Tunable filters based on an SOI nano-wire waveguide micro ring resonator

Micro ring resonator（MRR） filters based on a silicon on insulator（SOI） nanowire waveguide are fabricated by electron beam photolithography（EBL） and inductive coupled plasma（ICP） etching technology.The cross-section size of the strip waveguides is 450×220 nm2,and the bending radius of the micro ring is around 5μm.The test results from the tunable filter based on a single ring show that the free spectral range（FSR） is 16.8 nm and the extinction ratio（ER） around the wavelength 1550 nm is 18.1 dB.After thermal tuning,the filter＇s tuning bandwidth reaches 4.8 nm with a tuning efficiency of 0.12 nm/℃Meanwhile,we fabricated and studied multi-channel filters based on a single ring and a double ring.After measurement,we drew the following conclusions： during the signal transmission of multi-channel filters,crosstalk exists mainly among different transmission channels and are fairly distinct when there are signals input to add ports.

Fabrication of a novel silica PLC hybrid integrated triplexer

A new-style silica planar lightwave circuit（PLC） hybrid integrated triplexer,which can demultiplex 1490- nm download data and 1550-nm download analog signals,as well as transmit 1310-nm upload data,is presented.It combines SiO2 arrayed waveguide gratings（AWGs） with integrated photodetectors（PDs） and a high performance laser diode（LD）.The SiO2 AWGs realize the three-wavelength coarse wavelength-division multiplexing（CWDM）.The crosstalk is less than - 40 dB between the 1490- and 1550-nm channels, and less than - 45 dB between 1310- and 1490- or 1550-nm channels.For the static performances of the integrated triplexer,its upload output power is 0.4 mW,and the download output photo-generated current is 76μA.In the small-signal measurement,the upstream -3-dB bandwidth of the triplexer is 4 GHz,while the downstream -3-dB bandwidths of both the analog and digital sections reach 1.9 GHz.

Luminescence enhancement from Si-based materials by introducing a photonic crystal double-heterostructure slot waveguide microcavity

We demonstrate a novel SOI-based photonic crystal（PC） double-heterostructure slot waveguide microcavity constructed by cascading three PC slot waveguides with different slot widths,and simulate the luminescence enhancement of sol-gel Er-doped SiO2 filled in the microcavity by finite-difference time-domain（FDTD） method.The calculated results indicate that a unique sharp resonant peak dominates in the spectrum at the expected telecommunication wavelength of 1.5509 mm,with very high normalized peak intensity of ~108.The electromagnetic field of the resonant mode exhibits the strongest in the microcavity,and decays rapidly to zero along both sides,which means that the resonant mode field is well confined in the microcavity.The simulation results fully verify the enhancement of luminescence by PC double-heterostructure slot waveguide microcavity theoretically,which is a promising way to realize the high-efficiency luminescence of Si-based materials.

Quadric surface projection model for fish-eye cameras

The curved surface projection model in fisheye image correction algorithm is presented. To analyze the causes of distortion in existing models, we establish an ideal surface projection model and compare its surface with the surfaces of existing models. Subsequently, feature points are obtained on the ideal surface according to the relationship of coordinates of fish-eye image points and their ideal three-dimentional （3D） points. Finally, the least square method is used to obtain a quadrie surface and presents a quadric surface projection model. The experiment shows that the corrected image of the new model is more similar to the actual scene than the corrected images of previous models.