Pre-equalized optical transmitter and pre-equalized optical transmission method

摘要

A pre-equalization optical transmitter includes: a tap coefficient selecting unit for saving, in advance, a tap coefficients for generating an RZ pre-equalization signal and an NRZ pre-equalization signal, and for selecting and outputting one of the tap coefficients according to the value of a parameter that is a factor of transmission power fluctuations; a pre-equalization signal generating unit for generating the RZ pre-equalization signal or the NRZ pre-equalization signal based on the tap coefficient; and a modulating unit for generating a pre-equalization optical transmission signal by modulating an optical signal input from a light source by using a signal obtained through D/A conversion and amplification of the RZ pre-equalization signal or the NRZ pre-equalization signal, wherein a transmission method is switched between an RZ method and NRZ method by switching the tap coefficients by the tap coefficient selecting unit.

主权项

1. A pre-equalization optical transmitter, which uses an RZ method and an NRZ method both as a method of transmission by switching from one method to another, comprising:
a tap coefficient selecting unit for saving in advance a tap coefficient for generating an RZ pre-equalization signal which is used in the RZ method and a tap coefficient for generating an NRZ pre-equalization signal which is used in the NRZ method, and for selecting and outputting one of the tap coefficient for generating the RZ pre-equalization signal and the tap coefficient for generating the NRZ pre-equalization signal according to a value of a parameter that is a factor of fluctuations in transmission power; a pre-equalization signal generating unit for generating the RZ pre-equalization signal when the tap coefficient output from the tap coefficient selecting unit is the tap coefficient for generating the RZ pre-equalization signal, and generating the NRZ pre-equalization signal when the tap coefficient output from the tap coefficient selecting unit is the tap coefficient for generating the NRZ pre-equalization signal; a digital-analog conversion unit for converting the RZ pre-equalization signal or the NRZ pre-equalization signal output from the pre-equalization signal generating unit into an analog signal; an amplifying unit for amplifying the analog signal output from the digital-analog conversion unit; a light source for outputting an optical signal; and a modulating unit for generating a pre-equalization optical transmission signal by modulating the optical signal input from the light source based on the amplified analog signal which is output from the amplifying unit, wherein the tap coefficient selecting unit switches the tap coefficients according to the value of the parameter, thereby switching the method of transmission between the RZ method and the NRZ method during transmission.