Extinction ratio

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

Optical 4x4 hitless slicon router for optical networks-on-chip (NoC).

Abstract: We demonstrate here a spatially non-blocking optical 4x4 router with a footprint of 0.07 mm(2) for use in future integrated photonic interconnection networks. The device is dynamically switched using thermo-optically tuned silicon microring resonators with a wavelength shift to power ratio of 0.25nm/mW. The design can route four optical inputs to four outputs with individual bandwidths of up to 38.5 GHz. All tested configurations successfully routed a single-wavelength laser and provided a maximum extinction ratio larger than 20 dB.

A low-cost WDM source with an ASE injected Fabry-Perot semiconductor laser

Abstract: We propose and demonstrate a novel wavelength-division-multiplexing (WDM) source employing an uncooled and unisolated Fabry-Perot semiconductor laser diode (F-P SLD). The output wavelength of F-P SLD is locked to the externally injected narrow-band amplified spontaneous emission (ASE). The measured side-mode suppression ratio of the wavelength-locked F-P SLD is larger than 29 dB, when the extinction ratio of the directly modulated light output is above 13 dB. We achieved error-free transmission of 155-Mb/s data over 120 km of nondispersion-shifted fiber. We also propose a cost-effective WDM passive optical network architecture based on the proposed light sources.

Fabrication of a 50 nm half-pitch wire grid polarizer using nanoimprint lithography

Abstract: We report the fabrication of a 50 nm half-pitch wire grid polarizer with high performance using nanoimprint lithography. The device is a form of aluminium gratings on a glass substrate whose size of 5.5 cm × 5.5 cm is compatible with a microdisplay panel. A stamp with a pitch of 100 nm was fabricated on a silicon substrate using laser interference lithography and sidewall patterning. The imprint and the aluminium etching processes are optimized to realize uniform aluminium gratings with aspect ratio of 4. The polarization extinction ratio of the fabricated device is over 2000, with transmission of 85% at a wavelength of 450 nm, which is the highest value ever reported. This work demonstrates that nanoimprint lithography is a unique cost-effective solution for nanopatterning requirements in consumer electronics components.

Non-reciprocal phase shift induced by an effective magnetic flux for light

Abstract: Photons are neutral particles that do not interact directly with a magnetic field. However, recent theoretical work has shown that an effective magnetic field for photons can exist if the phase of light changes with its direction of propagation. This direction-dependent phase indicates the presence of an effective magnetic field, as shown experimentally for electrons in the Aharonov–Bohm experiment. Here, we replicate this experiment using photons. To create this effective magnetic field we construct an on-chip silicon-based Ramsey-type interferometer. This interferometer has been traditionally used to probe the phase of atomic states and here we apply it to probe the phase of photonic states. We experimentally observe an effective magnetic flux between 0 and 2π corresponding to a non-reciprocal 2π phase shift with an interferometer length of 8.35 mm and an interference-fringe extinction ratio of 2.4 dB. This non-reciprocal phase is comparable to those of common monolithically integrated magneto-optical materials.

Refractive Index Sensing With Mach–Zehnder Interferometer Based on Concatenating Two Single-Mode Fiber Tapers

Abstract: A novel refractive index (RI) sensor based on a fiber Mach-Zehnder interferometer was realized by concatenating two single-mode fiber tapers separated by a middle section. The proposed device had a minimum insertion loss of 3 dB and maximum interferometric extinction ratio over 20 dB. The resolution (0.171 nm) of the two-taper sensor to its surrounding RI change (0.01) was found to be comparable to that (0.252 nm) of similar structures made from an identical long-period gratings pair, and its ease of fabrication makes it a low-cost alternative to existing sensing applications.