Abstract:
A clock data recovery circuit (CDR) extracts bit data values from a serial bit stream without reference to a transmitter clock. A controllable oscillator produces a regenerated clock signal controlled to match the frequency and phase of transitions between bits and the serial data is sampled at an optimal phase. A phase detector generates early-or-late indication bits for clock versus data transition times, which are accumulated and applied to a second order feedback control with two distinct feedback paths for frequency and phase, combined for correcting the controllable oscillator, selecting a sub-phase and/or determining an optimal phase at which the bit stream data values are sampled. The second order filter is operated at distinct rates such that the phase correction has a latency as short as one clock cycle and the frequency correction latency occurs over plural cycles.
Abstract:
Apparatus and circuits with dual threshold voltage transistors and methods of fabricating the same are disclosed. In one example, a semiconductor structure is disclosed. The semiconductor structure includes: a substrate; a first layer comprising a first III-V semiconductor material formed over the substrate; a first transistor formed over the first layer, and a second transistor formed over the first layer. The first transistor comprises a first gate structure comprising a first material, a first source region and a first drain region. The second transistor comprises a second gate structure comprising a second material, a second source region and a second drain region. The first material is different from the second material.
Abstract:
An optical system with different optical coupling device configurations and a method of fabricating the same are disclosed. An optical system includes a substrate, a waveguide disposed on the substrate, an optical fiber optically coupled to the waveguide, and an optical coupling device disposed between the optical fiber and the waveguide. The optical coupling device configured to optically couple the optical fiber to the waveguide. The optical coupling device includes a dielectric layer disposed on the substrate, a semiconductor tapered structure disposed in a first horizontal plane within the dielectric layer, and a multi-tip dielectric structure disposed in a second horizontal plane within the dielectric layer. The first and second horizontal planes are different from each other.
Abstract:
Disclosed are edge couplers having a high coupling efficiency and low polarization dependent loss, and methods of making the edge couplers. In one embodiment, a semiconductor device for optical coupling is disclosed. The semiconductor device includes: a substrate; an optical waveguide over the substrate; and a plurality of layers over the optical waveguide. The plurality of layers includes a plurality of coupling pillars disposed at an edge of the semiconductor device. The plurality of coupling pillars form an edge coupler configured for optically coupling the optical waveguide to an optical fiber placed at the edge of the semiconductor device.
Abstract:
In some embodiments, the present disclosure relates to an integrated chip that includes an insulator layer arranged over a substrate. Further, an upper routing structure is arranged over the insulator layer and is made of a semiconductor material. A lower optical routing structure is arranged below the substrate and is embedded in a lower dielectric structure. The integrated chip further includes an anti-reflective layer that is arranged below the substrate and directly contacts the substrate.
Abstract:
A photonic structure is provided. The photonic structure includes a semiconductor substrate, a buried oxide layer over the semiconductor substrate, an optical coupling region over the buried oxide layer, and an oxide structure embedded in the semiconductor substrate. The optical coupling region is tapered toward a terminus of the optical coupling region located at an edge of the semiconductor substrate. The optical coupling region overlaps the oxide structure in a plan view.
Abstract:
Apparatus and circuits with dual polarization transistors and methods of fabricating the same are disclosed. In one example, a semiconductor structure is disclosed. The semiconductor structure includes: a substrate; an active layer that is formed over the substrate and comprises a first active portion having a first thickness and a second active portion having a second thickness; a first transistor comprising a first source region, a first drain region, and a first gate structure formed over the first active portion and between the first source region and the first drain region; and a second transistor comprising a second source region, a second drain region, and a second gate structure formed over the second active portion and between the second source region and the second drain region, wherein the first thickness is different from the second thickness.
Abstract:
Some embodiments relate to a phase interpolator. The phase interpolator includes a control block to provide a plurality of phase interpolation control signals which are collectively indicative of a phase difference between a first clock and a second clock. The phase interpolation control signals define different phase step sizes by which the first clock is to be phase shifted to limit the phase difference. A plurality of Gilbert cells provide a plurality of current levels, respectively, based on the plurality of phase interpolation control signals. A plurality of current control elements adjust the plurality of current levels from the plurality of Gilbert cells. The plurality of current levels are adjusted by different amounts for the different phase step sizes.
Abstract:
A circuit includes a capacitive-load voltage controlled oscillator having an input configured to receive a first input signal and an output configured to output an oscillating output signal. A calibration circuit is coupled to the voltage controlled oscillator and is configured to output one or more control signals to the capacitive-load voltage controlled oscillator for adjusting a frequency of the oscillating output signal. The calibration circuit is configured to output the one or more control signals in response to a comparison of an input voltage to at least one reference voltage.
Abstract:
Apparatus and circuits including transistors with different polarizations and methods of fabricating the same are disclosed. In one example, a semiconductor structure is disclosed. The semiconductor structure includes: a substrate; an active layer that is formed over the substrate and comprises a first active portion and a second active portion; a first transistor comprising a first source region, a first drain region, and a first gate structure formed over the first active portion and between the first source region and the first drain region; and a second transistor comprising a second source region, a second drain region, and a second gate structure formed over the second active portion and between the second source region and the second drain region, wherein the first active portion has a material composition different from that of the second active portion.