Silicon Nitride/Silicon Dioxide Echelle Grating Spectrometer for Operation Near 1.55 μm

Here we use an electron beam lithography system to pattern an Si
₃
N
₄
/SiO
₂
echelle grating using silver as a reflector on the grating grooves. The grating in this letter achieves 1.39 dB on-chip loss, a spectral resolution of ~1300, a 1.2 dB channel nonuniformity, and less than -30 dB adjacent channel crosstalk for the transverse electric field polarization. We establish that stitching errors can lead to appreciable adjacent channel crosstalk if proper precaution is not taken to minimize them.