Vector characterization of photodetectors, photoreceivers, and optical pulse sources by time-domain pulse response measurements

Vacuum-Ultraviolet Photovoltaic Detector

“…Obviously, the ultrafast temporal response of the device is mainly attributed to the following reasons: (1) The built-in electric field formed between the graphene and AlN absorption layer rapidly separates the photogenerated carriers; (2) the high crystal quality of the AlN absorption layer reduces the probability of defects trapping carriers; and (3) the high mobility p-Gr offers a rapid collection and transmission of the photogenerated carriers (holes). , It should be mentioned that there is a relatively long tailing of the device attenuation time at the turn-off VUV light. This phenomenon is common in the pulse response test, which depends not only on the speed at which the device itself separates and collects the carrier but also on the internal impedance and capacitance effects of test circuit …”

Calibrated measurement of optoelectronic frequency response

“…The heterodyne method [18] is commonly used to measure . The normalized frequency response is defined as (12) where is the RF power the receiver delivers to a 50-load and is the dc photocurrent drawn by the receiver when illuminated by the constant component of the optical signal. The relations and give (13) where is the dc responsivity of the receiver, in amperes per watts, when driving a 50-load.…”

“…In [11], a VNA and a model of the modulator was used to estimate the phase response of the reference receiver. An oscilloscope whose response was derived from a model was used in [12] to estimate the phase response of a receiver. Also, oscilloscopes that were calibrated with the nose-to-nose method (described in [13] and [14]) were used to characterize the phase response of receivers in [15].…”

S‐matrix definition for microwave‐optical transducers

“…The arrays consist of M elements, the mth centred at r, with its axis oriented along u, (in polar coordinates ( a , p)). The field Ed radiated by the current Z(z') in a single dipole of length L is given by [2] Ed(r) = -- (1) where + ( r ) = e C k 7 r . Currents in the array elements induced by an arbitraly incident field E'(r) are expanded as a series of known functions, I,(z') = EF= C,,f,(z').…”

“…It yields a vectorial linear relation between the microwave current and the alternate component of the optical intensity (modulated part of the intensity). Work by Hawkins et al [2] in the time domain and by Vifian [3] in the frequency domain are based on this small-signal approach. Meanwhile, they handle the transmission of the transducer without using the S-matrix formalism.…”