An asymmetric waveform signal generation scheme based on dual polarization multiplexing-quadrature phase shift keying (PM-QPSK) modulator is proposed and analyzed. The key technique to generate periodic asymmetrical function waveform is how to control the amplitude and phase of the Fourier series of the target waveform simultaneously. In order to achieve this function in this proposal, a continuous-wave laser is modulated by radio-frequency signals with various phases, using a PM-QPSK modulator. The orthogonal sine and cosine harmonic signals are output through a polarization beam combiner. A polarizer is then employed to balance the power of these two orthogonal signals. By properly adjusting the variables, both the amplitude and phase of the Fourier series of the target waveform can be simultaneously set. When the root mean square error is <5%, a half duty cycle ramp wave signal with adjustable slope (20%≤δ≤80%) can be obtained. In addition, the influence of variable drift on the target waveform is analyzed in detail.