Abstract: A wavelength-selectable laser device generally includes an array of laser emitters and a filtered external cavity for filtering light emitted from the laser emitters and reflecting different wavelengths back to each of the laser emitters such that lasing occurs at different wavelengths for each of the laser emitters. Each laser emitter includes a gain region that emits light across a plurality of wavelengths including, for example, channel wavelengths in an optical communication system. The filtered external cavity may include a dispersive optical element that receives the light from each of the laser emitters at different angles and passes or reflects different wavelengths of the light at different angles such that only wavelengths associated with the respective laser emitters are reflected back to the respective laser emitters. By selectively emitting light from one or more of the laser emitters, one or more channel wavelengths may be selected for lasing and transmission.

Abstract: A wavelength-selectable laser device providing spatially-selectable wavelength(s) may be used to select one or more wavelengths for lasing in a tunable transmitter or transceiver, for example, in a wavelength division multiplexed (WDM) optical system such as a WDM passive optical network (PON). The wavelength-selectable laser device uses a dispersive optical element, such as a diffraction grating, to disperse light emitted from a laser emitter and to direct different wavelengths of the light toward a reflector at different spatial positions such that the wavelengths may be selected by allowing light to be reflected from selected spatial position(s) back into the laser emitter. Thus, the reflected light with a wavelength at the selected spatial position(s) is allowed to complete the laser cavity.

Abstract: A modulated optical system with cross-modulation compensation reduces or corrects cross-modulation that might occur at a target frequency range in a multichannel RF signal that modulates a laser. The system detects the cross-modulation, for example, by detecting an envelope of the RF signal or by detecting RF power fluctuations, generates a cross-modulation detection signal, filters the cross-modulation detection signal at the target frequency range, and imparts a compensating cross-modulation to the RF signal in response to the filtered cross-modulation detection signal.

Abstract: In a laser package, a tilted laser causes laser light to be coupled into an optical fiber at an angle relative to a fiber axis of the optical fiber. The tilted laser emits laser light at an angle relative to a lens axis of a lens such that the lens directs and focuses the laser light at the angle relative to the fiber axis. Tilting the laser allows the laser light to be coupled into the optical fiber substantially parallel to or aligned with the core of the fiber while causing back reflection to be directed away from the laser, thereby improving coupling efficiency and minimizing feedback. The tilted laser may be coupled to an angle polished fiber, for example, in a laser package such as a TO can type laser package, a butterfly type laser package, or a TOSA type laser package.

Abstract: A distortion compensation circuit with frequency detection may be used with one or more non-linear elements, such as a laser, to compensate for frequency-dependent distortion generated by the non-linear element(s), for example, in broadband multichannel RF applications. Embodiments of the distortion compensation circuit may include a frequency detector circuit that detects changes in frequency loading conditions in the distortion compensation circuit such that distortion compensation may be adjusted to compensate for distortion under different frequency loading conditions. In a multichannel RF system with multiple channel operation modes, for example, the frequency detector circuit may detect changes in the frequency loading condition as a result of changing operation modes.

Abstract: A distortion compensation circuit including a configurable delay may be used with one or more non-linear elements, such as a laser, to compensate for distortion generated by the non-linear element(s), for example, in broadband RF applications. Embodiments of the distortion compensation circuit may include a primary signal path with a configurable delay segment and a secondary signal path including at least one distortion generator. The configurable delay segment may be selectively configured to provide different delay settings to accommodate different RF loading conditions such that the delayed RF signal on the primary signal path is aligned with the distortion products generated on the secondary signal path when combined to form an RF signal with distortion compensation.

Abstract: A distortion compensation circuit compensates for distortion generated by one or more non-linear elements such as a laser device and may include a primary signal path for carrying an input signal and one or more secondary signal paths for generating distortion. The distortion compensation circuit may also include one or more controllable phase inverters on at least one of the paths. For example, the secondary signal path may include a distortion generator to produce distortion products from the input signal and a signal controlled phase inverter that inverts the phase of the distortion products. The distortion generator and phase inverter may be combined as an invertible distortion generator. The phase inversion may be controlled in response to a phase inversion control signal generated based on one or more parameters such as temperature.

Abstract: A pluggable bi-directional optical transceiver may include: a transmitting laser diode, for transmitting an optical signal according to a received electronic signal; an optical sensor, for receiving the optical signal and for generating the electronic signal according to the received optical signal; a fiber adapter, having a ceramic ferrule with two 8-degree end-face corners; a coupling portion, having three different openings for respectively receiving the transmitting laser diode, the optical sensor, and one end of the ceramic ferrule so an optical axis of a transmitting light of the transmitting laser diode is configured to deflect about 3.8 degrees with an optical axis of the ceramic ferrule; and an engaging portion, having a hollow shell for receiving another end of the ceramic ferrule and an engaging piece surrounding outside the shell for pluggably connecting an external fiber piece.

Abstract: A modulated optical system with anti-clipping reduces or corrects clipping that might occur in the laser as a result of negative spikes or peaks in a multichannel RF signal. The system generally detects an envelope of the RF signal to generate an anti-clipping signal that follows at least a portion of the envelope and prevents one or more negative peaks from causing clipping by adjusting a bias current in response to the anti-clipping signal. The system may also reduce cross modulation by clamping the anti-clipping signal at an anti-clipping limit during lower power periods of the RF signal.

Abstract: Techniques are disclosed for providing bi-directional data services involving a plurality of wavelengths. The data services may be hybrid in nature, including both digital and analog data signals. The techniques may be implemented, for instance, in an optical module, and allow one or more wavelengths to pass-through while other wavelengths are terminated or otherwise diverted. In one example embodiment, the techniques are embodied in a quad-port optical module having two input/output (I/O) ports and pass-through capability for at least one of the wavelengths, add capability for at least one wavelength, and drop capability for at least one wavelength. The module may further include transmit and/or receive capability for one or more signal types. The module can be operatively coupled with a bidi device or other suitable transceiver, to provide modular transmit-receive capability for a desired signal type.

Abstract: A distortion compensation circuit compensates for distortion generated by one or more non-linear elements such as a laser device. The distortion compensation circuit may be used in an optical transmitter, such as a laser transmitter used for forward path CATV applications. The distortion compensation circuit may include a primary signal path and a secondary signal path that receive an input signal. The secondary signal path produces distortion of a magnitude corresponding to the magnitude of, but at an opposite phase to, the distortion generated by the non-linear amplifier. The secondary signal path includes a plurality of distortion sub-paths with each of the distortion sub-paths configured to produce intermodulation distortion products of the same distortion order but for different frequency dependent orders in a time dependent series representative of the distortion produced by the non-linear amplifier.

Abstract: A gain-coupled distributed feedback (DFB) semiconductor laser includes a grating formed by grooves through at least a part of an active region of a laser cavity. The DFB laser may be configured with a substantially pure gain-coupled grating and may be configured to provide facet power asymmetry. The grating may include at least a first-order grating section and a second-order grating section. A lasing wavelength may be obtained at the Bragg wavelength of the second-order grating section by substantially eliminating index coupling in the grating. The first-order grating section may act as a reflector for the lasing wavelength, thereby producing asymmetric power distribution in the laser cavity.

Abstract: Generally, a fixture for securing optoelectronic packages may be used to secure one or more optoelectronic packages for mounting one or more components and/or one or more wires to at least first and second mounting surfaces at different relative angles. The fixture is rotatable between at least first and second mounting positions with a top surface of the fixture being at respective first and second mounting angles relative to a horizontal plane. The fixture may be configured to secure the optoelectronic package(s) for positioning at different mounting angles to facilitate mounting the components and/or wires to the mounting surfaces at the different angles. The fixture may also be configured to be continuously adjustable over a range of angles between the first and second mounting angles.

Abstract: The subject matter disclosed herein relates to a method and/or system for adjusting a thermoelectric cooler.

Abstract: A distortion compensation circuit compensates for distortion generated by one or more non-linear elements such as a laser device and may include a primary signal path for carrying an input signal and one or more secondary signal paths for generating distortion. The distortion compensation circuit may also include one or more controllable phase inverters on at least one of the paths. For example, the secondary signal path may include a distortion generator to produce distortion products from the input signal and a signal controlled phase inverter that inverts the phase of the distortion products. The distortion generator and phase inverter may be combined as an invertible distortion generator. The phase inversion may be controlled in response to a phase inversion control signal generated based on one or more parameters such as temperature. The secondary signal path may also include separate distortion sub-paths to produce frequency independent distortion products and frequency dependent distortion products.

Abstract: The subject matter disclosed herein relates to determining a photosensor operating point.

Abstract: A position finding system and method may be used to find an alignment position of a laser device relative to an optical fiber such as an angled optical fiber. The laser device may be positioned “off-axis” relative to the optical fiber such that light from the laser device is directed at an angle to an end of the optical fiber and coupled into the optical fiber. The position finding system and method may be used to find the alignment position by searching for relative high power positions at different angular orientations of the laser device and calculating coordinates of at least one alignment position from the coordinates of the relative high power positions. The relative high power positions may be positions at which the measured power coupled into the optical fiber by the laser is maximized.

Abstract: A system and method for restoring a clipped signal may be used in an optical receiver that detects a clipped modulated optical signal. The clipped modulated optical signal is detected to produce a clipped electrical signal including a series of clipped negative peaks and corresponding positive peaks. The clipped signal may be corrected by detecting at least one trigger peak preceding one or more clipped negative peaks to be restored and generating a replacement tip signal segment for the clipped negative peak(s) to be restored. The replacement tip signal segment may be combined with the clipped electrical signal such that the replacement tip signal segment coincides with a clipped end of the clipped negative peak to be restored to produce a restored negative peak.

Abstract: A predistortion circuit provides a predistorted input signal that compensates for distortion generated by a non-linear amplifier such as a laser device. The predistortion circuit may be used in an optical transmitter designed for broadband applications, such as a laser transmitter used for forward path CATV applications. The predistortion circuit may include a primary signal path and a secondary signal path that receive an input signal. A second order distortion generator on the secondary signal path generates predistortion of a magnitude corresponding to the magnitude of, but at an opposite phase to, the distortion generated by the non-linear amplifier. The second order distortion generator includes diodes with an adjustable diode bias to control phase, magnitude and/or magnitude/phase versus frequency of the predistortion.

Abstract: Briefly, various embodiments of a pluggable form factor release mechanism are described. For example, but without intending to limit the scope of claimed subject matter, a transceiver module may include the following: a module housing; a bail lever; an actuator; and a spring adjacent to the actuator. The bail lever and the actuator may be movably connected to the module housing in such a manner so that pivoting the bail lever away from the housing engages an end of the actuator to move towards the module housing. The actuator may rotate about a fulcrum with an opposing end of the actuator moving away from the module housing.