Tunable wavelength filters using polymer long-period waveguide gratings based on metal-cladding directly defined technique

In this work, long-period waveguide grating-based tunable wavelength filters using organic–inorganic grafting poly（methyl methacrylate）（PMMA） materials are designed and fabricated by metal-cladding directly defined technique.The thermal stabilities and optical properties of the organic–inorganic grafting PMMA core materials are analyzed. Structures and performance parameters of the waveguide gratings and self-electrode heaters are designed and simulated. The contrast of the filter is about 15 d B and the resonant wavelength can be tuned by different electric powers applied to the metal-cladding self-electrode heaters. The temperature sensitivity is 3.5 nm/℃ and the switching time is about 1 ms. The technique is very suitable for realizing the optoelectronic integrated wavelength-division-multiplexing systems.

FLUORINATED PHTHALAZINONE-CONTAINING COPOLYIMIDES FOR PASSIVE OPTICAL WAVEGUIDES

A series of fluorinated copolyimides containing phthalazinone moieties were prepared from 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride(6FDA),3,3'4,4'-benzophenone-tetracarboxylic dianhydride(BPDA)and2-(4-aminophenyl)-4-[4-(4-aminophenoxyl)phenyl]-2,3-phthalazin-1-one(DHPZ-2NH_2)for making polymeric opticalwaveguides.The resulting copolymers containing 0-50 mo1% BPDA/DHPZ-2NH_2 show good solubility and are soluble insome organic polar aprotic solvents.The copolyimides also present excellent thermal stability.These polymers possess highglass transition temperature higher than 603 K and high decomposition temperature above 742 K determined by differentialscanning calorimetry and thennogravimetric analysis,respectively,under a nitrogen atmosphere.Their refractive indicescould be controlled by varying the ratio of 6FDA and BPDA in the copolymer from 0.5 to 1.0,and the in-plane refractiveindices(n_(TE))range from 1.6366 to 1.6668 and the out-of-plane refractive indices(n_(TM))from 1.6024 to 1.6280 at 632.8 nm.The polymers birefringence(0.0342-0.0388)is almost independent of the 6FDA content of copolymer,which indicated thatthe phthalazinone-containing copolyimides could be suitable to fabricate optical waveguides possessing a low polarizationdependent loss(PDL).

Vertically Integrated Thermo-Optic Waveguide Switch Using Optical Polymers

We propose and fabricate a vertically integrated thermo-optic waveguide switch. It controls the optical path between two vertically stacked waveguides using the thermo-optic effect of optical polymer. The measured crosstalk is less than -10 dB.

A strategy for preparing broadband polymer based optical waveguide amplifiers:doping low crystal field symmetric nanocrystals in polymer matrix as gain media

Optical waveguide amplifiers are essential devices in integrated optical systems,with their gain bandwidths directly influencing the operating wavelengths of optical circuits.Previous Er^(3+)-doped polymer optical waveguide amplifiers have been limited to amplifying signals within the C-band.To achieve broadband polymer optical waveguide amplification,we propose the use of nanocrystals with low crystal field symmetry to extend the working bandwidth.Our approach utilizes LiYF_(4):Yb,Er nanoparticles embedded in poly(methyl methacrylate)as the gain medium,enabling signal amplification from most of the S-band to the whole(C+L)band.The low crystal field symmetry of the LiYF_(4)host significantly splits the^(4)I_(13/2)and^(4)I_(15/2)levels of Er^(3+)ions owing to the crystal field effect,facilitating broadband down-conversion luminescence under 980-nm excitation.Furthermore,a fluorescence kinetic analysis confirms that the broadband luminescence of Er^(3+)arises from significant energy-level splitting caused by the crystal field effect.Under 980-nm excitation,the amplifiers exhibited relative gains of approximately 12.6 dB at 1535 nm,7.4 dB at 1480 nm,and 3.7 dB at 1610 nm.The Er^(3+)-doped broadband polymer optical waveguide amplifier was successfully prepared.

Novel elastomeric spiropyran‑doped poly(dimethylsiloxane)optical waveguide for UV sensing

Novel poly(dimethylsiloxane)(PDMS)doped with two diferent spiropyran derivatives(SP)were investigated as potential candidates for the preparation of elastomeric waveguides with UV-dependent optical properties.First,free-standing flms were prepared and evaluated with respect to their photochromic response to UV irradiation.Kinetics,reversibility as well as photofatigue and refractive index of the SP-doped PDMS samples were assessed.Second,SP-doped PDMS waveguides were fabricated and tested as UV sensors by monitoring changes in the transmitted optical power of a visible laser(633 nm).UV sensing was successfully demonstrated by doping PDMS using one spiropyran derivative whose propagation loss was measured as 1.04 dB/cm at 633 nm,and sensitivity estimated at 115%change in transmitted optical power per unit change in UV dose.The decay and recovery time constants were measured at 42 and 107 s,respectively,with an average UV saturation dose of 0.4 J/cm2.The prepared waveguides exhibited a reversible and consistent response even under bending.The sensor parameters can be tailored by varying the waveguide length up to 21 cm,and are afected by white light and temperatures up to 70℃.This work is relevant to elastomeric optics,smart optical materials,and polymer optical waveguide sensors.