We experimentall y studied different laser mode—locking techniques. These stud—

Equivalent capacitance photodiode determination by an optical methodAdrian 6h1 Podoleanu, Paul E. Sterian, Ion M. Popescu, Nicolae N PuscasPhysics Department, Polytechnical Institute of BucharestSpi. Independentei 313, Bucharest 77206, RomaniaABSTRACTThe paper deals with a dynamic method for measuring the photodiode equivalentcapacitance and its dependence on voltage applied Based on an original and inexpen—sive mode—locking technique, the method uses a computer evaluation of the measuredresponse pulse shape for a certain value of the photodiode inverse bias voltages1. INTRODUCTIONWe experimentally studied different laser mode—locking techniques. These stud—ies permitted us to put in the order very simple short optical pulse generators1 Thesimplicity of the implemented configurations consists in a very small alterations ofthe active laser cavity. Thus, we used a passive cavity coupled to the active cavityand all the required adjustment operations did not affect the active cavity. It was