A ratiometric wavelength measurement based on a silicon-on-insulator directional coupler integrated device

A ratiometric wavelength measurement based on a Silicon-on-Insulator (SOI) integrated device is proposed and designed, which consists of directional couplers acting as two edge filters with opposite spectral responses. The optimal separation distance between two parallel silicon waveguides and the interaction length of the directional coupler are designed to meet the desired spectral response by using local supermodes. The wavelength discrimination ability of the designed ratiometric structure is demonstrated by a beam propagation method numerically and then is verified experimentally. The experimental results have shown a general agreement with the theoretical models. The ratiometric wavelength system demonstrates a resolution of better than 50 pm at a wavelength around 1550 nm with ease of assembly and calibration

Method of measuring monochromatic light wavelength by using wavelengthsensitiveoptical components

U ovoj doktorskoj disertaciji dat je predlog nove metode za merenje talasne dužine monohromatske svetlosti pomoću spektralno osetljivih optičkih komponenti. Princip rada predložene metode se zasniva na kombinovanju spektralnih osetljivosti fiber-optičke račve i dva različita fotodetektora. Izvršena je implementacija i karakterizacija senzorskog sistema za merenje talasne dužine monohromatske svetlosti. U eksperimentalnoj postavci korišćena je 2×2 fiber-optička račva, germanijumska (Ge) fotodioda i indijum-galijum-arsenid (InGaAs) fotodioda. Postignuta je linearnost sa faktorom korelacije R2=0.99942 i merna rezolucija od 17 pm u opsegu talasnih dužina svetlosti od 1575 do 1615 nm (L-opseg). U istom opsegu, dobijena je merna greška od približno ±0.2 nm i ponovljivost od ±0.16 nm. Ispitani su uticaji promena temperature, snage optičkog izvora i šuma na karakteristike senzorskog sistema.In this thesis, a new method for measurement of monohromatic light wavelength by using wavelength-dependent optical components is proposed. The principle of operation of the proposed method is based on combining spectral sensitivities of fiber-optic coupler and two different photodetectors. Sensor system for measurement of monochromatic light wavelength is implemented and characterized. Experimental setup consists of 2×2 fiberoptic coupler, germanium (Ge) photodiode and indium-gallium-arsenide (InGaAs) photodiode. Excellent linearity (R2=0.99942) and measurement resolution of 17 pm are achieved in measurement range 1575-1615 nm (Lband). In the same measurement range, measurement error of approximately ±0.2 nm and repeatibility of ±0.16 nm are obtained. The influence of temperature, optical source power and noise on sensor system characteristics is investigated