Abstract: An apparatus comprising: a processor for determining if a laser is operating in a single-mode state and for determining the degree to which one of one or more tunable parameters for the laser must be adjusted so that laser operates in a single-mode state if not operating in a single-mode state, wherein the one or more tunable parameters include the following parameters: the laser current and the wavelength of the output light. The apparatus may include a laser and/or a holographic storage medium. Also provided is a method for determining if a laser is operating in a single-mode state and for determining the degree to which one of one or more tunable parameters for the laser must be adjusted so that laser operates in a single-mode state if not operating in a single-mode state.

Abstract: An apparatus comprising: a processor for determining if a laser is operating in a single-mode state and for determining the degree to which one of one or more tunable parameters for the laser must be adjusted so that laser operates in a single-mode state if not operating in a single-mode state, wherein the one or more tunable parameters include the following parameters: the laser current and the wavelength of the output light. The apparatus may include a laser and/or a holographic storage medium. Also provided is a method for determining if a laser is operating in a single-mode state and for determining the degree to which one of one or more tunable parameters for the laser must be adjusted so that laser operates in a single-mode state if not operating in a single-mode state.

Abstract: External cavity laser (ECL) systems and methods for measuring the wavelength of the ECL by using a portion of the positional light received by the position sensitive detector (PSD) to determine the position of a wavelength tuning element (such as a diffraction grating or an etalon), for determining the longitudinal laser mode or power output of the laser from a portion of the laser light received by a beam-shearing mode sensor, and by using a non-output beam(s) from a transmissive diffraction grating in the ECL to monitor the external cavity laser.

Abstract: An apparatus comprising: a processor for determining if a laser is operating in a single-mode state and for determining the degree to which one of one or more tunable parameters for the laser must be adjusted so that laser operates in a single-mode state if not operating in a single-mode state, wherein the one or more tunable parameters include the following parameters: the laser current and the wavelength of the output light. The apparatus may include a laser and/or a holographic storage medium. Also provided is a method for determining if a laser is operating in a single-mode state and for determining the degree to which one of one or more tunable parameters for the laser must be adjusted so that laser operates in a single-mode state if not operating in a single-mode state.

Abstract: A tuning methods of an External Cavity Laser Diode (ECLD), comprises steps of: (1) providing a laser light to a grating so as to tilt the grating to an optical axis of a collimated laser light, (2) adjusting the orientation of the grating relative to the collimated laser light, (3) monitoring singleness of longitudinal mode and optical power of a light emitted from the grating, (4) calculating an orientation of the grating to exhibit intended optical power at which the singleness of longitudinal mode shows at least predetermined value, (5) adjusting the grating orientation or the optical axis of the collimated laser light to the calculated grating orientation.

Abstract: A tuning methods of an External Cavity Laser Diode (ECLD), comprises steps of: (1) providing a laser light to a grating so as to tilt the grating to an optical axis of a collimated laser light, (2) adjusting the orientation of the grating relative to the collimated laser light, (3) monitoring singleness of longitudinal mode and optical power of a light emitted from the grating, (4) calculating an orientation of the grating to exhibit intended optical power at which the singleness of longitudinal mode shows at least predetermined value, (5) adjusting the grating orientation or the optical axis of the collimated laser light to the calculated grating orientation.

Abstract: An apparatus comprising: a processor for determining if a laser is operating in a single-mode state and for determining the degree to which one of one or more tunable parameters for the laser must be adjusted so that laser operates in a single-mode state if not operating in a single-mode state, wherein the one or more tunable parameters include the following parameters: the laser current and the wavelength of the output light. The apparatus may include a laser and/or a holographic storage medium. Also provided is a method for determining if a laser is operating in a single-mode state and for determining the degree to which one of one or more tunable parameters for the laser must be adjusted so that laser operates in a single-mode state if not operating in a single-mode state.

Abstract: External cavity laser (ECL) systems and methods for measuring the wavelength of the ECL by using a portion of the positional light received by the position sensitive detector (PSD) to determine the position of a wavelength tuning element (such as a diffraction grating or an etalon), for determining the longitudinal laser mode or power output of the laser from a portion of the laser light received by a beam-shearing mode sensor, and by using a non-output beam(s) from a transmissive diffraction grating in the ECL to monitor the external cavity laser.

Abstract: The invention provides a polarization controller to set the state of polarization (SOP) of light in an optical fiber. A plurality of piezoelectric squeezers couple with an electronic drive to apply compression forces to the fiber. The drive applies voltage signals to the squeezers and monitors one or more of (a) a voltage across the squeezer, (b) a capacitance change with the fiber, (c) a force applied to the squeezer, (d) a force applied to the fiber, and (e) a resonance of one or more squeezers. Feedback from one or more of (a)-(e) is used to modify the applied voltage signals in control of the SOP.

Abstract: The invention allows for the accurate, real-time readout of the optical frequency of a swept-wavelength laser device by counting the number of fringes of a calibrated etalon that occur as the laser is swept. The distinguishing feature of the present invention is that the etalon fringe signal is phase-locked to a slave signal of a higher multiple frequency. The higher frequency of the slave signal divides the frequency interval of the etalon fringe spacing by the additional frequency multiple. The slave signal therefore generates a scale for optical frequency that is of higher resolution than possible with the etalon alone. The phase-lock also insures that the slave signal tracks monotonic scans of the optical frequency regardless of scan profile. The invention also allows for the precise, real-time control of the optical frequency of a laser during the sweep of the laser.

Abstract: The invention provides a polarization scrambler to rapidly change the state of polarization of light transmitted through a single mode fiber such that a substantial portion of the Poincare sphere is covered. A plurality of piezoelectric squeezers couple with an electronic drive. Each squeezer resonates in response to drive signals from the electronic drive to induce radial compression forces on the fiber. The drive signals remain resonant with each squeezer, at frequencies of about 100 kHz, through a feedback loop for each of the squeezers and the electronic drives. Coverage over the Poincare sphere typically occurs in less than about 100 milliseconds, and preferably less than 1 millisecond.

Abstract: A miniature, fiber-coupled Fabry-Perot interferometer has a piezoelectric transducer coupled to first and second collimating lenses. The collimating lenses collimate and interfere light energy within a gap formed between the lenses as part of the interferometer. Preferably, the lenses are matched mode gradient index lenses. Light energy coupled to the collimating lens is thus collimated and interfered within the gap. The piezoelectric transducer expands or contracts to adjust the gap, thereby adjusting the free spectral range of the interferometer. An input fiber provides input to the interferometer; an output fiber carries processed light energy of the selected free spectral range to external devices and optical systems. Metal coatings may be used to provide a capacitive feedback of lens position to calibrate the gap and, thus, the free spectral range.

Abstract: The invention describes devices and methods for determining the wavelength of coherent optical radiation such as is emitted from a laser source. The apparatus is monolithic with no moving parts and consists of optical components that generate signal periodic in the optical frequency of the coherent radiation detected by the component. Each optical component generates a signal with a different period. Differences between the periods of the signals generated by the optical frequency-dependent optical components provides a means of measuring optical wavelengths over a range far exceeding the free spectral range limitations of conventional interferometers. The method of the present invention allows for measurement of optical frequency with an uncertainty of much less than the period of the optical frequency-dependent optical components forming the apparatus.

Abstract: The invention provides a polarization controller to set the state of polarization (SOP) of light in an optical fiber. A plurality of piezoelectric squeezers couple with an electronic drive to apply compression forces to the fiber. The drive applies voltage signals to the squeezers and monitors one or more of (a) a voltage across the squeezer, (b) a capacitance change with the fiber, (c) a force applied to the squeezer, (d) a force applied to the fiber, and (e) a resonance of one or more squeezers. Feedback from one or more of (a)-(e) is used to modify the applied voltage signals in control of the SOP.

Abstract: The invention provides a polarization scrambler to rapidly change the state of polarization of light transmitted through a single mode fiber such that a substantial portion of the Poincare sphere is covered. A plurality of piezoelectric squeezers couple with an electronic drive. Each squeezer resonates in response to drive signals from the electronic drive to induce radial compression forces on the fiber. The drive signals remain resonant with each squeezer, at frequencies of about 100 kHz, through a feedback loop for each of the squeezers and the electronic drives. Coverage over the Poincare sphere typically occurs in less than about 100 milliseconds, and preferably less than 1 millisecond.

Abstract: A miniature, fiber-coupled Fabry-Perot interferometer has a piezoelectric transducer coupled to first and second collimating lenses. The collimating lenses collimate and interfere light energy within a gap formed between the lenses as part of the interferometer. Preferably, the lenses are matched mode gradient index lenses. Light energy coupled to the collimating lens is thus collimated and interfered within the gap. The piezoelectric transducer expands or contracts to adjust the gap, thereby adjusting the free spectral range of the interferometer. An input fiber provides input to the interferometer; an output fiber carries processed light energy of the selected free spectral range to external devices and optical systems. Metal coatings may be used to provide a capacitive feedback of lens position to calibrate the gap and, thus, the free spectral range.