METHOD OF MONITORING WAVELENGTH OF OPTICAL SIGNAL OUTPUT FROM LIGHT EMITTING ELEMENT AND OPTICAL SIGNAL MONITORING CIRCUIT

摘要

An optical signal monitor circuit is an optical signal monitor circuit including a PD which directly detects an optical signal and converts the optical signal into a photocurrent, a PD which detects the optical signal and converts the optical signal into a photocurrent, a resistance element which converts these photocurrents into voltages, and an operational amplifier which outputs the voltages generated by the resistance element, wherein the optical signal monitor circuit further includes a switching control circuit which switches a connection between the PDs and the resistance element, and a calculation circuit which acquires the output of the operational amplifier as a digital signal, the switching control circuit controls switching to flow the two photocurrents into the resistance element at individual timings and flow the two photocurrents into the resistance element at the same timing, and the calculation circuit calculates a corrected digital signal by subtracting the obtained digital signal.

主权项

1. A method of monitoring an output wavelength of an optical signal by converting photocurrents generated by two light receiving elements which receive the optical signal into digital signals corresponding to the respective photocurrents, the method comprising:
individually flowing the respective photocurrents into a resistance element and acquiring voltages generated in the resistance element through an operational amplifier as first and second digital signals; flowing the respective photocurrents into the resistance element at the same time and acquiring a voltage generated in the resistance element through the operational amplifier as a third digital signal; and acquiring a corrected digital signal by subtracting the second digital signal from the third digital signal and another corrected digital signal by subtracting the first digital signal from the third digital signal.