Extinction ratio

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

10 Gb/s Reconfigurable Optical Logic Gate Using a Single Hybrid-Integrated SOA-MZI

Abstract: A novel reconfigurable Boolean device based on a single Mach-Zehnder interferometer with semiconductor optical amplifiers is demonstrated at 10 Gb/s using intensity return-to-zero modulated signals. The experimental results show that the device can be dynamically reconfigured to operate as a logic XOR, AND, OR, and NOT gate using optical switches. By properly adjusting the input powers, an extinction ratio higher than 10 dB may be obtained. The potential of integration of this architecture makes it an interesting approach in photonic computing and optical signal processing.

Ultracompact and Broadband Silicon-Based Polarization Beam Splitter Using an Asymmetrical Directional Coupler

Abstract: An ultracompact and broadband polarization beam splitter (PBS) is proposed by using an asymmetrical directional coupler composed of a hybrid plasmonic waveguide (HPW) and a regular silicon wire (RSW). By properly choosing the structural parameters, transverse-magnetic (TM) mode is cutoff for the RSW and phase-matching condition is only satisfied for transverse-electric (TE) mode. As a result, the input TM-mode in HPW directly passes through, while the input TE-mode in the same HPW is coupled into the RSW. Consequently, the two polarized modes can be effectively separated. Moreover, the present PBS shows fabrication-friendly design and its length can be significantly reduced, since the gap between the HPW and RSW can be shortened to zero. From the results, a ~2.6- $\mu \text{m}$ -long PBS with a coupling length of $0.1~\mu \text{m}$ is achieved and its bandwidth is ~120 nm with a polarization extinction ratio over 14 dB, and an insertion loss below 1 dB for both polarizations. In addition, fabrication tolerances to the key structural parameters are analyzed in detail and field evolution through the designed PBS is also presented.

Integrated polarization beam splitter with relaxed fabrication tolerances.

Abstract: Polarization handling is a key requirement for the next generation of photonic integrated circuits (PICs). Integrated polarization beam splitters (PBS) are central elements for polarization management, but their use in PICs is hindered by poor fabrication tolerances. In this work we present a fully passive, highly fabrication tolerant polarization beam splitter, based on an asymmetrical Mach-Zehnder interferometer (MZI) with a Si/SiO(2) Periodic Layer Structure (PLS) on top of one of its arms. By engineering the birefringence of the PLS we are able to design the MZI arms so that sensitivities to the most critical fabrication errors are greatly reduced. Our PBS design tolerates waveguide width variations of 400nm maintaining a polarization extinction ratio better than 13dB in the complete C-Band.

Phase-Tunable Low-Loss, $S$ -, $C$ -, and $L$ -Band DPSK and DQPSK Demodulator

Abstract: Differential phase-shift keying (DPSK) and differential quadrature phase-shift keying (DQPSK) are touted as performers and reliable advanced modulation formats for next-generation optical transmission systems. One key device enabling such systems is the delay interferometer, converting the signal phase information into intensity modulation to be detected by the photodiodes. We developed an all-fiber delay-line interferometer for DPSK and DQPSK demodulation in the S-, C-, and L-band with low insertion loss, low-birefringence, and greater than 30 dB of extinction ratio over 100 nm and 20 dB from 1460 to 1640 nm in a single device. The device also features insensitivity to mechanical vibration, very low port imbalance (0.1 dB), and very low time delay between all outputs (0.1 ps). The device is highly reliable with a demonstrated failure-in-time rate of less than 100.

Analysis of integrated-optics near 3 dB coupler and Mach-Zehnder interferometric modulator using four-port scattering matrix

Abstract: The scattering matrix formalism for a lossless four-port device is used to describe the interferometric performance of the integrated-optics near 3 dB coupler and, consequently, the Mach-Zehnder interferometric modulator as a function of coupler and/or power imbalance. For the case of a coupler consisting of three single-mode dielectric guides forming a Y junction, a fourth port is incorporated which takes all the power radiated out of the guided-wave system in the vicinity of the junction. The interferometric properties of the coupler are shown to be relatively insensitive to fabrication and/or design errors of a magnitude which would make the use of this junction in the reverse direction as a 3 dB divider very marginal. A coupler with an extinction ratio as an interferometer better than -26 dB corresponds to a power divider which couples 22 percent more power into one arm than the other. It is also shown that the near 3 dB coupler used as the output of an interferometric modulator is similarly insensitive to the inequality of the powers in the two arms.