An optical receiver includes an optical filter that transmits signal light to be received from wavelength-multiplexed signal light, a light source that outputs local oscillation light, a 90-degree hybrid circuit that causes the local oscillation light output from the light source to interfere with the signal light transmitted through the optical filter to output interference signal light, a converter that converts the interference signal light into an electrical data signal, a spectrum detector that detects a frequency spectrum of the electrical data signal based on the electrical data signal, and a controller that controls a center frequency of a passband of the optical filter based on a shape of the frequency spectrum.

Disclosed herein are methods, devices, and system for beam forming and beam steering within ultra-wideband, wireless optical communication devices and systems. According to one embodiment, a free space optical (FSO) communication apparatus is disclosed. The FSO communication apparatus includes a semiconductor optical device configured to have a transient response time of less than 500 picoseconds (ps), a lens, and a first band select filter.

A system comprises a transmitter that generates a combined signal including a first group of optical signals and a second group of optical signals, the first group of optical signals comprising M+X number of optical signals in a first polarization mode, the second group of optical signals comprising N number of optical signals in a second polarization mode, wherein the number of N and M optical signals comprise payload signals, where the X number of optical signals comprises at least one first pilot signal. The system may further include a receiver comprising a polarization recovery device that receives the combined signal and that recovers, from the combined signal, the first group of optical signals with the first polarization mode and the second group optical signals with the second polarization mode based on feedback indicative of at least one signal characteristic of the at least one first pilot signal.

In one embodiment, an intensity modulated (IM) direct detection (DD) optical receiver using a photonic integrated circuit (PIC) with an array of semiconductor optical amplifiers (SOAs) for flexible chromatic dispersion compensation (CDC) is provided. The PIC comprises an 1:N optical splitter to split an input optical signal into N copies; an array of N semiconductor optical amplifiers (SOAs) to receive the N optical outputs from the optical splitter; an array of optical delay lines to receive the outputs from the N SOAs, wherein the delay coefficients for the array of optical delay lines are {0, T, 2T, . . . (N-1) T}, where T =1/2B, where B is the system symbol rate, and each optical path with odd index (1, 3, 5, . . .N-1) from the N optical paths includes a 90-degree phase-shifter; and an optical N:1 coupler to re- combine all N optical paths. A method for automatically controlling a PIC based on the feedback signal from the Rx DSP in an optical receiver is also provided.

A system for the Raman amplification of mode-division multiplexed optical signals at the telecom wavelengths in multimode optical fibers, and a method. A mode-division multiplexer (105) is used at the input of a multimode fiber (107) to inject signals (101), and continuous-wave pump waves at lower wavelength (102), on the different transverse modes of the fiber. A second mode-division multiplexer (106) is used at the output of the fiber to extract the amplified signals (103). The amplification of one or more signals is accomplished by inter-modal and intra-modal stimulated Raman scattering occurring between the fiber transverse modes carrying the signals and those carrying the pumps.

An optical amplifier module is configured as a multi-stage free-space optics arrangement, including at least an input stage and an output stage. The actual amplification is provided by a separate fiber-based component coupled to the module. A propagating optical input signal and pump light are provided to the input stage, with the amplified optical signal exiting the output stage. The necessary operations performed on the signal within each stage are provided by directing free-space beams through discrete optical components. The utilization of discrete optical components and free-space beams significantly reduces the number of fiber splices and other types of coupling connections required in prior art amplifier modules, allowing for an automated process to create a “pluggable” optical amplifier module of small form factor proportions.

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.

Disclosed herein are methods, devices, and system for beam forming and beam steering within ultra-wideband, wireless optical communication devices and systems. According to one embodiment, a free space optical (FSO) communication apparatus is disclosed. The FSO communication apparatus includes an array of optical sources wherein each optical source of the array of optical sources is individually controllable and each optical source configured to have a transient response time of less than 500 picoseconds (ps).

Methods for providing flammability protection for plastic optical fiber (POF) embedded inside avionics line replaceable units (LRUs) or other equipment used in airborne vehicles such as commercial or fighter aircrafts. A thin and flexible flammability protection tube is placed around the POF. In one proposed implementation, a very thin (100 to 250 microns in wall thickness) polyimide tube is placed outside and around the POF cable embedded inside an LRU or other equipment. The thin-walled polyimide tube does not diminish the flexibility of the POF cable.

A data storage system is disclosed that includes a recirculating loop storing data in motion. The data may be carried by a signal via the loop including one or more satellites or other vessels that return, for example by reflection or regeneration, the signals through the loop. The loop may also include a waveguide, for example an optical fiber, or an optical cavity. Signal multiplexing may be used to increase the contained data. The signal may be amplified at each roundtrip and sometimes a portion of the signal may be regenerated.