LED’s electrical equivalent circuit.
Principle of LED-based short pulse generation exploiting the peaking and carrier sweep-out effects and the bias voltage dependence of output optical pulse width and peak power. 16 (a) The pulse generation is affected by long rise and decay times of the EL pulse without peaking and carrier sweep-out effects (b) The peaking and carrier sweep-out effects without applied bias voltage (V biasLED = 0). (c) The peaking and carrier sweep-out effects with applied bias voltage (0 < V biasLED ⩽ V built − in ).
(a) The conceptual circuit diagram of the optical pulse generator using current-shaping circuit. (b) I-V characteristic of resistive branch of the current-shaping circuit.
The circuit diagram of the sub-nanosecond optical pulse generator. The SRD-based generator which uses a 10 cm short-circuited RG-316 coaxial cable with v p ∼ 2 × 108 m/s is followed by the 2SD-C current-shaping circuit.
Schematics of the experimental setup for time-resolved measurements.
Measured optical pulses for the 405 nm LED at different bias voltages. The repetition rate is 80 MHz. (Inset) The bias voltage dependence of pulse width and peak power of the output pulses.
Measured optical pulses for the UV LEDs: UVTOP290 (a), UVTOP315 (b), and UVTOP335 (c) at different bias voltages. The repetition rate is 80 MHz. (Insets) the bias voltage dependence of the output pulse width.
Summary of measured results in comparison with commercial generators.
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