Patent ID: 6192060
Filing Date: 2001-02-20
Classification: H01S,H04B

Abstract:
An optical transmitter, comprising:a laser for converting an electric signal into an optical signal;a pulse current driver for receiving an input signal and driving said laser according to a control signal inputted thereto separately;a bias circuit for cooperating with said pulse current driver to drive said laser in order to provide a bias for keeping an optical output level of said laser at a predetermined value;a mark-space ratio detector for detecting a mark-space ratio of the input signal;a photodiode for detecting back light of said laser and outputting monitor current of the optical signal;a current/voltage converter for converting the monitor current from said photodiode into a voltage;an average value detector for outputting an average value of the output of said current/voltage converter;a bias controller for comparing the average value with the mark-space ratio, amplifying a difference between the average value and the mark ratio and outputting a signal for controlling said bias circuit;an operation circuit for receiving the average value and the mark-space ratio and performing a predetermined operation; anda pulse current controller for comparing a result of the operation of said operation circuit with a fixed reference voltage, amplifying a difference obtained by the comparison and outputting the amplified difference as the control signal for said pulse current driver.