Abstract: A characterization circuit for an optical device includes: an optical device, a switch, a switch driver, one or more resistors, and one or more capacitors. The switch driver is configured to receive a trigger pulse from an external pulse generator and to provide the trigger pulse to the switch, which causes the switch to be in an on state. The one or more capacitors are configured to, when the switch is in an off state, receive a charge current (e.g., with a greater than 50 nanoseconds rise time) from an external driver voltage source via the one or more resistors; and, when the switch is in the on state, discharge a current pulse (e.g., with a less than 10 nanosecond pulse width) to the optical device. The optical device is configured to receive the current pulse and to emit, based on the current pulse, an optical output pulse.