Abstract: An optical system can include a mirror that reflects incoming light to a sensor for detection. The position and/or orientation of the mirror can be controlled to reflect incoming light from different locations and/or directions. Position and/or orientation of the mirror may be tracked and/or detected by an optical position sensor. The position sensor can transmit a beam to a reflector on the mirror, and the reflected beam can be received by the position sensor. Characteristics of the reflected beam can be measured to determine the position and/or orientation of the mirror. For example, the beam can be used for interferometric and/or intensity measurements, which can then be correlated with a position and/or orientation of the mirror.

Abstract: An optical system can include a mirror that reflects incoming light to a sensor for detection. The position and/or orientation of the mirror can be controlled to reflect incoming light from different locations and/or directions. Position and/or orientation of the mirror may be tracked and/or detected by an optical position sensor. The position sensor can transmit a beam to a reflector on the mirror, and the reflected beam can be received by the position sensor. Characteristics of the reflected beam can be measured to determine the position and/or orientation of the mirror. For example, the beam can be used for interferometric and/or intensity measurements, which can then be correlated with a position and/or orientation of the mirror.

Abstract: A recording system employing a magneto-resistive (MR) element senses a resistance value of the MR element and generates one or more MR resistance (MRR) signal values based on the sensed MR element resistance value. The MRR signal values might be, for example, current or voltage values proportional or inversely proportional to the MR element resistance value. The MRR signal values might be employed to control one or more of: i) a unity gain bandwidth of a bias loop for the MR element, ii) an MR read head preamplifier low corner frequency, and iii) a slew rate across the MR element.

Abstract: Use of a depletion mode MOSFET to protect differential terminals of a disk drive read head transducer from an electrostatic discharge event, wherein MOSFET source and drain terminals are connected to the differential terminals. The MOSFET is normally “on” such that a conductive path is provided between the differential signal terminals during assembly of the transducer into a disk drive data storage system and during periods when the transducer is inoperative. The conductive path, limits the differential voltage between the terminals that is generated by a current pulse of an ESD event. The MOSFET is gated off during operation of the disk drive to permit a differential read signal, representing the read data bits, to be developed between the differential terminals.

Abstract: User data is read from a medium having servo data and user data encoded thereon. The user data is read with a read/write head that is operable in a write mode and a read mode. Servo data is read in a time window following a transition from write mode to read mode, with a frequency passband that has a first low frequency corner. User data is read from the medium after expiration of the time window, with a frequency passband that has a second low frequency corner that is lower than the first low frequency corner.

Abstract: The present invention provides a method and apparatus, such as an integrated circuit, to control the extinction ratio of a semiconductor laser and maintain the extinction ratio substantially constant at a predetermined level. Apparatus embodiments include a semiconductor laser, a modulator, a photodetector, and an extinction ratio controller. The semiconductor laser is capable of transmitting an optical signal in response to a modulation current. The modulator is capable of providing the modulation current to the semiconductor laser, with the modulation current corresponding to an input data signal. The photodetector, which is optically coupled to the semiconductor laser, is capable of converting the optical signal into a photodetector current. The extinction ratio controller, in response to the photodetector current, is capable of adjusting the modulation current provided by the modulator to the semiconductor laser to generate the optical signal having substantially a predetermined extinction ratio.

Abstract: The present invention provides a method and apparatus, such as an integrated circuit, to control the optical midpoint power level and the extinction ratio of a semiconductor laser and maintain the optical midpoint power level and the extinction ratio substantially constant at corresponding predetermined levels. Apparatus embodiments include a semiconductor laser, a modulator, a photodetector, an optical midpoint controller, and an extinction ratio controller. The semiconductor laser is capable of transmitting an optical signal in response to a modulation current. The modulator is capable of providing the modulation current to the semiconductor laser, with the modulation current corresponding to an input data signal. The photodetector, which is optically coupled to the semiconductor laser, is capable of converting the optical signal into a photodetector current.