Ion-exchanged Glass Optical Waveguides Research Articles

Optical and electrochemical gas sensing applications of Cu Tetraphenylporphyrin thin films

A Cu tetraphenylporphyrin (CuTPP) gas sensor has been designed and fabricated for detection of volatile organic compounds (VOCs). The synthesized CuTPP was characterized by X-ray photoelectron spectroscopy (XPS) and nuclear magnetic resonance spectroscopy (1H NMR), then deposited onto a single mode potassium (K+) ion-exchanged glass optical waveguide (OWG) surface by spin coating and dip-coating of a CuTPP thin film on the surface of an alumina ceramic tube, where they acted as a sensing layer. The surface topography of the CuTPP thin film/K+-exchanged layer was investigated by atomic force microscopy (AFM) and scanning electron microscopy (SEM), where it showed a root-mean-square (RMS) roughness of about 3.4 nm with cross-section of nanoparticles exhibit rectangular pyramid morphology. CuTPP film sensors used to detect styrene gas as a typical example of VOCs. The experimental results showed that, at room temperature, CuTPP thin film/K+-exchanged OWG sensing device revealed higher response to styrene and xylene in the range of 10 ppb-1000 ppm; the response to CuTPP electro-chemical sensor response to styrene and xylene were 3.6 and 2.3, respectively.

The fabrication and gas sensing application of a fast-responding m-CP-PVP composite film/potassium ion-exchanged glass optical waveguide

A simply designed sensor was able to measure trimethylamine (TMA) gas down to a concentration of 0.1 ppb at room temperature, and its response and recovery times were 1.4 s and 5.6 s, respectively.

Fabrication of sucrose biosensor based on single mode planar optical waveguide using co-immobilized plant invertase and GOD

In present studies, the new optical sensing platform based on optical planar waveguide (OPWG) for sucrose estimation was reported. An evanescent-wave biosensor was designed by using novel agarose–guar gum (AG) biopolymer composite sol–gel with entrapped enzymes (acid invertase (INV) and glucose oxidase (GOD)). Partially purified watermelon invertase isolated from Citrullus vulgaris fruit (specific activity 832unitsmg−1) in combination with GOD was physically entrapped in AG sol–gel and cladded on the surface of optical planar waveguide. Na+–K+ ion-exchanged glass optical waveguides were prepared and employed for the fabrication of sucrose biosensor. By addressing the enzyme modified waveguide structure with, the optogeometric properties of adsorbed enzyme layer (12μm) at the sensor solid–liquid interface were studied. The OPWG sensor with short response time (110s) was characterized using the 0.2M acetate buffer, pH 5.5. The fabricated sucrose sensor showed concentration dependent linear response in the range 1×10−10 to 1×10−6M of sucrose. Lower limit of detection of this novel AG–INV–GOD cladded OPWG sensor was found to be 2.5×10−11M sucrose, which indicates that the developed biosensor has higher sensitivity towards sucrose as compared to earlier reported sensors using various transducer systems. Biochips when stored at room temperature, showed high stability for 81 days with 80% retention of original sensitivity. These sucrose sensing biochips showed good operational efficiency for 10 cycles. The proper confinement of acid invertase and glucose oxidase in hydrogel composite was confirmed by scanning electron microscopy (SEM) images. The constructed OPWG sensor is versatile, easy to fabricate and can be used for sucrose measurements with very high sensitivity.

Analyses of ion-exchanged glass optical waveguides by means of secondary ion mass spectroscopy: Condensation of impurity halide ions at the surface

We analyzed the chemical composition of K+-exchanged glass optical waveguides (OWGs) by secondary ion mass spectroscopy. Extensive condensation of impurity halide ions took place at the surface of the OWGs in the ion-exchanging and annealing processes. The condensation of Cl ions is likely a cause of the abnormal behavior observed for soda-lime glass OWGs; that is, a guided mode having appeared during the annealing did not disappear even after long annealing. Moreover, it was suggested that a space charge layer was formed at the OWG surfaces owing to the condensation of the halide ions.

Highly Sensitive and Low Loss Ion-Exchanged Glass Optical Waveguides Constructed by the Successive Doping of K+ and Ag+ Ions

Abstract A K+ ion-exchanged glass optical waveguide (OWG) was combined with an Ag+ ion-exchanged glass OWG on one substrate by tapered velocity coupling to obtain a low loss and highly sensitive ion-exchanged OWG system. The relative sensitivity of the Ag+-doped region was more than 1000 times per unit length (the reference here being spectroscopic measurements with normal incidence of monitoring light). The attenuation of the guided light was 3—5 dB cm−1 at the highly sensitive part. Stability against heat and against UV-irradiation were investigated also.

Ion-Exchanged Glass Optical Waveguide Systems for Surface Spectroscopy. Composite Structures for Realization of High Sensitivity and Low Loss

Abstract A K+-doped glass optical waveguide (OWG) and an Ag+-doped glass OWG were combined on one substrate using tapered velocity couplers to realize OWG systems for surface spectroscopy with high sensitivity and low loss. The high sensitivity part (Ag+-doped region) was more than 1000 times sensitive compared with optical measurements with normal incidence of monitoring light.

Fracture mechanics determination of stress profiles in NaK ion-exchanged glass optical waveguides

Abstract A method based on fracture mechanics rather than on the measurement of the refractive index and birefringence profiles, which determines stress profiles in NaK ion-exchanged soda-lime glass waveguides is presented and discussed. With this technique the stress profile is obtained by measuring the surface stress field by Vickers indentations on waveguides which are progressively HF leached, and the profile is subsequently corrected by considering successive reductions in the thickness.

Hybrid optoelectronic integrated circuit

The distribution of optical signals to a monolithic array of GaAs photoconductors by means of ion-exchanged glass optical waveguides is demonstrated. In this hybrid technique both optical and electronic interconnections of semiconductor elements are achieved through the use of a metallic interconnect layer deposited on the surface of a glass substrate which has a mating waveguide pattern. The low optical loss, ease of fabrication, and low material cost of diffused glass waveguides with such layers permit relatively large optoelectronic circuit boards to be made, in which numerous semiconductor active optoelectronic devices can be included. The device reported here serves as the signal distribution and cross-point switching section of an optoelectronic switch matrix.