Low cost ns LASER pulses

A simple and inexpensive circuit is described to produce nanosecond visible LASER pulses by fast modulation of a LASER diode. The pulse is initiated by a TTL pulse that is inverted and then ANDed with the initial pulse. The original and inverted pulse overlap for approximatly the propagation delay. These two pulses are ANDed togetehr, producing a pulse that does not saturate with a maximum voltage of 2.8 volts. This pulse is sufficient to drive the LASER DIODE, producing a pulse with a FWHM of 1.4ns and rise and fall times under 650 ps.
The circuit is built interdigitated-dead-bug style using DIP chips. The Inverter is glued to a grounding plane and the AND gate, also dead-bug style, soldered directly to the Inverter with the LASER diode soldererd between the pins of the AND gate. The direct soldering minimizes impedance mis-match and reduces reflections on the relevant time scale.