Corning Applied Technologies Corporation

Boston Applied Technologies, Incorporated

Nz Applied Technologies Corp.

Other

Renka Corporation

Qiushui Chen

Paul Melman

Hua Jiang

Yingyin Kevin Zou

Run Zhang

Jing Zhao

Feiling Wang

Gary Y Wang

Dean Z Tsang

Kevin Zou

Hongzhi Zhao

Guanghai Jin

A polarization imaging apparatus measures the Stokes image of a sample. The apparatus consists of an optical lens set, a first variable phase retarder (VPR) with its optical axis aligned 22.5&#xb0;, a second variable phase retarder with its optical axis aligned 45&#xb0;, a linear polarizer, a imaging sensor for sensing the intensity images of the sample, a controller and a computer. Two variable phase retarders were controlled independently by a computer through a controller unit which generates a sequential of voltages to control the phase retardations of the first and second variable phase retarders. A auto-calibration procedure was incorporated into the polarization imaging apparatus to correct the misalignment of first and second VPRs, as well as the half-wave voltage of the VPRs. A set of four intensity images, I, I, Iand Iof the sample were captured by imaging sensor when the phase retardations of VPRs were set at (0,0), (&#x3c0;,0), (&#x3c0;,&#x3c0;) and (&#x3c0;/2,&#x3c0;), respectively. Then four Stokes components of a Stokes image, S, S, Sand Swere calculated using the four intensity images.

Polarization imaging apparatus with auto-calibration

A polarization imaging apparatus measures the Stokes image of a sample. The apparatus consists of an optical lens set, a linear polarizerwith its optical axis, a first variable phase retarderwith its optical axisaligned 22.5&#xb0; to axis, a second variable phase retarderwith its optical axisaligned 45&#xb0; to axis, a imaging sensorfor sensing the intensity images of the sample, a controllerand a computer. Two variable phase retardersandwere controlled independently by a computerthrough a controller unitwhich generates a sequential of voltages to control the phase retardations of VPRsand. A set of four intensity images, I, I, Iand Iof the sample were captured by imaging sensorwhen the phase retardations of VPRsandwere set at (0,0), (&#x3c0;,0), (&#x3c0;,&#x3c0;) and (&#x3c0;/2,&#x3c0;), respectively Then four Stokes components of a Stokes image, S, S, Sand Swere calculated using the four intensity images.

Polarization imaging apparatus

An electro-optic Q-switch for generating sequence of laser pulses was disclosed. The Q-switch comprises a quadratic electro-optic material and is connected with an electronic unit generating a radio frequency wave with positive and negative pulses alternatively. The Q-switch is controlled by the radio frequency wave in such a way that laser pulse is generated when the radio frequency wave changes its polarity

Electro-optic Q-switch

An optical switch for switching an incoming light signal to one of a number of output ports in a polarization independent manner. The optical switch includes a walk-off device, and a compensator which compensates for walk-off distance variations of two polarized beams, with orthogonal polarization directions, associated with the walk-off device.

Fast 1&times;N fiber-optic switch

An apparatus and method for filtering an optical input is disclosed. In an illustrative embodiment, an optical input is split into polarization components along separate paths. The polarization components are then fed into a first electro-optic device that includes a set of electrodes across which a voltage is applied to adjust a wavelength transmission characteristic of the device. A section of the first device positioned between the electrodes preferably has a birefringence that is adjusted depending on the voltage applied across the electrodes. The adjusted components of the optical input are thereafter combined to produce an optical output. Accordingly, the optical input can be attenuated based on the voltage applied to electrodes of the first electro-optic device.

Dynamic optical filter

An optical modulator is provided to control the intensity of a transmitted or reflected light. In a transmission mode, a separator splits arbitrarily polarized light into two polarization rays and one is made to travel a separate path from the other. A recombiner causes the two rays to recombine at an output unless an electro-optic phase retarder changes the polarization of the two rays, in which case, both of them miss the output by an amount which is a function of the voltage on the retarder. A normally-off version with low polarization mode dispersion is obtained by changing the orientation of the recombiner. A normally-on version with low polarization mode dispersion is obtained with a passive polarization direction rotator. Similar results can be obtained in a reflection mode where the input and output are on the same side of the modulator. Versions using a GRIN lens are particularly suited to modulation of light out of and back into fiber-optic cables. The device can be operated as a variable optical attenuator, an optical switch, or a high speed modulator and is insensitive to polarization of the input light. A preferred material for the phase retarder is a hot-pressed ceramic lead lanthanum zirconate titanate composition.

High-speed electro-optic modulator

A polarization transformer includes at least one plate of transparent polycrystalline material which has an optical axis oriented perpendicular to a propagation direction of incident radiation having a first polarization state. The plate includes electrodes for applying an electric field across a plane of the plate perpendicular to the propagation direction so as to provide controlled phase change such that the polarization of radiation transmitted through the polarization transformer is transformed from the first polarization state to a second polarization state. The plate in a preferred embodiment comprises a ferroelectric complex oxide such as lead lanthanum zirconate titanate (PLZT) material. Such a material provides devices that have very fast response (on the order of microseconds) and low insertion loss.

Polarization transformer

In a device having a fiber-optic cables, one that is normally an input and one that is normally an out output for light transmission through the device, a first polarization sensitive deflector encompassing the normal input beam and a second polarization sensitive deflector encompassing the normal output beam is followed by a polarization interchanger that interchanges the polarization of beams traveling from the input to the output and leaves unchanged the polarization of beams traveling from the output to the input. This is, in turn, followed by a third polarization sensitive deflector encompassing the input beam and a fourth polarization sensitive deflector encompassing the output beam. Lastly, a lens having a reflector on the side opposite the input and output fibers reflects light beams from the input to the output and conversely. The deflectors encompassing the input beam are arranged to produce a deflection in one direction and the deflectors encompassing the output beam produce a deflection in another direction at least at a 45&deg; angle to the direction of the deflectors encmpassing the input beam. When light travels backwards from the normal output cable to the input cable, the two-dimensional deflections reduce the light that reach the input cable due to imperfections in the optical components, but the deflectors and interchangers are still arranged to maximize the transmission from the normal input to the output cable.

Growing community of inventors

Medford, MA, United States of America

Qiushui Chen