Abstract: The present disclosure provides a system, apparatus and method to for providing highly manufacturable compact optical structures in optical circuits, increasing overall yield and lowering manufacturing costs. According to one aspect, an optical circuit is provided which includes an multimode interference element and first and second waveguides. The first waveguide may be provided adjacent a first side of the optical device and extending along at least the length of the multimode interference element, while the second waveguide may be provided adjacent a second side of the multimode interference element and extending along at least the length of the optical device. Each of the first and second waveguide have first and second ends which may be configured to dissipate propagating light in the first and second waveguides.

Abstract: Consistent with the present disclosure, MZ drive signal electrodes may be provided relatively close to and parallel to one another, such that the underlying waveguide arms may also be provided close to and parallel to one another. As a result, common mode performance of an MZ modulator may be obtained. In one example, an electrode wiring configuration consistent with the present disclosure may permit a waveguide arm separation of 40 microns or less.

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 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: A device may include a number of optical waveguides, each of which being spaced from one another. The optical waveguides may each include at least one curved section and widths of the curved sections of the optical waveguides may be selected to reduce polarization conversion of light traversing the birefringent optical waveguides.

Abstract: Consistent with the present disclosure, an optical receiver is paired with an optical transmitter in a transceiver card or module, for example. During normal operation, the optical transmitter supplies optical signals for downstream transmission on a first optical communication path, and the optical receiver receives additional optical signals from a second optical communication path. During a transmitter monitoring mode (or “loopback”), however, when monitoring of transmitter parameters is desired, an optical switch directs the output or portion thereof from the transmitter to the receiver. The receiver may then supply monitoring data or information to a control or processor circuit, which, in turn, may supply control signals to the transmitter. In response to such control signals, the performance of the transmitter may be optimized, for example, by reducing BER and/or OSNR to a desired level.

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: Consistent with the present disclosure, both arms of an MZ interferometer are “double-folded” and are bent in at least two locations to define first and second acute inner angles. Accordingly, the arms of the MZ interferometer may have substantially the same length, and, further, the MZ interferometer has a more compact geometry. In one example, the arms parallel each other and have a serpentine shape, and, in a further embodiment, the arms parallel one another and have a Z-shape. Accordingly, since the temperature of a PIC upon which the MZ interferometer is provided does not vary significantly over such short distances, the temperatures of both arms is substantially the same.

Abstract: Consistent with the present disclosure, MZ drive signal electrodes may be provided relatively close to and parallel to one another, such that the underlying waveguide arms may also be provided close to and parallel to one another. As a result, common mode performance of an MZ modulator may be obtained. In one example, an electrode wiring configuration consistent with the present disclosure may permit a waveguide arm separation of 40 microns or less.

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: 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 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: 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: 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: 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: 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: Consistent with the present disclosure, an optical receiver is paired with an optical transmitter in a transceiver card or module, for example. During normal operation, the optical transmitter supplies optical signals for downstream transmission on a first optical communication path, and the optical receiver receives additional optical signals from a second optical communication path. During a transmitter monitoring mode (or “loopback”), however, when monitoring of transmitter parameters is desired, an optical switch directs the output or portion thereof from the transmitter to the receiver. The receiver may then supply monitoring data or information to a control or processor circuit, which, in turn, may supply control signals to the transmitter. In response to such control signals, the performance of the transmitter may be optimized, for example, by reducing BER and/or OSNR to a desired level.

Abstract: Consistent with the present disclosure, an optical receiver is paired with an optical transmitter in a transceiver card or module, for example. During normal operation, the optical transmitter supplies optical signals for downstream transmission on a first optical communication path, and the optical receiver receives additional optical signals from a second optical communication path. During a transmitter monitoring mode (or “loopback”), however, when monitoring of transmitter parameters is desired, an optical switch directs the output or portion thereof from the transmitter to the receiver. The receiver may then supply monitoring data or information to a control or processor circuit, which, in turn, may supply control signals to the transmitter. In response to such control signals, the performance of the transmitter may be optimized, for example, by reducing BER and/or OSNR to a desired level.

Abstract: The present disclosure provides a system, apparatus and method to for providing highly manufacturable compact optical structures in optical circuits, increasing overall yield and lowering manufacturing costs. According to one aspect, an optical circuit is provided which includes an multimode interference element and first and second waveguides. The first waveguide may be provided adjacent a first side of the optical device and extending along at least the length of the multimode interference element, while the second waveguide may be provided adjacent a second side of the multimode interference element and extending along at least the length of the optical device. Each of the first and second waveguide have first and second ends which may be configured to dissipate propagating light in the first and second waveguides.

Abstract: Consistent with the present disclosure, an arrayed waveguide grating (AWG) is provided that includes first inputs and second inputs. Each of the first inputs receives a corresponding one of a plurality of first optical signals, each of which has a corresponding one of a plurality of wavelengths. Second inputs are also provided, such that each second input is preferably provided between two adjacent first inputs. Each of the second inputs receives a corresponding one of a plurality of second optical signals, and each of the second plurality of optical signals has a corresponding one of those wavelengths. Each of the first plurality of optical signals, however, has a first polarization and each of the second plurality of optical signals has a second polarization different than the first polarization.