Abstract: A device for measuring spectrum of light includes a differential group delay (DGD) device positioned to receive light under measurement and to produce output light with a DGD value representing a difference in the group delay between two orthogonal optical polarizations of the light under measurement. An optical detector is positioned to receive the output light from the DGD device to measure a state and a degree of polarization of the output light. A processing device receives and processes measurements of the state and the degree of polarization from the optical detector. A probe light source produces probe light. An optical sensor receives the probe light and interacts with the probe light at a resonance wavelength of the optical sensor. A processing unit processes the optical spectrum of the returned probe light to extract information on a parameter to change the resonance wavelength.

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, systems and techniques for optical communication are provided based on polarization division multiplexing (PDM) to use an optical monitor channel at a distinct optical monitor wavelength to monitor optical polarization fluctuation and polarization mode dispersion during the transmission from the transmitter to the receiver to facilitate the effective demultiplexing of the two orthogonal signal channels at the receiver through automatic feedback control on a dynamic polarization controller and a polarization beam splitter.

Abstract: Techniques and devices for measuring the distribution of polarization crosstalk in birefringence optical media including polarization maintaining fiber based on suppressing the number and magnitude of ghost interference peaks.

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: Techniques, devices and applications of polarization stable lasers to provide laser operations against changes, variations or fluctuations in optical polarization in a laser cavity.

Abstract: Systems, apparatus and methods for characterizing linear retarders using a waveplate analyzer constructed by polarization rotators. In one implementation of such an analyzer, both the retardation of the waveplate sample and the orientation of optical axis of the waveplate sample can be simultaneously measured.

Abstract: Apparatus and methods for scrambling optical modes in multimode fibers to achieve uniform light distribution in guided multi-mode light for various applications.

Abstract: Systems, devices and techniques for generating and analyzing states of polarization in light using multiple adjustable polarization rotators having different discrete polarization rotation states in various applications.

Abstract: This application describes devices and techniques for dynamically controlling polarization light at one or more locations along the optical transmission path to reduce optical noise and PMD in the optical signal. One device according to an implementation includes a polarization controller to receive an optical signal and operable to control polarization of the optical signal in response to a control signal, a fixed optical polarizer to receive output from the optical polarization controller and to produce an output optical signal, and a circuit to receive a fraction of the output optical signal from the fixed optical polarizer and operable to produce the control signal in response to an output power level of the output optical signal which controls the polarization controller to maximize the output power level.

Abstract: Devices and their operations to use multiple adjustable differential group delay (DGD) elements in various applications including tunable PMD emulators and compensators for producing different PMD profiles with an adjustable average DGD value.

Abstract: Differential group delay (DGD) devices and techniques based on folded optical paths. An in-line polarization monitor can be provided as a feedback for worst-case alignment without using an in-line polarizer. Polarization maintaining retro reflectors can minimize the introduced higher-order polarization effects caused by reflections between folding mirrors or prisms in conventional schemes.

Abstract: Techniques and devices that use polarization rotation and optical interferometry to provide optical spectrum analysis of an optical signal.

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: 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: 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: 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: 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: 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).