The 6G transport network will be intricately designed as an integrated carrier, seamlessly integrating computing and networking capabilities. Leveraging the network as its foundation, it aims to deliver differentiated computing power services through supercomputing/intelligent computing and capability resource pooling. This study proposes an advanced modulation format, alternating polarization chirped return-to-zero frequency shift keying (Apol-CRZ-FSK), specifically designed to meet the integrated computing and networking carrying requirements of future 6G. Furthermore, comprehensive comparison and analysis of the transmission performance of 100 Gbps Apol-CRZ-FSK, CRZ-FSK, and differential quadrature phase shift keying (DQPSK) are conducted under identical conditions. The research indicates the high nonlinearity resistance capability exhibited by Apol-CRZ-FSK, highlighting its superior transmission performance.