Characteristics of 1.3- mu m InGaAsP lasers used as photodetectors

The photodetection capabilities of 1.3- mu m channel substrate lasers are studied. The diodes can be used either as lasers or detectors in single-mode-fiber half-duplex communication links. As a detector, a responsivity of 0.26 A/W is obtained by efficiently coupling the input radiation into the facet using a lensed single-mode fiber. The spectral bandwidth extends from 1.1 to 1.37 mu m. The dark current at room temperature is 200 nA at 1-V bias and due in part to current leakage through the Fe-doped InP blocking layer. As lasers, the diodes have a frequency response of 4 GHz, and as detectors, the 3-dB bandwidth is 600 MHz.<
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