Linearity of the M-Z modulator with the two-ring-assisted push-pull(TRAPP) configuration was studied under the loss influence.It was found that the linearity of the TRA-MZ modulator is greatly high,even at the low-loss condition.By properly setting the biasing phases,the 2~(nd)-and 3~(rd)-order harmonic terms of the modulation curves can be removed.The maximum linearity range is larger than 90% when the round-trip loss of the microrings is less than 6 dB.Analysis shows that the output phase of the microring-based all-pass filter will vary only within a limited range if the loss of the microring is very large,and the maximum modulation depth of the TRA-MZ modulator will be less than unit and become the major factor that reduces the linearity range though the modulation curve of the TRA-MZ modulator is still in high linearity within its modulation depth.