Abstract: A body monitor (12) for monitoring a condition of a living being (10) includes (i) a monitor housing (28) that is positioned adjacent to the living being (10); (ii) a first laser source (240) that directs a first output beam (240A) at the living being (10) to generate first photoacoustic waves; (iii) a second laser source (242) that directs a second output beam (242A) at the living being (10) to generate second photoacoustic waves; and (iv) a photoacoustic detector (16) secured to the monitor housing (28). The photoacoustic detector (16) detects the first photoacoustic waves and the second photoacoustic waves to monitor the condition of the living being (10). The output beams (240A) (240B) have a different center wavelength and can be in the mid-infrared range.

Abstract: According to embodiments of the present invention, an external cavity laser includes one or more tuning elements. At least one modulated voltage signal or dither is used to lock the transmission peak of the two tuning elements to each other. The wavelength of the laser also may lock onto the lock transmission peaks. In embodiments in which two dither signals are used, the dither signals may be orthogonal to or independent of each other. The two dither signals may produce two control signals to align the transmission peak of one filter to the transmission peak of another filter and the lasing mode of the laser to the aligned filters.

Abstract: According to embodiments of the present invention, an external cavity laser includes one or more tuning elements. At least one modulated voltage signal or dither is used to lock the transmission peak of the two tuning elements to each other. The wavelength of the laser also may lock onto the lock transmission peaks. In embodiments in which two dither signals are used, the dither signals may be orthogonal to or independent of each other. The two dither signals may produce two control signals to align the transmission peak of one filter to the transmission peak of another filter and the lasing mode of the laser to the aligned filters.

Abstract: Semi-integrated external cavity diode laser (ECDL) designs including integrated structures comprising a gain section, phase control section, and optional modulator section. Each integrated structure includes a waveguide that passes through each of the sections. A mirror is defined in the structure to define one end of a laser cavity. A reflective element is disposed generally opposite a rear facet of the gain section, forming an external cavity therebetween. A tunable filter is disposed in the external cavity to effectuate tuning of the laser. During operation, a modulated drive signal is provided to the phase control section. This modulates an optical path length of the laser cavity, which produces an intensity (amplitude) modulation in the laser output. A detector is employed to produce a feedback signal indicative of the intensity modulation that is used for tuning the laser in accordance with a wavelength locking servo loop.

Abstract: An external cavity laser apparatus and method wherein wavelength or channel selection is carried independently from adjustment of external cavity optical path length. The apparatus comprises a wavelength or channel selector tuner and an external cavity tuner, wherein the wavelength tuner is uncoupled from the external cavity tuner. The tuning mechanisms for wavelength selection and cavity optical path length are configured to operate independently or orthogonally with respect to each other. The wavelength tuner may operate according to a first, channel selection signal, while the external cavity tuner operates according to a second, external cavity adjustment signal. The wavelength tuner and external cavity tuner may operate under the control of the same, or of separate controllers.

Abstract: The present invention provides a tunable laser with a compact form factor and precise tuning to any selected center wavelength of a selected wavelength grid. A novel tuning technique is disclosed which includes tuning the laser to selected passbands, as well as tuning the optical path length of the laser utilizing a variety of tuning elements and a feedback circuit working together.

Abstract: Apparatus and methods usable for wavelength references and measurement of wavelength of a light beam. The apparatus comprise at least two wavelength reference or filter elements positioned in a light beam, each wavelength reference element having a different free spectral range and operable to define a joint free spectral range, and a detector positioned in the beam after the wavelength reference elements. The joint free spectral range provided by the multiple wavelength reference elements results in a joint transmission peak that is centered at a unique wavelength, and maximum optical power detectable from the beam by the detector occurs at the center wavelength of the joint transmission peak.

Abstract: Apparatus and methods for compensation of asymmetric mode pulling in external cavity lasers and the like. An apparatus includes a wavelength locker or etalon device to provide an asymmetric power transfer function and generate a transmission peak or peaks of asymmetric shape. The asymmetry of the transmission peak may be in the form of a steeper slope on the long wavelength side of the peak than on the short wavelength side. The asymmetry of the transmission peak or peaks may be structured to compensate or correct for asymmetric mode pulling effects that arise in laser gain media during single mode laser operation.

Abstract: Prior art wavelength lockers used in tunable laser systems can provide information to ensure that the laser is locked onto a channel, but do not provide information as to which specific channel the laser is locked onto. Embodiments of the present invention include a wavelength locking channel monitor that provides a servo-locking error signal and a channel-identifying signal to allow a tunable laser to be updated to lock to the proper channel. Embodiments of the present invention include wavelength-dependent periodic and/or monotonic filters, which provide monotonically variable finesse and a monotonically variable transmission. Embodiments of the present invention also extracts amplitudes, phases, frequency, and/or modulation depths from a dither introduced in an incident light beam to determine the laser channel and the laser mode within that channel.

Abstract: An external cavity laser apparatus and method wherein wavelength or channel selection is carried independently from adjustment of external cavity optical path length. The apparatus comprises a wavelength or channel selector tuner and an external cavity tuner, wherein the wavelength tuner is uncoupled from the external cavity tuner. The tuning mechanisms for wavelength selection and cavity optical path length are configured to operate independently or orthogonally with respect to each other. The wavelength tuner may operate according to a first, channel selection signal, while the external cavity tuner operates according to a second, external cavity adjustment signal. The wavelength tuner and external cavity tuner may operate under the control of the same, or of separate controllers.

Abstract: The invention pertains to wavelength-agile optical filters suitable for wavelength-division-multiplexed (WDM) optical communications networks. More particularly, the invention pertains to optical filters with a wavelength reference that can be remotely switched to arbitrarily selectable channels on a standard grid, and to re-configurable optical communications networks employing same. The present invention provides a communication apparatus with a tunable filter which may be used in a wide range of applications including tuning an external cavity laser (ECL), selecting a wavelength for an add/drop multiplexer and providing channel selection and feedback for a wavelength locker. The filter may be utilized as a discrete component or in combination with circulators, wavelength lockers and gain medium. The filter may be implemented in whole or in part as part of a gain medium.

Abstract: The invention pertains to wavelength-agile optical filters suitable for wavelength-division-multiplexed (WDM) optical communications networks. More particularly, the invention pertains to optical filters with a wavelength reference that can be remotely switched to arbitrarily selectable channels on a standard grid, and to re-configurable optical communications networks employing same. The present invention provides a communication apparatus with a tunable filter which may be used in a wide range of applications including tuning an external cavity laser (ECL), selecting a wavelength for an add/drop multiplexer and providing channel selection and feedback for a wavelength locker. The filter may be utilized as a discrete component or in combination with circulators, wavelength lockers and gain medium. The filter may be implemented in whole or in part as part of a gain medium.

Abstract: Apparatus and methods that utilize tunable elements to provide for selective wavelength tuning of a light beam. The apparatus comprises a first tunable wavelength selection element having a first adjustable free spectral range, a second tunable wavelength selection element having a second adjustable free spectral range, with the first and second tunable wavelength selection elements configured to define a tunable joint transmission peak. The first and second tunable wavelength selection elements respectively define first and second pluralities of tunable transmission peaks, wherein respective ones of each of the first and second plurality of transmission peaks are aligned to obtain a joint transmission peak that may be adjusted by tuning the wavelength selection elements. The free spectral ranges of the wavelength selection elements are configured to enable a Vernier tuning effect.

Abstract: A laser apparatus wherein all optical components are mounted on a unitary, rigid base. Natural frequency modes of the apparatus are above about 2 kHz. Tuning elements in the apparatus may have natural frequencies greater than about 10 kHz.

Abstract: Systems and methods for probing or evaluating optical loss characteristics associated with lasers by monitoring voltage across a laser gain medium, and a laser and method of laser operation wherein intra-cavity losses are determined by monitoring voltage across a gain medium and wherein the cavity loss profile is adjusted according to the voltage across the gain medium.

Abstract: Prior art wavelength lockers used in tunable laser systems can provide information to ensure that the laser is locked onto a channel, but do not provide information as to which specific channel the laser is locked onto. Embodiments of the present invention include a wavelength locking channel monitor that provides a servo-locking error signal and a channel-identifying signal to allow a tunable laser to be updated to lock to the proper channel. Embodiments of the present invention include wavelength-dependent periodic and/or monotonic filters, which provide monotonically variable finesse and a monotonically variable transmission. Embodiments of the present invention also extracts amplitudes, phases, frequency, and/or modulation depths from a dither introduced in an incident light beam to determine the laser channel and the laser mode within that channel.

Abstract: A micro optical bench for mounting precision aligned optics thereon, and an assembly of precision aligned optical components mounted on an micro optical bench.

Abstract: Apparatus and methods for compensation of asymmetric mode pulling in external cavity lasers and the like. An apparatus includes a wavelength locker or etalon device to provide an asymmetric power transfer function and generate a transmission peak or peaks of asymmetric shape. The asymmetry of the transmission peak may be in the form of a steeper slope on the long wavelength side of the peak than on the short wavelength side. The asymmetry of the transmission peak or peaks may be structured to compensate or correct for asymmetric mode pulling effects that arise in laser gain media during single mode laser operation.

Abstract: External cavity lasers apparatus and methods that allow fast tuning, high wavelength stability, low cavity losses, and form factors that are comparable to solid state, fixed wavelength lasers. The apparatus comprise a gain medium emitting a light beam, a tunable wavelength selection element positioned in the light beam and configured feed back light of a selected wavelength to the gain medium, and a microelectromechanical systems (MEMS) actuator element operatively coupled to the tunable wavelength selection element. The MEMS actuator element may be configured to actuate the tunable wavelength selection element according to a first degree of freedom to select the wavelength of the feedback to the gain medium, and to actuate the actuate the tunable wavelength selection element according to a second degree of freedom to provide phase control of the feedback.

Abstract: A micro optical bench for mounting precision aligned optics thereon, and an assembly of precision aligned optical components mounted on an micro optical bench.