We report on improved gain and spectral control in co-extruded all-polymer multilayer distributed feedback (DFB) lasers achieved by folding and deliberate modification of the center "defect" layer. Because DFB laser gain is greater at spectral defects inside the reflection band than at the band edges, manipulation of structural defects can be used to alter spectral defects and thereby tune the ...

The results of an investigation of the performance of a time-division-addressed fiber-optic gas-sensor array by means of wavelength modulation of a distributed-feedback (DFB) laser are reported. The system performance is found to be severely limited by the extinction ratio of the optical switch used for pulse amplitude modulation. Formulas that relate the cross-talk level to the extinction rati...

We demonstrate an optical amplification of organic dye within a TiO2 inverse-opal (IO) distributed feedback (DFB) reflector prepared by a slide-coating method. Highly reflective TiO2 IO film was fabricated by slide coating the binary aqueous dispersions of polystyrene microspheres and charge-stabilized TiO2 nanoparticles on a glass slide and subsequently removing the polymer-opal template. TiO2...

Reproductive information since 1995 from the USDA national dairy database was used to calculate yearly Holstein and Jersey means for days to first breeding after calving (DFB), 70-d nonreturn rate, conception rate (CR), number of breedings per lactation (NB), interval between first and last breedings during the lactation, days to last breeding after calving (DLB), pregnancy rate (PR), calving i...

Computer graphics is a new science produced with the popularization of computers. The processing technology and images in computer has attracted much attention. How to make reasonable use them become an important subject field modern scientific applications. For this research background, paper proposes image recognition algorithm based on wavelet DFB-PCA. After decomposing transform, DFB-PCA pe...

High-coupling (KL = 3.0) phase-shifted DFB lasers are studied using a transmission-line laser model (TLLM), which includes spatial hole burning (SHB), the material gain spectrum, refractive index dependence on carrier concentration, and random spontaneous emission. Good agreement for CW spectra is shown with other models and experimental results. Dynamic simulations of laser transients show SHB...

We present our theoretical model and experimental results on the extreme linewidth narrowing of an erbium-doped fiber distributed feedback (DFB) laser due to additional random DFB via Rayleigh backscattering in a long single-mode connected laser. The relative instantaneous (<1 ?s) such hybrid cavity configuration predicted by may exceed six orders magnitude, whereas estimated from phase nois...

A novel high power distributed feedback (DFB) laser is proposed which uses a partially narrow waveguide and corrugation pitch modulated (CPM) phase shift grating. Compared with conventional DFB lasers constant width, these necked have greater improvements in terms of optical relative intensity noise (RIN) spectrum. They are less sensitive to external (EOF) increase the range injection current f...

Conventional push-pull modulated (PPM) distributed feedback (DFB) lasers exploit structures with symmetry, which wastes a significant amount of the optical power output from rear facet. To improve efficiency, PPM DFB asymmetrically coated facets can be considered. However, resulted imbalanced modulation causes dip in device small-signal intensity response near carrier-photon resonance (CPR) fre...