Gazillion Bits, Inc.

Haiqing Wei

Shih-Yuan Wang

Xin Xue

M Saif Islam

Miao Zhu

Zuhua Zhu

Aly F Elrefaie

A semiconductor optical amplifier (SOA) apparatus and related methods are described. The SOA comprises a signal waveguide for guiding an optical signal along a signal path, and further comprises one or more laser cavities having a gain medium lying outside the signal waveguide, the gain medium being sufficiently close to the signal waveguide such that, when the gain medium is pumped with an excitation current, the optical signal traveling down the signal waveguide is amplified by an evanescent coupling effect with the laser cavity. When the gain medium is sufficiently pumped to cause lasing action in the laser cavity, gain-clamped amplification of the optical signal is achieved. Additional features relating to segmented laser cavities, separate pumping of laser cavity segments, DFB/DBR gratings, current profiling to improve ASE noise performance, coupled-cavity lasers, avoidance of injection locking effects, manipulation of gain curve peaks, integration with a tunable vertical cavity coupler, integration with a photodetector, integration with an RZ signal modulator, and other described features may be used with the evanescent coupling case or with an SOA having a laser cavity gain medium that is coextensive with the gain medium of the signal waveguide.

Semiconductor optical amplifier using laser cavity energy to amplify signal and method of fabrication thereof

An optical return-to-zero (RZ) signal generator and related methods are described in which a phase modulator causes a phase change in an optical signal responsive to a transition in a driving signal, and in which an interferometer receives the optical signal from the phase modulator and generates an optical pulse responsive to that phase change. Preferably, the interferometer introduces a fixed, unmodulated time delay between its two signal paths, the fixed time delay being selected such that destructive interference occurs at an output of the interferometer when the phase of the optical signal received from the phase modulator remains constant. However, when a rising or falling edge of the driving signal causes phases changes in the optical signal, the destructive interference at the output of the interferometer is disturbed, and an optical pulse is generated. The driving signal is a differentially encoded version of an input information signal. Alternatively, the driving signal is proportional to the input information signal and the transmitted RZ-formatted optical signal is a differentially encoded version of that signal. Features for regulating the fixed time delay, features for frequency shift compensation, features for loss compensation/equalization, and integrated single-chip and multiple-chip embodiments are also described.

Generation of optical signals with return-to-zero format

An integrated optical cross-connect device and associated methods are described, the cross-connect device comprising a plurality M of input waveguides formed in a first material layer of an integrated circuit, a plurality N of output waveguides formed in a second material layer of the integrated circuit, and a plurality MN of micromechanically actuated bridge elements formed in at least one intermediate layer lying between the first and second material layers. Responsive to an electrical control signal, each bridge element establishes an index-guided, nonreflecting optical path between its associated input waveguide and its associated output waveguide. Preferably, the bridge element comprises an arcuate waveguide structure substantially surrounded by air or other nonsolid material, the arcuate waveguide structure being twistably connected to a remainder of the intermediate layer by a narrow neck portion. When electrostatically actuated, one end of the arcuate waveguide structure rises to meet the input waveguide while the other end lowers to meet the output waveguide. Associated fabrication methods and an expandable, modular cross-connect system based on the cross-connect device are also described.

Electrically controllable integrated optical cross-connect

An apparatus and related method for transmitting an optical signal through a nonlinear medium such that nonlinearities caused by the medium are eliminated from the transmitted optical signal is described. The optical signal is presumed to have a duty cycle, wherein the optical signal is &ldquo;on&rdquo; during an active portion of the duty cycle and &ldquo;off&rdquo; during an inactive portion, the active portion being of equal or lesser duration than the inactive portion. The optical signal plus a delayed and weighted version of itself are transmitted through the nonlinear medium without mutual interference. The transmitted signals are then re-synchronized, weighted, and subtracted such that nonlinearities induced by the medium are canceled, but such that a signal proportional to a delayed version of the original optical signal survives.

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Sunnyvale, CA, United States of America

Haiqing Wei