Optimization of efficiency-loss figure of merit in carrier-depletion silicon Mach-Zehnder optical modulator.

In this paper we study the optimization of interleaved Mach-Zehnder silicon carrier depletion electro-optic modulator. Following the simulation results we demonstrate a phase shifter with the lowest figure of merit (modulation efficiency multiplied by the loss per unit length) 6.7 V-dB. This result was achieved by reducing the junction width to 200 nm along the phase-shifter and optimizing the doping levels of the PN junction for operation in nearly fully depleted mode. The demonstrated low FOM is the result of both low V(π)L of ~0.78 Vcm (at reverse bias of 1V), and low free carrier loss (~6.6 dB/cm for zero bias). Our simulation results indicate that additional improvement in performance may be achieved by further reducing the junction width followed by increasing the doping levels.

Silicon-metal waveguide as a high efficiency Schottky detector for telecom wavelengths

We demonstrate an integrated on-chip compact and high efficiency Schottky detector for telecom wavelengths based on silicon metal waveguide. Detection is based on the internal photoemission process. Theory and experimental results are discussed. © 2012 OSA.

Silicon-metal waveguide as a high efficiency schottky detector for telecom wavelengths

We demonstrate an integrated on-chip compact and high efficiency Schottky detector for telecom wavelengths based on silicon metal waveguide. Detection is based on the internal photoemission process. Theory and experimental results are discussed. © 2012 Optical Society of America.

Switch mode constant current LED Driver with high efficiency, high precision and wide dimming ratio

A high efficiency hard switching constant current LED driver is presented with high overall efficiency, high current precision, high LED efficacy, flicker-free and wide constant current dimming ratio. The high stable lighting source provides the best solution for office light, reading light and LCD backlight. © 2013 IEEE.

Carrierless amplitude and phase modulation for low-cost,high-spectral-efficiency optical datacommunication links

Carrierless amplitude and phase modulation for next-generation datacommunication links is considered for the first time. Low-cost implementation of a high-spectral-efficiency 10 Gb/s channel is demonstrated as a route to links at 40 Gb/s and beyond. © 2010 Optical Society of America.

Gigabit/s modulation of twin-electrode high-brightness tapered laser with high modulation efficiency

Simultaneous high modulation speed and high modulation efficiency operation of a two-electrode tapered laser is reported. 1Gb/s direct data modulation is achieved with 68mA applied current swing for a 0.95W output optical modulation amplitude. © 2009 Optical Society of America.

APSK coded modulation schemes for nonlinear satellite channels with high power and spectral efficiency

A new class of 16-ary Amplitude Phase Shift Keying (APSK) coded modulations deemed double-ring PSK modulations best suited for (satellite) nonlinear channels is proposed. Constellation parameters optimization has been based on geometric and information-theoretic considerations. Furthermore, pre- and post-compensation techniques to reduce the nonlinearity impact have been examined. Digital timing clock and carrier phase have been derived and analyzed for a Turbo coded version of the same new modulation scheme. Finally, the performance of state-of the art Turbo coded modulation for this new 16-ary digital modulation has been investigated and compared to the known TCM schemes. It is shown that for the same coding scheme, double-ring APSK modulation outperforms classical 16-QAM and 16-PSK over a typical satellite nonlinear channel due to its intrinsic robustness against the High Power Amplifier (HPA) nonlinear characteristics. The new modulation is shown to be power- and spectrally-efficient, with interesting applications to satellite communications. © 2002 by the American Institute of Aeronautics and Astronautics, Inc.