Abstract: Techniques and devices for depolarizing light and producing a variable differential group delays in optical signals. In one implementation, an input optical beam is split into first and second beams with orthogonal polarizations. One or two optical reflectors are then used to cause the first and second optical beams to undergo different optical path lengths before they are recombined into a single output beam. An adjustment mechanism may used implemented to adjust the difference in the optical path lengths of the first and second beams to produce a variable DGD. When the depolarization of light is desired, the difference in the optical path lengths of the first and second beams is set to be greater than the coherence length of the input optical beam.

Abstract: Devices and techniques that use a polarization controller and a feedback control to the polarization controller to systematically control the polarization of light output from the polarization controller in measuring the polarization dependent loss (PDL) of an optical device or material that receives the light from the polarization controller or the degree of polarization (DOP) of a light beam directed into the polarization controller.

Abstract: Apparatus, systems and techniques for measuring optical spectral property such as the frequency and the optical spectrum of light based on polarization analysis.

Abstract: Optical devices and techniques for using optical polarization of light to transmit through an optical path four times to quadruple a total delay in the light through the optical path.

Abstract: Techniques and devices for depolarizing light and producing a variable differential group delays in optical signals. In one implementation, an input optical beam is split into first and second beams with orthogonal polarizations. One or two optical reflectors are then used to cause the first and second optical beams to undergo different optical path lengths before they are recombined into a single output beam. An adjustment mechanism may used implemented to adjust the difference in the optical path lengths of the first and second beams to produce a variable DGD. When the depolarization of light is desired, the difference in the optical path lengths of the first and second beams is set to be greater than the coherence length of the input optical beam.

Abstract: Devices and techniques that use a polarization controller and a feedback control to the polarization controller to systematically control the polarization of light output from the polarization controller in measuring the polarization dependent loss (PDL) of an optical device or material that receives the light from the polarization controller or the degree of polarization (DOP) of a light beam directed into the polarization controller.

Abstract: This application describes optical monitoring devices and applications in optical systems for monitoring various optical parameters of light, including the signal to noise ratio, the degree of polarization, and the differential group delay (DGD).

Abstract: Devices and techniques for generating and analyzing states of polarization in light using multiple adjustable polarization rotators in various applications.

Abstract: Devices and techniques for generating and analyzing states of polarization in light using multiple adjustable polarization rotators in various applications.

Abstract: The present invention provides a system and method for TCP High Availability. The system concurrently delivers incoming data streams to AMB and SMB, concurrently sends outgoing data streams originated from AMB to SMB and peer routers, synchronizes the incoming and outgoing data streams between AMB and SMB, and accelerates the synchronizations of the incoming and outgoing data streams between AMB and SMB.

Abstract: A system for filtering light propagating in a waveguide is described. The system utilizes an adjustable periodic grating which induces mode coupling of predetermined frequencies of light propagating in the waveguide.

Abstract: This application describes optical monitoring devices and applications in optical systems for monitoring various optical parameters of light, including the signal to noise ratio, the degree of polarization, and the differential group delay (DGD).

Abstract: Apparatus, systems and techniques for optical communication based on polarization division multiplexing (PDM) using an optical monitor channel to facilitate the effective demultiplexing of the two orthogonal signal channels through automatic feedback control on a dynamic polarization controller and a polarization beam splitter.

Abstract: Designs of fiber stretcher apparatus using one or more linear actuators to stretch fiber loops for various applications including variable optical delay lines and devices using such delay lines.

Abstract: Polarimeters based on transversal division of the input beam and use of different polarization elements in different polarization states to change polarizations of different portions of the input beam so that the power levels of the different portions of the input beam can be measured to determine the polarization state of the input beam. A wedged substrate can be used to direct the different portions of the input beam at different directions and a lens can be used to focus these different portions at different locations at a plane.

Abstract: A communications network comprising components configured to implement a method comprising analyzing a path between a first end point and a second end point, and identifying a partial fault along the path is disclosed. Also disclosed is a method for communicating information within a network, the method comprising: defining a path traversing a plurality of nodes, receiving a fault report from an intermediate node, determining whether the fault report affects the path, and responsive to the determination that the fault report affects the path, transmitting the fault report to an upstream or downstream node in the path.

Abstract: This application describes techniques for optical multiplexing and demultiplexing in optical communication systems based on polarization multiplexing of different signal channels.

Abstract: Optical devices and techniques for using optical polarization of light to transmit through an optical path four times to quadruple a total delay in the light through the optical path.

Abstract: This application teaches various implementations of methods and in-line polarimeters with free-space sampling elements to sample four sample beams for determining the polarization state of input light. In one exemplary implementation, a device in this application includes four optical polarization analyzers arranged in series to form an optical path in free space to split four sample beams with four different states of polarization from an input optical beam propagating along the optical path. Each optical polarization analyzer transmits a majority of the input optical beam along the optical path and splits a fraction of the input beam as a respective sample beam. The device also includes four optical detectors respectively positioned in optical paths of the four sample beams to convert the sample beams into four detector signals indicative of optical power levels of the four different states of polarization, respectively.

Abstract: Techniques and devices for monitoring polarization of light using at least two polarization elements where the difference between the outputs of the two polarization elements are used to monitor a change in polarization.