ABSTRACT
A uni-traveling carrier photodetector (UTC-PD), heterogeneously integrated on silicon, is demonstrated. It is fabricated in an InP-based photonic membrane bonded on a silicon wafer, using a novel double-sided processing scheme. A very high 3 dB bandwidth of beyond 67 GHz is obtained, together with a responsivity of 0.7 A/W at 1.55 µm wavelength. In addition, open eye diagrams at 54 Gb/s are observed. These results promise high speed applications using a novel full-functionality photonic platform on silicon.
ABSTRACT
Neural adaptation to light stimulation in the dark-adapted retina can be demonstrated by double-flash electroretinography. The first flash is a conditioning flash, the second flash is the test flash. Interstimulus intervals are in the range of 0.2 to 30 seconds. Suppression of the response to the test flash is assumed not to be related to photopigment regeneration, as in normal human subjects the recovery after strong conditioning flashes is completed in about 2 seconds. In this paper we demonstrate the results of double-flash electroretinography on four patients, two of whom are brother and sister. Each of them showed a five- to ten-fold prolonged suppression time compared to normal measurements. Clinical aspects of all the patients were a stationary, though fluctuating, subnormal visual acuity of about 0.5, some photophobia, and difficulties in adaptation to changes in luminance levels. We assume that the PERRS indicates changes in the restorative reactions to phototransduction in the photoreceptors, or in the neural transmission mechanism, either in the rod-driven lateral inhibitory neural processes or in the cone-driven rod inhibitory processes, caused by a cone dysfunction.
