receiver within the coordinate system of the transmitter. Conveying the directionality and distance information to the receiver may, for example, reduce computational loads at the receiver. The signal from the transmitter may include information for rendering digital content and information indicating the direction and distance of the transmitter, and the receiver may render the digital content using the direction and distance to reduce processing at the receiver. Alternatively, the signal may include pre-rendered content based on the direction to further reduce processing at the receiver.

Abstract: A method/system described herein addresses the intrinsic nonlinearity of electrooptic modulators and the restrictions placed on the signals dynamic range in applications such as data communication and sensing. Linear electro-optic modulation utilizing ring resonator electrooptic modulators is produced over a dramatically wider range of the input signal amplitude, which improves the dynamic range and the amount of information that is transmitted via laser light. A distributed and subranging design “folds” the large dynamic range across multiple linear subranges, with each subrange being addressed using a unique optical wavelength, or a unique optical fiber, or a unique free space path. The subrange within the wide dynamic range of the input signal is captured by the linear portion of the transfer function of a single transfer function. This enables the efficient use of optical links for the transmission and processing of analog and multilevel signals, overcoming the limitations that were hindering progress.

Abstract: According to examples, a channel checker optical time-domain reflectometer (OTDR) may include a laser source to emit a laser beam. An optical switch may be optically connected to the laser source to receive the laser beam and to selectively transmit the laser beam to a circulator that is optically connected to a device under test (DUT). A first coupler may be optically connected to a first photodiode and to the circulator. A second coupler may be optically connected to the first coupler, the optical switch, and a second photodiode.

Abstract: Coherent optical communications technology for recovery of 1D and 2D formatted optical signals. For example, 1D or 2D formatted signals that travel through fiber optic media may be recovered by separating the light into X- and Y-polarization components, rotating one polarization component (e.g., Y-component) into the polarization space of the other component (e.g., Y-component into the X-polarization space), delaying the rotated component enough to avoid destructive interference and combining the delayed component with the undelayed component to form a folded optical signal, which may then be processed as a X-polarized signal.

Abstract: This application describes techniques for testing fiber optic telecommunication systems, such as undersea fiber optic cable systems. Testing terminals may be deployed at a location of terminating equipment for a fiber optic cable. The testing terminals may be operated remotely. The testing terminals may be configured to programmatically test the cable by loading one or more tests and automatically configure the cable's transmitters and receivers based on predetermined loading schemes selected based on the tests to be performed. The testing terminals may iterate over channels and fiber pairs of the cable and may use back-to-back tests to remove artifacts from test results. Using the described techniques, a cable's channels and fiber pairs can be fully characterized in the amount of time afforded for a typical testing schedule, which was not generally possible using conventional testing.

Abstract: A wavelength cross-connect device performs a relay process in which multiple wavelength signal light beams that have been transmitted in multiple bands from a plurality of paths and demultiplexed into optical signals in the respective wavelength bands for each path are amplified, are switched to paths by contention WSSs, and are output to paths on the output side. A WXC unit performs the relay process on an optical signal in a specific wavelength band. An input-side conversion unit that converts a wavelength band other than the specific wavelength band into the specific wavelength band is provided on the input side, and an output-side conversion unit that converts the specific wavelength band after the conversion into the wavelength band prior to the conversion is provided on the output side. A directly-input optical signal in the specific wavelength band is directly output after the relay process at the WXC unit.

Abstract: The disclosed systems, and methods for detecting an improper protection in an optical communication network comprising: i) receiving, by a first Coherent-Optical Time Domain Reflectometer (C-OTDR), a first reflected optical signal from a first optical fiber; ii) receiving, by a second C-OTDR, a second reflected optical signal from a second optical fiber; iii) pre-processing, by a processor, the first reflected optical signal and the second reflected optical signal; iv) determining, by the processor, a category of the first C-OTDR and the second C-OTDR; v) depending upon the category of the first C-OTDR and the second C-OTDR, computing a correlation between the first preprocessed reflected optical signal and the second preprocessed reflected optical signal based on a first correlation computation technique or a second correlation computation technique; and vi) based on the computed correlation, detecting the improper protection in the optical communication network.

Abstract: An optical receiver (100) comprising: a polarisation controller (102) arranged to receive as its input a first modulated optical signal having a first polarisation and an unmodulated optical carrier signal polarisation aligned with the first modulated optical signal, the first modulated optical signal having negligible spectral power density within a predetermined bandwidth, BW, around an optical spectrum of the unmodulated optical carrier signal; optical filter apparatus (104) having a main polarisation mode; and coherent optical receiver apparatus (106), wherein the polarisation controller is arranged to apply polarisation rotations to the first modulated optical signal and the unmodulated optical carrier signal such that their polarisation is aligned to the main polarisation mode of the optical filter apparatus, the optical filter apparatus is arranged to receive and separate the unmodulated optical carrier signal from the first modulated optical signal, and the coherent optical receiver apparatus is arran

Abstract: An optical tracking system includes at least one tracking array for generating and optically transmitting data between 1 and 2,000 MB/s. At least one tracker for optically receiving the optically transmitted data between 1 and 2,000 MB/s is also provided. The tracking system is used not only for tracking objects and sending tracking information quickly but also providing the user or other components in an operating room with additional data relevant to an external device such as a computer assisted device. Orthopedic surgical procedures such as total knee arthroplasty (TKA) are performed more efficiently and with better result with the optical tracking system.

Abstract: Described herein is a solution to address the intrinsic nonlinearity of analog signals and the restrictions this places on the signals dynamic range. The subject matter described herein produces linear electro-optic modulation over a dramatically wider range of the input signal amplitude. This is accomplished by a distributed multiwavelength design that “folds” the large dynamic range across multiple linear subranges, with each subrange being addressed using an optical wavelength. As a result, the subrange within the wide dynamic range of the input signal is captured by the linear portion of the transfer function of a single transfer function. Several physical implementations of this subject are presented herein. This innovation enables the efficient use of optical links for the transmission and processing of analog and multilevel signals, overcoming the limitations that were once hindering progress in this field.

Abstract: A phase difference distribution estimation method includes: receiving an optical signal via a space and detecting a phase of the optical signal; calculating characteristic values related to characteristics of the atmosphere through which the optical signal propagates from the optical signal received in the receiving; estimating a phase difference distribution of an optical signal received after a certain period of time, on the basis of the characteristic values calculated in the calculating; and controlling a phase of an optical signal in the receiving on the basis of the phase difference distribution estimated in the estimating.