METHOD FOR CALCULATING APPLIED VOLTAGE AFTER LONG-TERM USE OF WAVEGUIDE TYPE OPTOELECTRIC DEVICE AND METHOD FOR APPLYING THE CALCULATING METHOD

摘要

PROBLEM TO BE SOLVED: To provide a method for calculating in advance an applied voltage after long-term use of a waveguide type optoelectric device, and a method for selecting an element of which the long-term drift property is stable, by using the method. SOLUTION: An initial DC bias voltage Vo is applied to a device at a temperature T, and a voltage to keep the optical output of the device in the initial state is recorded in relation to the elapsed time, and the ratio A(t)=V(t)/Vo of an applied voltage V(t) at time t to the bias voltage Vo is calculated at plural points of time to generate a relational formula between the time t and the voltage A(t), and the ratio A(t) at a desired time t1 is calculated in accordance with the relational formula, and the value of Vo×A(t1) is taken as the value of the voltage V(t1) which should be applied to the device at the time t1. This method is used to repeat the operation, where the value of A(t)=Vt/Vo is calculated at plural times of point, twice or more, and if this value is three or smaller at all points of time, this device is selected as a device of which the long-term drift property is stable.