MITSUBISHI

MITSUBISHI OPTICAL SEMICONDUCTORSMEASURING PROCEDURESII Cutoff frequencyT. G. 50 Q Micro strip line 470Tracking Q----/ 1-,-=-=-t====5~M~generatorLD50 Q Micro strip lineSpectrum analyzerM===::J--r----1 t----DAPDIIFig. 30 Cutoff frequency evaluating systemFig.30 is an example of the measuring set- up forfrequency characteristics.The Cutoff frequency fc (MHz) is the frequencyat which the signal level falls by 3dB.1m Pulse response characteristic of a monitorphotodiodePulsegeneratorSampling OscilloscopeFig. 31Monitor PD pulse response characteristicFig.31 an example of a measurement system formonitor PO pulse response characteristic.To minimize the losses use rnicro strip lines forthe connection on PG/LO and po/~sc.1 -32