Detection at Gbit/s rates with a TJS GaAlAs laser

Feasibility has been shown for using a GaAl-GaAlAs Transverse Junction Stripe (TJS) laser as a high performance optical detector. The impulse response of the device was measured to be 170 ps (FWHM), corresponding to a receiver capability of 5 Gbit/s (NRZ). The responsivity at the operating wavelength of the laser/detector (900 nm) and at a reverse bias voltage of 3 V was 0.1 A/W. As a comparison, measurements on a narrow-stripe DH laser showed an impulse response of 6 ns (FWHM) and a responsivity of 0.06 A/W. Using identical structures for both the laser and the detector offer a promising approach to monolithic integration.