A novel 1.3 mu m MQW light-emission-and-derection diode including a bulk detection layer is proposed for use in time-compression-multiplexing transmission systems. In the lasing mode. this diode has a threshold current of 9mA at 25 degrees C and a maximum output power of > 10 mW at 85 degrees C. In the detection mode: the polarisation dependence of its responsivity, as a detection operation: is < 0.5 dB and the wavelength dependence of the responsivity is only 1 dB at a wavelength 35nm longer than the lasing wavelength.