O-band surface-grating-coupled Si wavelength demultiplexing filter using cascaded directional couplers with 30-nm passband linewidth, 6-dB insertion loss and 23.4-dB polarization extinction is demonstrated for 64-Gbit/s NRZ-OOK with WDM channel extinction enhanced from 8.9-dB@1330nm to 14.6-dB@1325 nm.
We successfully demonstrated the 4-channel Ge waveguide photodetectors with an MZI WDM as an O-band CWDM receiver to receive the 212-Gbps NRZ-OOK and 480-Gbps 16-QAM-DMT data streams without digital signal processing compensation in a 2-km SMF link for satisfying the IEEE 802.3bs and 802.3cu standards.
We design a waveguide crossing with composite subwavelength (SW) structures, i.e., bridged SW grating (BSWG) waveguide structures and diagonally periodic holes (DPHs), on a partial parabolic single layer crossing (PPSLC) to improve its transmission. The BSWG is located before/after the input/output regions of the PPSLC and the DPHs are in the crossing region of the PPSLC. This waveguide crossing occupies a footprint of 6.2 μm × 6.2 μm upon a silicon-on-insulator wafer with 220-nm silicon device layer on 2-μm buried oxide. We successfully gain simulated results of the transmission up to 98.72% (−0.056 dB) and the crosstalk as low as −65 dB at an input wavelength of 1.55 μm.
The scattering of surface plasmon polariton (SPP) waves can be manipulated by various plasmonic structures. The plasmonic structure composed of arranged subwavelength nanobumps on a gold thin film is the promising structure to manipulation SPP wave. By controlling the geometric shape of the structures, the height, position, and pattern of scattered light from SPP wave can be modulated as desired. A clear single focusing spot can be reconstructed at a specific altitude by a particular curved structure with appropriate curvature and adjacent interspacing of nanobumps. The designed light patterns reconstructed by the focusing spot from the arranged curved structures at a specific observation plane are clearly demonstrated.
Nanobump structures are fabricated on the gold thin film by femtosecond laser direct writing (fs-LDW) technique. The
height and diameter of the gold nanobump are about 30nm, and 400 nm, respectively. The scattering light of surface
plasmon wave radiated from a nanobump is observed using a total internal reflection microscopy. A quarter-circle
structure composed of nanobumps is designed and produced to manipulate scattering light into specific pattern: The
focusing and diverging of the quarter circular structure in three dimensional space are demonstrated. The polarization
properties of focusing spot are also examined.
Yttrium aluminium garnet (YAG) has been widely used as a solid-state laser host because of its superior optical, thermal,
mechanical properties, as well as its plurality in hosting active ions with a wide range of ionic radii. Drawing YAG into
single crystalline fiber has the potential to further scale up the attainable power level with high mode quality. The recent
advancement on the codrawing laser-heated pedestal growth (CDLHPG) technique can produce glass-clad YAG
crystalline fibers for laser applications. The drawing speed can reach 10 cm/min for mass production. The CDLHPG
technique has shown advantages on transition-metal ion doped YAG and short-fluorescent-lifetime ion doped YAG host.
Compared to silica fiber lasers, the crystalline core offers high emission cross section for transition metal ions because of
the unique local matrix. The challenges on the development of
glass-clad YAG fibers, including core crystallinity,
diameter uniformity, dopant segregation, residual strain, post-growth thermal treatment, and the thermal expansion
coefficient mismatch between the crystalline core and glass clad are discussed. Chromium, ytterbium, and neodymium
ions doped YAG fiber lasers have been successfully achieved with high efficiency and low threshold power. Power
scaling with a clad-pump/side-coupling scheme using single clad or double clad YAG fibers is also discussed.
A Fabry-Perot interference enhanced surface plasmon resonance (SPR) sensor was designed and analyzed
numerically. In this paper, a micro-fluidic channel with two parallel interfaces formed on the metal film of an angularinterrogated
SPR sensor was employed. The shift of the narrow reflection dips as a function of the refractive index
change of the fluid (angular sensitivity Sθ ) was very high. Meanwhile, the angular dip width δθFWHM was very narrow (<0.01°) and can be adjusted by changing the thickness of the resonant cavity. The corresponding intrinsic sensitivity IS = Sθ/δθFWHM higher than 105 RIU-1 around the resonant angle can be achieved.
In recent years, photovoltaic cells have attracted much attention and extensively been studied by many groups. The
amorphous silicon (a-Si) thin film solar cells have the advantages of lower cost, less material consumption and potential
for the building-integrated applications although the conversion efficiency is usually below 10%. In this paper, we show
an a-Si thin film solar cell with periodical nanorod structures for light trapping enhancement and an ultrathin silver film
as transparent electrode with a lower resistance for performance improvement. In such a design, the conversion
efficiency can be greatly improved. The periodicity and duty ratio of the nanorods were optimized to enhance the
diffraction of the light within 500-900 nm into guided modes in the a-Si thin film and thus the total optical absorption
can be enhanced. Furthermore, a 5-nm ultrathin metal film was used as a transparent electrode to replace the
conventional transparent conductive oxide while having a lower sheet resistance of 9.6 Ω/ and a transmittance from
90% to 70% within the spectral range from 300 nm to 900 nm. Our design was analyzed by using the full-wave finiteelement
method to calculate the optical absorption of the incident sunlight in the a-Si thin film. According to the
simulation results, the light absorption can be relatively enhanced by 69.6% and the total conversion efficiency can be
relatively improved by 41.6% compared to the conventional thin film a-Si solar cell without nanorod structures.
A polarization-independent racetrack type micro-ring resonator formed by silicon-on-insulator slot waveguides with a
phase compensation section included was investigated and proposed. By tuning the ratio of lengths of the slot waveguide
and the channel waveguide the cumulative phase difference between quasi-TE and quasi-TM modes can be well
eliminated which allows for a polarization independent operation over a wide spectral range. The finesses are 226 and
225 for the quasi-TE and quasi-TM modes respectively, with a free spectral range of 9 nm achieved as well as a compact
device size of 30 μm, while delivering a good polarization-independent performance with the resonance mode mismatch
less than 0.5 nm.
Surface plasmon resonance (SPR) sensors have been studied thoroughly for the past two decades. However, we found that the angular sensitivity in a prism-coupled SPR sensor can be as high as 500 deg/refractive index unit (RIU), which is two times higher than the sensitivity that has ever been achieved in previous studies. Such a high angular sensitivity can be fully achieved by simply choosing a proper low-index prism and a sufficiently large resonant angle for the light signal at an appropriate wavelength with an optimal metal film thickness. A feasible implementation of such an SPR sensor design concept was also proposed, and an even higher sensitivity of 600 deg/RIU can be achieved.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.