Method And Device For Monitoring Light
Granted: June 18, 2009
Application Number:
20090154512
A method for monitoring laser light launched into a core of a single mode fiber includes launching a portion of light directly into the cladding about the core. The cladding launched light is a known fraction of the core launched light and can be monitored by placing a detector about the cladding. Detected light including light that was launched into the cladding and has leaked through the cladding is used as a known fraction of light in the core and can be used to control the laser…
Free-Space Integrated Photodetector With Reduced Phase Tracking Error
Granted: May 21, 2009
Application Number:
20090129719
A Mach-Zehnder (MZ) interferometer modulator structure for fiberoptic telecommunications is disclosed in which drift of the operating point can be monitored with a reduced phase tracking error. One or more components of free-space light radiated into the substrate of the MZ modulator are selectively detected with one or more photodetectors. Suitable summing circuits are described for nulling out undesired photocurrent contributions in the photodetector(s) from on-state and off-state…
Front-Illuminated Avalanche Photodiode
Granted: May 14, 2009
Application Number:
20090121305
The present invention provides a front-illuminated avalanche photodiode (APD) with improved intrinsic responsivity, as well as a method of fabricating such a front-illuminated APD. The front-illuminated APD comprises an APD body of semiconductor material, which includes a substrate and a layer stack disposed on a front surface of the substrate. The layer stack includes an absorption layer, a multiplication layer, and a field-control layer. Advantageously, a back surface of the APD body…
Achromatic Converter Of A Spatial Distribution Of Polarization Of Light
Granted: May 14, 2009
Application Number:
20090122402
An achromatic converter of spatial distribution of polarization from a first to a second pre-defined distribution of polarization is described. The converter comprises a plurality of photo-aligned quarter-wave or half-wave liquid crystal polymer layers, wherein the patterns of alignment of the layers are correlated with each other so as to make polarization conversion achromatic. Achromatic polarization vortices can be formed. The polarization conversion efficiencies over 97% have been…
Variable Optical Attenuator
Granted: April 23, 2009
Application Number:
20090103867
A compact variable optical attenuator having optical-tap functionality is described comprising a planar waveguide attenuator, a lens, and a photodetector. Input and output waveguides are located close to the optical axis of the lens, which reduces optical aberrations and insertion loss. The waveguide attenuator works by light absorption with virtually no scattered light present, which improves fidelity of measurements of the tapped optical power by the photodetector. The entire…
Optical Phase Modulator With Monitoring Structure
Granted: April 16, 2009
Application Number:
20090097843
The invention relates to an optical waveguide device that includes a waveguide phase modulator (WPM). A waveguide monitoring structure is coupled optically in parallel with the WPM so as to form a Mach-Zehnder interferometer therewith for producing monitor light indicative of a phase shift imparted by the WPM. The waveguide monitoring structure includes a first optical tap for tapping off a fraction of light entering the first WPM for providing first tapped-off light, a second optical…
Apparatus And Method For Flattening Gain Profile Of An Optical Amplifier
Granted: April 9, 2009
Application Number:
20090091819
A change in loading conditions of fiber amplifiers in an optical communications network causes rapid variations in the gain profile of the amplifiers due to spectral hole burning and stimulated Raman scattering. An apparatus for reducing such gain profile variations is described which monitors optical signal perturbations and reacts by adjusting pump powers of the amplifiers and, or fast variable optical attenuator according to a predetermined function stored in the form of constants in…
External Optical Modulator With Domain Inversion For Providing Constant Chirp Versus Frequency
Granted: April 9, 2009
Application Number:
20090093982
The invention relates to an external optical modulator comprising a Mach-Zehnder having a signal electrode including at least four sections of unequal length to one another positioned over an alternating domain structure in an electrooptic substrate, and including a center section, or center pair of sections disposed asymmetrically between pairs surrounding sections. The surrounding pairs, comprise the two sections adjacent the center section or pair of sections, and each two sections…
Reinforced Glitter
Granted: March 26, 2009
Application Number:
20090081460
The reinforced opaque glitter particles have a substantially uniform shape and size. Each of the particles includes a reflective core supported by a transparent organic substrate and one or more robustness-improving layers for providing rigidity to the particle. Optionally, the particles have lacquer layers at a surface of the particle. One example of a robustness-improving layer is an inorganic transparent protective layer having a thickness of at least 20 nm adjacent directly to the…
Anisotropic Magnetic Flakes
Granted: March 19, 2009
Application Number:
20090072185
The invention relates to anisotropic, reflective, magnetic flakes. In a liquid carrier and under influence of an external magnetic field, the flakes attract to one another side-by-side and form ribbons which provide higher reflectivity to a coating and may be used as a security feature for authentication of an object.
Optical Fiber Holder And Heat Sink
Granted: March 5, 2009
Application Number:
20090060444
An optical fiber holding device is disclosed having an optical fiber held therein. The device has a base with a spiral channel in an upper surface holding and housing the optical fiber. The channel has a first location where the fiber enters leading to a plurality of turnings for holding the optical fiber wrapped therearound at another end a second location where the fiber exits the channel wherein the bend radius of the optical fiber housed within the spiral channel is at least 2 cm.…
Component Assembly And Fabrication Method
Granted: February 26, 2009
Application Number:
20090052857
The present invention relates to a component assembly and to a method of fabricating such a component assembly. The component assembly includes a substrate, a mount attached to the substrate, and a component attached to the mount with solder by melting the solder with light from a light source. The mount is composed of a ceramic material having properties advantageous for soldering using a light source. As a first property, the ceramic material is optically absorptive to enable the mount…
Scanning Spectrometer With Multiple Photodetectors
Granted: February 19, 2009
Application Number:
20090046288
A scanning optical spectrometer with a detector array is disclosed, in which position of focused spot of light at the input of a dispersive element such as arrayed waveguide grating (AWG) with a slab input, is scanned using a micro-electro-mechanical (MEMS) tiltable micromirror so as to make the dispersed spectrum of light scan over the detector array coupled to the AWG. Sub-spectra recorded using individual detectors are concatenated by a processor unit to obtain the spectrum of input…
Avalanche Photodiode With Edge Breakdown Suppression
Granted: January 22, 2009
Application Number:
20090020782
The invention relates to an avalanche photodiode having enhanced gain uniformity enabled by a tailored diffused p-n junction profile. The tailoring is achieved by a two stage doping process incorporating a solid source diffusion in combination with conventional gas source diffusion. The solid source diffusion material is selected for its solubility to the dopant compared to the solubility of the multiplication layer to dopant. The solid source has a diameter between the first and second…
Mesa-Type Photodetectors With Lateral Diffusion Junctions
Granted: January 22, 2009
Application Number:
20090020841
The present invention relates to a stable mesa-type photodetector with lateral diffusion junctions. The invention has found that without resorting to the complicated regrowth approach, a simple Zn diffusion process can be used to create high-quality semiconductor junction interfaces at the exposed critical surface or to terminate the narrow-bandgap photon absorption layers. The invention converts the epi material layers near or at the vicinity of the etched mesa trench or etched mesa…
Mounted Semiconductor Device And A Method For Making The Same
Granted: January 8, 2009
Application Number:
20090008773
A method for mounting a semiconductor device onto a composite substrate, including a submount and a heat sink, is described. According to one aspect of the invention, the materials for the submount and the heat sink are chosen so that the value of coefficient of thermal expansion of the semiconductor device is in between the values of coefficients of thermal expansion of the materials of the submount and the heat sink, the thickness of the submount being chosen so as to equalize thermal…
Non-Etched Flat Polarization-Selective Diffractive Optical Elements
Granted: January 8, 2009
Application Number:
20090009668
A polarization-selective diffractive optical element includes a liquid crystal polymer film supported by a substrate. The liquid crystal polymer film includes an array of pixels, each pixel encoded with a fixed liquid crystal director such that each liquid crystal director is aligned in a common plane perpendicular to the liquid crystal polymer film and provides a predetermined pattern of out-of-plane tilts. A size of the pixels in the array and the predetermined pattern are selected…
Method And Apparatus For Referencing A MEMS Device
Granted: January 8, 2009
Application Number:
20090009752
A method and an apparatus for calibrating a MEMS actuator of a hybrid MEMS-PLC optical switch or router is described. Two calibrating waveguides, embedded monolithically adjacent to the waveguides that provide the PLC output functions, are used for referencing a MEMS mirror tilt angle by maximizing optical coupling of light, reflected off the MEMS mirror, into one or each of the two calibrating waveguides. The input light is provided by either a waveguide carrying a live optical signal,…
Semiconductor Laser With Narrow Beam Divergence
Granted: January 8, 2009
Application Number:
20090011531
The invention relates to a method of reducing vertical divergence of a high-power semiconductor laser with a negligible threshold current and conversion efficiency penalty. The low divergence is achieved by increasing the thickness of the n-cladding layer in an asymmetric laser diode stack structure, to a value ranging from 1 to 4 times the laser mode size measured at 10% level. The divergence may be tuned by adjusting the n-cladding layer parameters in an area of the tail the optical…
Near Halfwave Retarder For Contrast Compensation
Granted: January 1, 2009
Application Number:
20090002579
Contrast compensation for a liquid crystal display projection system is provided with a trim retarder that includes a single-layer retarder element that has an in-plane retardance that is shifted from a zero-order half-wave at a predetermined wavelength by a predetermined amount. This near half-wave plate provides similar contrast compensation and azimuthal angle sensitivity to conventional relatively low-magnitude trim retarders, yet is readily fabricated with inorganic birefringent…
