Abstract: A method and apparatus for controlling a piezo-electric actuator coupled to a driven member is disclosed. The piezo-electric actuator is responsive to waveforms with asymmetrical voltage/current profiles on the rising and falling edge to effect consistent and cumulative movement of the driven member in one of two directions throughout the reciprocations of the piezo-electric actuator. The waveforms are digitally generated from a stored set of numbers or a function for generating the set of numbers. The numbers correspond with the discrete digital values associated with the desired waveforms for moving the driven member in either of at least two directions. The controller may be used to drive more than one piezo-electric actuator. The controller may include responsiveness to a feedback of the position of the driven member to accurately position the driven member.

Abstract: Apparatus and associated method for aligning optical components including lenses, filters, lasers, fiber optics, etc. The apparatus aligns a first optic element and a second optic element and includes a frame and a sleeve. The frame defines a frame bore along a longitudinal axis thereof. The sleeve defines an eccentric bore configured to contain the first optic element or the second optic element. The sleeve is rotatably coupled in the frame bore to align the first optic element with the second optic element in a plane intersected by the longitudinal axis.

Abstract: The present invention provides an optical multimeter for use in calibrating and testing optical components. The optical multimeter includes an optical analog/digital signal generator for delivering an output beam over a wide range of frequencies, duty cycles and amplitudes. The optical signal generator includes a tunable laser. The tunable laser exhibits a small form factor, due in part to a novel wavelength control process which utilizes an open loop system to maintain precise output wavelength control, without the requirement of either a wavelength or position feedback device.

Abstract: An optical isolator includes a first stage configured to refract a light ray applied in a forward direction into a first ray and a second ray. A second stage rotated 90° with respect to the first is configured to refract said first and second rays in a substantially parallel manner. The isolator is configured such that the first ray comprises an e-ray with respect to the first stage and an o-ray with respect to the second stage, and the second ray comprises an o-ray with respect to the first stage and an e-ray with respect to the second stage, thereby substantially reducing the effects of polarization mode dispersion.

Abstract: An isolator is disclosed that features a single birefringent correction element. The correction element is configured to eliminate differential group delay and walk-off simultaneously.

Abstract: A method and apparatus for multiplexing/de-multiplexing optical signals is disclosed. The disclosed devices do not require active components. The devices may be used on their own or as part of a larger system such as a multi-stage mux/demux, an optical switch, or router. The optical device includes a linear polarizer, wave plates and a beam displacer/combiner. The wave plates optically couple to the linear polarizer. The wave plates rotate both odd and even channel components of an optical beam between a linear and an orthogonal relationship depending on the propagation direction. Each wave plate has a selected length and index of refraction determinative of a free spectral range which correspond to a spacing between adjacent gridlines of the selected wavelength grid. Each of the wave plates is tuned to even symmetry with the selected wavelength grid.

Abstract: An optical polarization beam splitter comprises a first optical fiber having an end defining a first optical axis, a second optical fiber having an end defining a second optical axis, and a third optical fiber having an end defining a third optical axis parallel to and spaced apart from the second optical axis. A collimating lens is disposed along the first optical axis positioned to form a collimated optical beam from the first optical fiber. A focussing lens is disposed along a path of the collimated optical beam. A birefringent walk-off crystal has a first face adjacent to the focussing lens and a second face located at a focal plane of the focussing lens and in contact with the ends of the second and third optical fibers.

Abstract: An optical receiver may include a photodector defined on a multilayer semiconductor structure. A first electrode may be formed by at least two substantially concentric conductive rings electrically coupled to one another and to a portion of a first layer of the multilayer semiconductor structure. A second electrode may be coupled to a second layer of the multilayer semiconductor structure and configured to transfer current generated by the photodetector in response to optical emissions. A method of fabricating such an optical receiver is also disclosed.

Abstract: Disclosed is a fiber optic coupler which includes a fused, stretched, and twisted biconical tapered region; a first pair of fiber pigtail ends extending from a first end of said biconical tapered region; a second pair of fiber pigtail ends extending from a second end of said biconical tapered region; and polarization dependent loss preclusion means disposed within said biconical tapered region. Further disclosed is a method for forming the polarization insensitive coupler as described.

Abstract: A modular approach to the design of motion modules, e.g., positioning elements, is disclosed which allows a single positioning element to be integrated into a number of multi-axis configurations through combination with other basic positioning elements all of which share a modular interlocking feature. The motion module includes a base and a mobile stage. The base includes an exterior surface on which a first interconnector is located. The mobile stage includes an exterior surface and a second interconnector. The mobile stage is rotary or linearly positionable with respect to the base The second interconnector is located on the exterior surface of the mobile stage, The first and the second interconnector are mutually engagable With second and first interconnectors of other motion modules for stackable interconnection therebetween.

Abstract: An optical polarization beam splitter comprises a first optical fiber having an end defining a first optical axis, a second optical fiber having an end defining a second optical axis, and a third optical fiber having an end defining a third optical axis parallel to and spaced apart from the second optical axis. A collimating lens is disposed along the first optical axis positioned to form a collimated optical beam from the first optical fiber. A focussing lens is disposed along a path of the collimated optical beam. A birefringent walk-off crystal has a first face adjacent to the focussing lens and a second face located at a focal plane of the focussing lens and in contact with the ends of the second and third optical fibers.

Abstract: An interferometer and related methods for wavelength monitoring are disclosed. The interferometer may be used for the wavelength monitoring or as part of a wavelength feedback and control circuit for an optical signal source. The device operates by creating an output beam on which constructive and destructive optical interference may be detected. The optical interference is generated by a monochromatic beam split into a first beam traversing a stationary path and a second beam traversing a path of variable length. The first and second beams are then recombined to create constructive/destructive interference which may be measured by a detector and correlated with a processor to determine the output wavelength of the optical source. The maximum and minimum of the variable path length are precisely controlled due to use of a micro-positionable semiconductor retroreflector or mirror.

Abstract: The present invention provides an apparatus for passively stabilizing the tuning element in tunable lasers. Lasers stabilized using the passive stabilization of the tuning element exhibit reduced mode hop and increased wavelength stability during temperature variations of the laser or surrounding environment. The stabilization makes the laser suitable for a broad range of applications including optical signal generators and optical multimeters.

Abstract: An automatic fiber pigtailing machine (AFPM) is disclosed. The AFPM provides precise coupling between a fiber pigtail and an optoelectronic (OE) device based on the fidelity of signal transfer across a junction between the fiber and OE device. The AFPM uses a positioning system with a high frequency closed loop optical feedback of a modulated signal to/from the device under assembly (DUA). Local/global maximums in the fidelity of the modulated signal are correlated with relative orientations/alignment/positions of the various components of the DUA to determine the preferred orientation/alignment/positions between the various components for the completed assembly. In an embodiment of the invention the fiber optic extends from a first surface of a generally rectangular package and the electrical interface to the OE device is defined on a surface orthogonal to the first surface.

Abstract: The present invention provides an optical signal generator for use in calibrating and testing optical components. The optical signal generator utilizes a tunable laser in conjunction with a novel modulation circuit to output an analog/digital optical signal. The modulator circuit combines a low-frequency, closed loop power control with a separate digital modulator. The output beam of the tunable laser may be modulated over a wide range of frequencies, duty cycles and amplitudes. Circuitry is also provided for modulation of an analog signal onto the output.

Abstract: Disclosed are optical circulators including a first beam displacer/combiner, a first nonreciprocal rotator, a first beam angle turner, a second beam angle turner, a second nonreciprocal rotator, and a second beam displacer/combiner, together with methods of using the optical circulators and telecommunications systems including the optical circulators.

Abstract: The present invention provides a continuously-tunable external cavity laser (ECL) with a compact form factor and precise tuning. A novel interference filter which may be used to tune the ECL provides an absence of mode-hopping and reduced feedback from both spurious interference and reflections in the external cavity. A novel tuning mechanism is disclosed which provides for mechanical FM tuning of a wide range ECL tuning elements such as: an interference filter, a diffraction element, and a retroreflector. A novel feedback circuit is disclosed which provides closed loop feedback for selecting output wavelength in a laser.

Abstract: An optical polarization beam splitter comprises a first optical fiber having an end defining a first optical axis, a second optical fiber having an end defining a second optical axis, and a third optical fiber having an end defining a third optical axis parallel to and spaced apart from the second optical axis. A collimating lens is disposed along the first optical axis positioned to form a collimated optical beam from the first optical fiber. A focussing lens is disposed along a path of the collimated optical beam. A birefringent walk-off crystal has a first face adjacent to the focussing lens and a second face located at a focal plane of the focussing lens and in contact with the ends of the second and third optical fibers.

Abstract: A multi-position optic mount is disclosed which provides for automatic movement of an optic element between an engaged position, in which the optic element intersects an optical path, and a disengaged position, in which the optic element avoids an optical path. The optic mount may be used for a broad range of optical elements including: lenses, filters, etalons, gratings, retroreflectors, wave guides, fiber optics, lasers, photo-detectors, etc. A unique activation capability is provided in which an active actuator and passive actuator are utilized to move the mount between the engaged and disengaged positions.

Abstract: Disclosed are optical circulators possessing a longitudinal axis, the optical circulator including a first and second walk-off crystals optically coupled in a substantially equivalent optical distance, cascaded walk-off configuration, together with systems including such circulators, and methods of circulating optical signals.