Fig. 1. (a) Schematic diagram of the CPMWA structure. Inset (i) shows variable output waveguide spacing. Inset (ii) shows the design and optical field mode of the waveguide. (b) Schematic diagram of the star coupler. (c) Schematic diagram of the reconfigurable module.

Fig. 2. (a) Electric field amplitude obtained through the beam propagation simulation of the star coupler. (b) The electric field amplitude at the end of the simulated region shows the Gaussian envelope of the illumination pattern of the tapered waveguide as sampled by the waveguide array.

Fig. 3. Experimental setup of the CPMWA spectrograph. MO, microscope objectives; SL, spherical lens.

Fig. 4. (a) Captured spectral lines at different wavelengths of the CPMWA spectrograph. (b) Spectrum measured with the CPMWA spectrograph. (c) Measured and fitted spectrum with an FWHM of 2.0 pixels at 1550 nm.

Fig. 5. (a) Near-field images of the output facet of the CPMWA. (b) Normalized light transmission of the 80 waveguides in the CPMWA chip. (c) The line spread function of the CPMWA spectrograph is calculated from the theoretical (blue line) and measured transmission (red line).

Fig. 6. (a) Spectrum reconstruction overall process. L_i represents the designed length of the ith waveguide. (b) Phase error detection. (c) Spectrum reconstruction process.

Fig. 7. (a) Ideal spectrum. (b) Measured spectrum. (c) Corrected spectrum, contrast up to 20 dB.