A method for forming a hybrid active electronic and optical circuit (103) using a lithography mask (6312) is disclosed. The hybrid active electronic and optical circuit (103) includes an active electronic device and at least one optical device on a Silicon-On-Insulator, SOI, wafer (102). The SOI wafer (102) includes an insulator layer (104) and an upper silicon layer (106). The upper silicon layer (106) includes at least one component of the active electronic device and at least one component of the optical device. The method includes projecting the lithography mask (6312) onto the SOI wafer (102) in order to simultaneously pattern the component of the active electronic device and the component of the optical device on the SOI wafer (102).

Integrated optical/electronic circuits and associated methods of simultaneous generation thereof

A method and apparatus for compensating for written-in repeatable runout in a disc drive is provided. Compensation values are determined through an iterative learning process in which parameters of the learning process such as learning gain, servo loop gain, etc. are functions of the iteration number. The learning process also employs a nominal double integrator model of an actuator of the disc storage system. The learning process is also a function of a zero-phase low-pass filter.

Repeatable runout compensation using a learning algorithm with scheduled parameters

A method and apparatus for compensating for repeatable run-out errors in a disc drive is disclosed. The compensation is created by determining transfer function values for a servo loop in the drive as well as a sequence of repeatable run-out values for a portion of a disc. The repeatable run-out values are divided by respective transfer function values to produce compensation values that are inverse transformed to produce time-domain compensation values. These time-domain compensation values are injected into the servo loop to compensate for repeatable run-out errors.

Compensation for repeatable run-out error

A disc storage system is provided which includes a servo control loop for compensating for repeatable runout. Repeatable runout is compensated using table entries of the form Comp Value(k+1)=Comp Value(k)+KΦ(z)RRO(k), where K is a learning rate; k is iteration number Φ(z) is a filter and RRO(k) is the repeatable runout error. Further, ρ(jω)=|1−KΦ(jω)/(1+PC(jω)|<1 needs to be satisfied, where PC(jω) is an open loop frequency response of the servo loop. The filter can comprise a order filter.

Repeatable runout compensation using iterative learning control in a disc storage system

An optical head device includes a light source for emitting light; a collection optical system for collecting the light emitted by the light source to an information memory medium including at least one of a track having a mark or a space selectively arranged, and a track having a prescribed groove; a light detector having a plurality of detection areas for receiving the light reflected by the information memory medium and outputting a signal in accordance with a light amount of the light received; a division element for dividing the light reflected by the information memory medium and allowing the light to be received by the light detector; a switch element for receiving a first signal and a second signal, which are respectively obtained in accordance with the reflected light incident on a first prescribed area and a second prescribed area of the division element and outputting either one of the first signal or the second signal, the first and second prescribed areas being obtained by dividing the division element along at least one division line; and an information reproduction signal generator for receiving the signal output by the switch element and generating information recorded on the track. The switch element outputs either one of the first signal and the second signal in accordance with a distance and e positional relationship between a light collection point of the light output from the collection light system and the track.

Optical head device, inclination detection apparatus using the same, and optical information processing apparatus using the same

A circuit for electronically compensating for optical and mechanical instabilities induced into the focus control and tracking control servo circuits of an optical disk apparatus. The circuit contains a filter and a variable gain amplifier for passing a tracking error signal compensation component at a selected frequency within the range of frequencies in which mechanical resonance is significant and at a magnitude equal to the focus error signal component at that frequency. The result is the electronic elimination of optical feedthrough at mechanically resonating frequencies. A calibration circuit establishes the compensation component magnitude for each optical disk inserted into the apparatus.

Focus and tracking servo decoupling system

Image contrast enhancement, high lateral resolution, and height information are obtained with induced polarization evanescent imaging using a solid immersion lens. Experiments are conducted by imaging features on a patterned Si substrate. Imaging theory is used to predict optimum orientation of high-spatial-frequency samples, and a topographical image is derived from the induced polarization image through a calibration procedure. A numerical aperture of 1.5 is used in the experiment. Height accuracy of +/-2 nm is demonstrated with a known sample.

Evanescent imaging with induced polarization by using a solid immersion lens

A high-speed maskless lithography tool is described for fabricating diffractive optical elements and computer-generated holograms. The system has the capability to write gray-scale features and is also used for inspection of the sample after fabrication.

Maskless Lithography Tool for Fabrication and Inspection of Diffractive Optical Elements and Computer Generated Holograms

A magnetooptical disk recording device has a far-field detector for detecting radial position of a laser beam with respect to tracks on the disk. The far-field detector has a reference line dividing first and second photo detectors. The reference line is centered radially with respect to center lines of the tracks. The reference line is also center lengthwise to be tangentially center with respect to a tangential point on the track. The detector is adjustable both radially and tangentially. The tangential adjustment is based upon sensing two low reflective calibration marks on the disk that indicate centering the laser beam, hence the track tangent point, on the reference line. The calibration is based upon obtaining minimum noise in the detector output signal that signifies that the laser beam is centered on the length of the detector reference line. The calibration marks are in a mirror area disposed at one radial extremity of the disk. The marks are radially elongate and disposed in a radially outward diverge with respect to each other. The marks are disposed at 45 degrees with respect to two circumferentially spaced apart radial lines of the disk.

Calibrating an optical detector to minimize noise from undesired perturbations in disk surfaces

The astigmatic-focusing/push-pull tracking-error detection method is an elegant and sensitive optical servo technique. Unfortunately the formation of error signals far from either line focus of the astigmat (for relaxing alignment tolerances and broadening the servo’s acquisition range) gives rise to undesired diffraction effects in the focus servo channel owing to track crossings of the pregrooved disk by the optical stylus, especially if certain aberrations are present. These undesired effects are given several names: pattern noise, optical servo cross talk, and feedthrough. By combining two astigmatic lenses and their associated detectors, one can configure a differential variant of the astigmatic technique. This double-astigmatic method greatly reduces pattern noise caused by the presence of spurious astigmatism oriented with its line foci at ±45° to the disk tracks. In this paper we present numerical modeling and experimental data that demonstrate the effectiveness of this focusing/tracking technique in feedthrough suppression.

Characterization of a novel focusing/tracking technique with increased feedthrough immunity for optical-disk applications: the double-astigmatic method

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