Extinction ratio

About: Extinction ratio is a research topic. Over the lifetime, 8541 publications have been published within this topic receiving 111908 citations.

Low-voltage, high-extinction-ratio, Mach-Zehnder silicon optical modulator for CMOS-compatible integration

Abstract: We demonstrate a carrier-depletion Mach-Zehnder silicon optical modulator, which is compatible with CMOS fabrication process and works well at a low driving voltage. This is achieved by the optimization of the coplanar waveguide electrode to reduce the electrical signal transmission loss. At the same time, the velocity and impedance matching are both considered. The 12.5 Gbit/s data transmission experiment of the fabricated device with a 2-mm-long phase shifter is performed. The driving voltages with the swing amplitudes of 1 V and 2 V and the reverse bias voltages of 0.5 V and 0.8 V are applied to the device, respectively. The corresponding extinction ratios are 7.67 and 12.79 dB.

Stacked thermo-optic switch, switch matrix and add-drop multiplexer having the stacked thermo-optic switch

Abstract: Cores of an optical waveguide forming a Y-branch structured thermo-optic switch are stacked in a direction perpendicular to a substrate, and a heater is disposed on a clad right above an area where the cores overlap, thereby utilizing a large temperature gradient by the heater in the direction perpendicular to the substrate. The resulting stacked thermo-optic switch is low in power consumption and signal loss and high in extinction ratio.

Effects of crosstalk and timing jitter on all-optical time-division demultiplexing using a nonlinear fiber Sagnac interferometer switch

Abstract: All-optical time-division demultiplexing using a nonlinear fiber Sagnac interferometer switch (NSIS) is studied with respect to the two main causes that degrade the bit-error-rate (BER) performance: crosstalk and timing jitter. It is shown that unwanted cross-phase-modulation in the reference signal which counter-propagates to the control pulse, as well as the poor extinction of the switch itself, seriously degrades the extinction ratio of the switch, thus increasing the crosstalk from other channels. Numerical calculations clarify the effect of the switching window width, window shape, and the multiplexed channel number on the power penalty in terms of BER performance. Timing jitter between the signal and control pulses is investigated as another degradation factor that causes an error floor in BER performance. It is found that the minimum BER is obtained when the window width is set to the time slot width and the rms value of the jitter must be less than 1/14.1 times the time slot width to ensure that BER >

Broadband Silicon-On-Insulator directional couplers using a combination of straight and curved waveguide sections

Abstract: Broadband Silicon-On-Insulator (SOI) directional couplers are designed based on a combination of curved and straight coupled waveguide sections. A design methodology based on the transfer matrix method (TMM) is used to determine the required coupler section lengths, radii, and waveguide cross-sections. A 50/50 power splitter with a measured bandwidth of 88 nm is designed and fabricated, with a device footprint of 20 μm × 3 μm. In addition, a balanced Mach-Zehnder interferometer is fabricated showing an extinction ratio of >16 dB over 100 nm of bandwidth.

Fast electro‐optic waveguide deflector modulator

Abstract: We describe a high‐speed deflector‐modulator based on an electro‐optically induced thick phase grating in optical waveguides of single‐crystal epitaxial ZnO film on Al2O3 substrates. 40% of the beam is diffracted into first order with response times of 3 nsec. The extinction ratio in the deflected beam is greater than 95%. We predict 80% diffraction, response times of < 1 nsec, and power requirements of approximately 1 mW/MHz for an optimized geometry.