Abstract: A mover assembly (16) that moves or positions an object (12) includes a mover output (226), an actuator (230), and a measurement system (20). The mover output (226) is connected o the object (12), and the actuator (230) causes the mover output (226) to rotate about a first axis and move along the first axis. In this embodiment, the measurement system (20) directly measures the movement of the mover output (226) and provides feedback regarding the position of the mover output (226).

Abstract: An optical signal demodulator for demodulating an M-ary phase shift key (PSK) optical signal comprises a plurality of interferometers arranged such that the optical signal is divided between the interferometers. Each interferometer comprises a plurality of interferometer arms, each arm for transmitting a portion of the signal between an input and an output of the interferometer, the interferometer including an optical delay in one arm relative to another arm thereof. The optical delay between arms of an interferometer may be provided by an optical path length difference between the arms. The optical delay between arms of an interferometer may be different for one interferometer to that of another interferometer.

Abstract: A tuneable laser is disclosed, including a gain section with first and second comb reflectors to one side thereof. The two reflectors each provide combs with substantially uniform spacings, the spacings differing as between the combs. Each comb reflector can be tuned so as to shift the reflective peaks of the combs, thus allowing alignment of a single reflective peak at a chosen wavelength which is the same in both combs, forming a supermode. This supermode has an intensity greater than the threshold of the gain section and thus the laser produces an output at that selected wavelength.

Abstract: A modulator circuit (28) for directing a voltage across a modulator element (26) to modulate a beam (20) includes a first inductor L1 that is electrically connected in parallel to the modulator element (26) and a second inductor L2 that is electrically connected in parallel to the first inductor L1 and the modulator element (26). A resonant frequency of the modulator circuit (28) is controllable over a range of between approximately 200 and 380 MHz. Additionally, the modulator circuit (28) can include a third inductor L3 that is electrically connected in parallel to the inductors L1, L2, and the modulator element (26). Further, the modulator circuit (28) can include an added capacitor (546) that is electrically connected in parallel to the inductors L1, L2, and the modulator element (26).

Abstract: In a light (optical) beam steering/sampling system, a matrix inversion control technique is used to decouple the operation of the actuators which drive the steering mirrors. The control technique uses two virtual variables, each having an associated independent feedback loop operating in a non-cross-coupled manner, each variable being associated with one of the two steering mirrors.

Abstract: An optical multi-filter discriminator suitable for treating optical signals from an optical signal source, e.g., a direct modulated laser (“DML”), comprises a first optical filter, a second optical filter optically coupled to the first optical filter, an input port operative to receive optical signals from an optical signal source and oriented to launch the optical signals directly or indirectly to the first optical filter, and an output port oriented to receive optical signals treated by the multiple optical filters and operative to pass the optical signals directly or indirectly to an optical waveguide “downstream” of the discriminator. The first filter is transmissive (i.e., at the angle of incidence received from the input port) of at least a first wavelength band having a first center wavelength and reflective (again, meaning in this instance at the angle of incidence received from the input port) of at least a second wavelength band different from the first wavelength band.

Abstract: An apparatus and method for integrated grating feedback and retro-reflection are disclosed herein. An unitary optical element is designed to provide a feedback output at one end and an ancillary output at an opposite end. A desired output wavelength is determined by the geometry and index of refraction of the unitary optical element.

Abstract: A beam modulator (14) for modulating a beam (20) includes a modulator element (26) and a housing assembly (24). The modulator element (26) is positioned in the path of the beam (20). The housing assembly (24) retains the modulator element (26). The housing assembly (24) can include a housing (234), a first retainer assembly (342), and a second retainer assembly (344). The first retainer assembly (342) flexibly secures the modulator element (26) to the housing (24) and the second retainer assembly (344) fixedly secures the modulator element (26) to the housing (234) with the modulator element (26) positioned between the retainer assemblies (342) (344). With this design, the retainer assemblies (342) (344) can cooperate to retain the modulator element (26) in a fashion that applies a substantially uniform and small pressure across the modulator element (26).

Abstract: Tunable external cavity lasers are used in applications such as interferometry, FM spectroscopy, and optical communications equipment testing. Mode hop free high bandwidth frequency modulation operation is desired in a tunable external cavity laser. This application describes new and novel techniques for controlling the output wavelength of a tunable external cavity laser while suppressing mode hop.

Abstract: A multichannel optical amplifier having an adjustable gain set point is controlled to permit substantially constant gain tilt control during a gain set-point change so that the channel powers are maintained during system modification. To this end the amplifier comprises an erbium doped fibre (EDF) loop and associated pump amplifier for amplifying an optical signal comprising channels of different wavelengths, a variable optical attenuator (VOA) for controlling the gain of the amplifier by applying a loss profile that varies with wavelength so that the different channels are amplified in accordance with a required gain tilt, preferably a zero gain tilt, and a PI controller for applying a gain tilt adaptation profile to compensate for an inherent gain tilt to produce the required gain tilt.

Abstract: Semiconductor laser diodes, particularly high power AlGaAs-based ridge-waveguide laser diodes, are often used in opto-electronics as so-called pump laser diodes for fiber amplifiers in optical communication lines. To provide the desired high power output and stability of such a laser diode and avoid degradation during use, the present invention concerns an improved design of such a device, the improvement in particular significantly minimizing or avoiding (front) end section degradation of such a laser diode and significantly increasing long-term stability compared to prior art designs. This is achieved by establishing one or two “unpumped end sections” of the laser diode. One preferred way of providing such an unpumped end section at one of the laser facets (10, 12) is to insert an isolation layer (11, 13) of predetermined position, size, and shape between the laser diode's semiconductor material and the usually existing metallization (6).

Abstract: A monitoring device for monitoring a light beam comprises a filter, first and second photodetectors, and an optical body. The first photodetector is arranged to detect a first portion of the light beam that is transmitted through the filter, and the second photodetector is arranged to detect a second portion of the light beam that is reflected from the filter. At least one of the portions of the light beam is directed to its respective photodetector by total internal reflection within the optical body. The monitoring device may be a wavelength locker.

Abstract: A high speed optoelectronic subassembly in an optoelectronic package is disclosed that includes a dielectric support having a first electrical trace on a surface thereof and a dielectric member mounted on the surface of the support having a second electrical trace thereon. The support extends laterally a distance greater than the member to form a shelf. A dielectric step is positioned on the shelf abutting an end of the member and a laser is positioned on the shelf adjacent the step so as to be light accessible external to the subassembly. The laser and the step have surfaces equal in height and cooperate to provide a mounting platform. A resistive element is positioned on the mounting platform and electrically connected to the laser, the resistive element and laser being electrically externally accessible through the traces.

Abstract: An improved method is provided for fabricating a polarisation rotator in a rib waveguide having a propagation axis and opposite side walls. The method includes etching a pit in the substrate surface to form a recess in one of the side walls of the waveguide, during formation of the waveguide on the substrate surface, so as to provide an asymmetric waveguide section for imparting polarisation rotation to radiation propagated along the propagation axis. Preferably the pit is formed by a wet etching step forming an upper side surface within the recess that is inclined relative the waveguide side walls, and the waveguide side walls are formed by a dry etching step to extend perpendicularly to the substrate surface. In addition the dry etching step forms a lower side surface adjoining the upper side surface within the recess and tilted relative to the upper side surface.

Abstract: An optical component for gain-flattening multiplexed passband signals amplified with optical pump power, comprises a launch port optical waveguide operative to communicate multiplexed passband signals in a passband wavelength range and optical pump power in a different wavelength range; a thin film demux filter oriented to receive combined multiplexed passband signals and optical pump power from the launch port optical waveguide, and operative to pass the multiplexed passband signals and to reflect the optical pump power; a bypass port optical waveguide operative and oriented to receive and carry optical pump power reflected by the demux filter; a gain-flattening filter positioned to receive from the thin film demux filter and operative to pass the multiplexed passband signals with a desired attenuation profile for gain-flattening; and an output port optical waveguide oriented to receive and operative to carry at least multiplexed passband signals passed by the gain-flattening filter.

Abstract: An optical device comprises a semiconductor structure including first and second ridge waveguides, each waveguide comprising a ridge extending across a surface of the semiconductor structure. The ridge of the first waveguide has a first height above a first region of the surface, and the ridge of the second waveguide has a second, greater, height above a second region of the surface. The semiconductor structure includes a multimode interference (MMI) region situated between the first and second ridge waveguides, which provides a transition between them. At least a part of the MMI region is tapered in width and/or at least a part of the first and/or second ridge waveguide is tapered in width in a direction extending away from the MMI region.

Abstract: The present invention concerns an anti-reflection coating for semiconductor lasers, in particular a coating on the laser facet with advantageous properties resulting in improved reliability and reduced probability of specific breakdowns, especially so-called catastrophic optical damages (CODs). It is a quarter-wave coating with a predetermined reflectivity, preferably between 0 and 10% and consists of or comprises SiNx:H. It is preferably applied by a Plasma-Enhanced Chemical Vapor Deposition (PE-CVD) process whose process parameters are controlled such that a desired optical thickness and refractive index of the coating are achieved. The PE-CVD process may be controlled to result in an Si/N ratio between about 0.5 and 1.5 and/or to produce a coating of essentially amorphous SiNx:H whose density approaches the density of crystalline Si3N4.

Abstract: The invention concerns a guided wave spatial filter (300) for receiving input radiation and outputting corresponding filtered output radiation, the filter comprising first and second waveguide sections (30, L3, L5) connected in series, the sections: (a) mutually matched for transmitting fundamental mode radiation components present in the input radiation therethrough to provide the output radiation; and (b) mutually mismatched for hindering higher-order mode radiation components present in the input radiation from propagating therethrough and contributing to the output radiation. The spatial filter (300) is implemented using rib waveguides (30) for the sections with associated relatively deeply and relatively shallowly etched structures (20, 310, 320) for imparting to the sections their radiation mode filtration characteristics.

Abstract: A second harmonic generation laser system comprising: a non-linear frequency converting medium; and an external cavity pump laser that produces optical energy at a single mode and at a single frequency and that is disposed to provide the optical energy to the non-linear frequency converting medium.

Abstract: A method and assembly for frequency stabilization of an optical signal especially from a laser, the assembly (11) comprising beam splitter (15), a passive frequency discriminator (16), and a pair of photodiodes (17 & 18). The beam splitter (15) in use receives a collimated optical beam (B) and diverts a sample beam (B1) which is directed towards the discriminator (16) which transmits a portion (B2) of said sample beam to one of the photodiodes (17) and reflects a second portion (B3) of said sample beam to the other photodiode (18). A control signal (S3) is derived from the respective intensities of the transmitted and reflected portions of the sample beam, and utilized to operate the electronic control to adjust the frequency of the laser output signal, if required, to maintain a specified frequency.