Patent ID: 9628142
Date: 2017-04-18
CPC Classifications: H04B

Claim:
1. An optical transmitter comprising: at least two laser diodes (LDs) configured to generate respective optical signals in response to respective driving signals; driving circuits configured to generate the respective driving signals; photo detectors (PDs) configured to convert the respective optical signals to respective first electrical signals and output the respective first electrical signals; a switch configured to select one first electrical signal of the respective first electrical signals according to a selection signal and configured to output the one first electrical signal as a second electrical signal, the switch providing first input terminals and a first output terminal, the first input terminals being configured to receive the respective first electrical signals one-to-one, the switch electrically connecting one of the first input terminals to the first output terminal and thereby outputting the second electrical signal; and a controller configured to generate the selection signal and control one of the driving circuits in response to the second electrical signal so as to maintain an intensity of one optical signal of the respective optical signals at a predetermined value, the one optical signal being generated by one of the LDs that is driven by the one of the driving circuits, wherein the controller generates the selection signal, so that the switch connects each of the first input terminals to the first output terminal one by one at a time interval, wherein the PDs provide respective second output terminals configured to output the respective first electrical signals, wherein the controller includes a second input terminal configured to receive the second electrical signal from the switch, and wherein the optical transmitter further includes first wirings that electrically connect the respective second output terminals to the first input terminals one-to-one and a second wiring that electrically connects the first output terminal to the second input terminal, the first wirings having respective lengths between the respective second output terminals and the first input terminals, each of the lengths being shorter than a length of the second wiring between the first output terminal and the second input terminal.