Abstract: A reflective optical element includes a reflective surface comprising a multitude of discrete recessed and non-recessed areas arranged along the reflective surface. The discrete areas are arranged to approximate a desired phase function (typically modulo 2?) and are smaller than an operational wavelength in order to provide a range of phase delays needed to adequately approximate the desired phase function. Effecting at least partial reflow of one or more optical media or reflective materials can smooth the morphology of the reflective surface so as to reduce unwanted diffraction or scattering.

Abstract: A differential signal offset adjustment circuit may include a first circuit for receiving a first one of a differential input signal and generating a first one of a differential output signal with positive offset based on a differential offset signal. The circuit may further include a second circuit for receiving a second one of a differential input signal and generating a second one of a differential output signal with a negative offset based on the differential offset signal.

Abstract: In one example embodiment, an integrated silicon photonic wavelength division demultiplexer includes an input waveguide, an input port, a plurality of output waveguides, a plurality of output ports, a first auxiliary waveguide, and a plurality of auxiliary waveguides. The input waveguide may be formed in a first layer and having a first effective index n1. The input port may be optically coupled to the input waveguide. The output waveguides may be formed in the first layer and may have the first effective index n1. Each of the output ports may be optically coupled to a corresponding output waveguide. The first auxiliary waveguide may be formed in a second layer below the input waveguide in the first layer. The first auxiliary waveguide may have a second effective index n2 and may have two tapered ends, and n2 may be higher than n1.

Abstract: Various polarization rotator splitter (PRS) configurations are disclosed. In an example embodiment, a system includes a PRS that includes a silicon nitride (SiN) rib waveguide core that includes a rib and a ridge that extends vertically above the rib, the SiN rib waveguide core having a total height hSiN from a bottom of the rib to a top of the ridge, a rib height hrib from the bottom of the rib to a top of the rib, a rib width wrib, and a top width wSiN of the ridge. The rib width wrib varies along at least a portion of a length of the SiN rib waveguide core.

Abstract: An example embodiment includes an electromagnetic radiation (EMR) shield. The EMR shield is configured to reduce EMR from escaping a host device. The EMR shield includes a structure, two or more module-grounding tabs, and multiple fingers. The structure is configured to substantially surround two or more adjacent transceiver modules positioned in an opening defined in a bezel. The two or more module-grounding tabs extend from the structure. Each of the module-grounding tabs is configured to contact one of the transceiver modules. The fingers extend from the structure and are configured to contact the bezel at multiple contact areas substantially surrounding the opening.

Abstract: A circuit and method in an amplifier circuit for filtering a DC offset in differential input signals and inserting a programmable adjustable crosspoint offset in differential output signals. An amplifier circuit includes a differential amplifier circuit configured to amplify differential input signals into differential output signal. The amplifier circuit further includes a feedback circuit coupled between the differential output signals and the differential input signals. The feedback circuit is configured to generate a programmably adjustable crosspoint offset in the differential output signal and a programmably adjustable cutoff frequency of the feedback circuit. An amplifier method includes amplifying differential input signals into differential output signals, generating a programmably adjustable crosspoint offset in the differential output signal, and generating a programmably adjustable cutoff frequency of a feedback circuit between the differential output signals and the differential input signals.

Abstract: An optical waveguide may include a silicon portion and a silicon nitride portion positioned over the silicon portion. The silicon portion may include a taper that decreases a width of the silicon portion. The optical waveguide may include a transition between a loaded single mode or multimode waveguide to a single mode waveguide. The silicon nitride portion may confine optical signals traveling through the optical waveguide in the silicon portion.

Abstract: In an embodiment, an optoelectronic module includes a printed circuit board (PCB) and a lens block. The printed circuit board (PCB) includes at least one of an optical transmitting or receiving array. The lens block may be configured for directly coupling light between one of the optical transmitting or receiving array to optical fibers in an optical cable. A method may include directly coupling light between one of an optical transmitting or receiving array and a lens block, and further coupling the light through the lens block directly to an optical fiber of an optical cable externally coupled to the optoelectronic module.

Abstract: A printed circuit board may include an aluminum nitride (AIN) substrate that includes an AIN thin film and a layer of high-frequency polymer as a carrier substrate of the AIN thin film. The AIN substrate forms a first layer of the printed circuit board. The AIN substrate comprises a heat spreader that laterally spreads out heat from a heat sink on the printed circuit board to form a thermal dissipation path parallel with a signal path on the printed circuit board. The printed circuit board may include a main substrate aligned to and bonded with the AIN substrate. The main substrate may include one or more additional layers of the printed circuit board.

Abstract: Described herein is a wavelength selective switch (WSS) type optical switching device (1) configured for switching input optical beams from input optical fiber ports (3, 5 and 7) to an output optical fiber port (9). Device (1) includes a wavelength dispersive grism element (13) for spatially dispersing the individual wavelength channels from an input optical beam in the direction of a second axis (y-axis). The optical beams propagate from input ports (3, 5 and 7) in a forward direction and are reflected from a liquid crystal on silicon (LCOS) device (11) in a return direction to output port (9). The input optical beams are transmitted through a port selecting module (21), which provides polarization diversity to device (1) and provides capability to restrict optical beams returning from LCOS device (11) from being coupled back into input ports (3, 5 and 7).

Abstract: An optical assembly includes a first grating device configured to: receive a light beam that includes an optical signal with a particular wavelength from a fiber; and change a propagation direction of the optical signal according to the particular wavelength of the optical signal. The optical assembly also includes a second grating device configured to: receive the optical signal outputted from the first grating device; change the propagation direction of the optical signal according to the particular wavelength of the optical signal; and direct the optical signal onto a grating coupler. The first grating device and the second grating device are configured to satisfy a plurality of configuration constraints.

Abstract: A distributed reflector (DR) laser may include a distributed feedback (DFB) region and a distributed Bragg reflector (DBR). The DFB region may have a length in a range from 30 micrometers (?m) to 100 ?m and may include a DFB grating with a first kappa in a range from 100 cm?1 to 150 cm?1. The DBR region may be coupled end to end with the DFB region and may have a length in a range from 30-300 ?m. The DBR region may include a DBR grating with a second kappa in a range from 150 cm?1 to 200 cm?1. The DR laser may additionally include a lasing mode and a p-p resonance frequency. The lasing mode may be at a long wavelength side of a peak of a DBR reflection profile of the DBR region. The p-p resonance frequency may be less than or equal to 70 GHz.

Abstract: An embodiment includes a track and hold amplifier device. A device may include an emitter follower transistor coupled to each of an input and an output. The device may also include a charging node coupled between the output and a voltage supply, wherein the charging node is also coupled to the input via the emitter follower transistor. Further, the device may include a cascode switch coupled to each of the input and the output. The cascode switch may be configured to cause the emitter follower transistor to operate in a conductive state and charge the charging node during a track mode. The cascode switch may also be configured to cause the emitter follower transistor to operate in a non-conductive state to isolate the charging node from the input during a hold mode. The cascode switch may include a MOS-HBT transistor combination operating in class AB mode.

Abstract: Described herein are embodiments of a diffractive optical element (23) such as a grism. In one embodiment, the diffractive optical element (23) includes an input surface (31) configured to receive an input optical signal (29), a diffractive surface (33) adapted to spatially disperse the input optical beam (29) into a dispersed signal and an output surface (35) configured to output the dispersed signal from the diffractive optical element. The input surface (31) and the diffractive surface (33) are non-parallel and the diffractive surface (33) is formed in situ by a photolithographic technique.

Abstract: A transmitter can include: at least one primary laser emitter configured to emit primary laser light; at least one primary monitor photodiode optically coupled with the at least one primary laser emitter; and at least one spare laser emitter configured to emit spare laser light. Each spare laser emitter can be adjacent with a corresponding primary laser emitter such that a first primary laser emitter and a first spare laser emitter pair are directed through an optical system and out a common optical fiber.

Abstract: Described herein is a diffraction grating (1) for use in an optical system. The diffraction grating includes a substrate (2) and an array of elongate diffracting elements (3) arranged in a grating profile across the substrate. The grating profile imparts a predefined phase change to optical beams to at least partially correct the beams for optical aberrations present in the optical system.

Abstract: A loss of signal (LOS) detector may include a comparator including a first input, a second input and an output indicating a LOS status. The LOS detector further includes circuitry to compare a first signal on the first input generated by differential input signals and a threshold signal common mode with a second signal on the second input generated by differential threshold signals at a first level and an input signal common mode. The circuit further configured to generate a LOS indicator on the output based on the compare.

Abstract: An optoelectronic module is provide and includes an electronic unit, an optical unit, and an interconnect structure. The electronic unit is capable of outputting and/or receiving electric signals, while the optical unit is capable of converting the electric signals into optical signals. The interconnect structure connects the electronic unit and the optical unit, and includes an electrically conducting substrate and a pair of transmission leads connecting electronic unit and the optical unit. The pair of transmission leads includes a signal lead and a ground lead having lower impedance than the signal lead.

Abstract: In an example, a system includes a grating coupled laser and a photonic integrated circuit. The grating coupled laser includes a first waveguide and a transmit grating coupler optically coupled to the first waveguide. The photonic integrated circuit includes a second waveguide and a receive grating coupler optically coupled to the second waveguide. The second grating coupler may include a negative angle grating coupler.

Abstract: A system may include a first module at a far end, and an optical fiber coupled to the first module. The system may also include a second module at a near end that is configured to generate and transmit instructions to the first module to control operation of the first module.