Abstract: The present invention provides a system, apparatus and method to maintain the polarization state of an optical signal propagating within a photonic integrated circuit, or from a first photonic integrated circuit to a second photonic integrated circuit. According to various embodiments of the invention, an optical circuit is provided which includes a waveguide having one or more bends or curved portions. The bends or curved portions of the waveguide are configured to maintain the polarization orientation of the optical signal as the optical signal propagates through the waveguide, such that the polarization orientation at inputs or outputs, or at various points along the waveguide is known. Embodiments of the present invention mitigate polarization crosstalk, which in turn provides for improved processing efficiency.

Abstract: The present invention provides a system, apparatus and method to maintain the polarization state of an optical signal propagating within a photonic integrated circuit, or from a first photonic integrated circuit to a second photonic integrated circuit. According to various embodiments of the invention, an optical circuit is provided which includes an optical coupler configured to accept a first optical signal on a first input and a second optical signal on a second input, the second optical signal having a polarization state. The optical coupler may combine the first and second optical signals into an optical output signal. A principle axis of a first end of an optical fiber is may be configured to align with the polarization state of the second optical signal, such that a polarization maintaining connection is established. The polarization state may be a TM polarization state, a TE polarization state, or another polarization state.

Abstract: The present invention provides for a semiconductor laser having a narrow linewidth and low power consumption for optical communication applications. According to various embodiments of the invention, a semiconductor laser is provided which includes a grating layer comprising a plurality of segmented gratings, each including a non-grating portion and a grating portion. The segmented gratings are configured to enhance a fundamental mode of the semiconductor laser while sufficiently suppressing modes other than the fundamental mode, providing a narrow linewidth for example. The segmented gratings are also configured to provide an effective length longer than an actual length of the semiconductor laser, leading to smaller device areas and corresponding lower power consumption. A photonic integrated circuit is also provided which includes a plurality of semiconductor lasers, consistent with the present invention, as well as additional optical elements, all provided on a single substrate.

Abstract: Consistent with the present disclosure, a current blocking layer is provided between output waveguides carrying light to be sensed by the photodiodes in a balanced photodetector, and the photodiodes themselves. Preferably, the photodiodes are provided above the waveguides and sense light through evanescently coupling with the waveguides. In addition, the current blocking layer may include alternating p and n-type conductivity layers, such that, between adjacent ones of such layers, a reverse biased pn-junction is formed. The pn-junctions, therefore, limit the amount of current flowing from one photodiode of the balanced detector to the other, thereby improving performance.

Abstract: The present invention provides a system, apparatus and method to provide for amplification at various points along one or more optical paths of a photonic integrated circuit. According to various embodiments of the invention, the photonic integrated circuit includes a plurality of optical devices having associated characteristics which may have lead to optical signal degradation. One or more optical amplifiers provided along one or more optical paths of the photonic integrated circuit compensate for such signal degradation, resulting in a highly configurable photonic integrated circuit. The various optical devices of the photonic integrated circuit may be provided on a single substrate.

Abstract: Consistent with an aspect of the present disclosure, a package is provided that has a carrier and first and second substrates provided on the carrier. Conductive traces are provided on the first substrate (upper traces) and below it (lower traces) to provide two levels of electrical connectivity to a photonic integrated circuit (PIC) provided on the second substrate. As a result, an increased number of connections can be made to the PIC in a relatively small package, while maintaining adequate spacing and line widths for each trace. In addition, the lower traces are connected to bonding pads on the surface of the first substrate and are thus provided in the same plane as the upper traces. Testing of and access to both upper and lower traces is thus simplified.

Abstract: Consistent with the present disclosure, the number of passive waveguides in a PIC are reduced by directly connecting active components to one another. Accordingly, optical signals propagating in the PIC may experience less loss, and, thus, improved performance may be achieved. In addition, active components may be bent or curved in order to obtain a more compact layout with greater device density. Reduced manufacturing costs can therefore be realized.

Abstract: According to this disclosure, embodiments of the present invention include photonic integrated circuits having active and passive geometric regions geometrically arranged to provide for more compact integrated photonic integrated circuits which, in turn, leads to higher chip yields and lower fabrication costs.

Abstract: A dual output laser source provided on a substrate outputs light from a first and second output. A portion of the light generated by the laser is supplied to a first modulator via the first output. A second portion of the light generated by the laser is supplied to a second modulator via the second output. The first modulator is provided on the substrate and generates a first modulated signal. The second modulator is also provided on the substrate and generates a second modulated signal. Each output of the laser is used to provide continuous wave light sources to components on photonic integrated circuit.

Abstract: A high capacity optical transmitter implemented on a photonic integrated circuit chip comprises a single light source which supplies a continuous wave having a particular wavelength to a plurality of modulators to form modulated optical information signals. A phase shifter is coupled to at least one of the modulators and is used to shift the phase of the corresponding modulated optical information signal associated with a particular modulator. A polarization beam combiner receives each of the modulated optical information signals from the modulators and the modulated optical information signal from the phase shifter and combines each of these signals to form a polarization multiplexed differential quadrature phase-shift keying signal. The light source, the plurality of modulators, the phase shifter and the polarization beam combiner are all integrated on the chip.

Abstract: Consistent with the present disclosure, various optical components are preferably arranged on the surface of a semiconductor substrate such that light propagates in certain components at a direction that is perpendicular to a direction of propagation in other components in order to improve performance and component density.

Abstract: System, devices and methods are described that provide an integrated optical decombiner or optical combiner having both unamplified paths and amplified paths on which power monitoring and control may be located. A preferred multiplexing/demultiplexing optical path through the combiner/decombiner and a corresponding waveguide output/input is identified and optically coupled to a piece of fiber. Temperature control may be provided to tune an arrayed waveguide grating within the combiner/decombiner and minimize wavelength drift therein. Integrated power monitoring may be employed on one or more of the amplified waveguide paths to ensure that a preferred power level or range is maintained on an optical signal.

Abstract: An electrically pumped optical device includes a semiconductor active region and a backward diode. Both of these structures are located in the current path of the optical device, which is oriented primarily vertically. The active region has a finite extent along at least one lateral dimension. The overall structure improves the electrical performance of the device.

Abstract: An optical amplifier with damped relaxation oscillation. A large distance between mirrors in a VLSOA increases damping for the relaxation oscillation. Alternatively, a feedback loop damps out relaxation oscillations.

Abstract: Semiconductor devices and methods are disclosed in which the amount of p-type material can be minimized, with attendant advantages in electrical, thermal, and optical performance, and in fabrication. A form of the disclosure is directed to a generally planar semiconductor device wherein a layer of p-type semiconductor material is disposed over a layer of n-type semiconductor material, and an electric potential is coupled between the p-type layer and the n-type layer, and wherein current in the device that is lateral to the plane of the layers is coupled into the p-type layer. A tunnel junction is adjacent the p-type layer for converting the lateral current into hole current. In an embodiment of this form of the disclosure, the tunnel junction is an n+/p+ junction oriented with the p+ portion thereof adjacent the p-type layer. The lateral current can be electron current in the n+ layer and/or electron current in a further layer of n-type material disposed over the tunnel junction.