Fig. 1. Schematic diagram of the imaging spectrometer, where the arrayed-input EDG is used. Lens 1 represents the fore-optic lens, and the micro-electromechanical system (MEMS) mirror array operates as an optical switch array for N pixels. The chip structure is enlarged, and the arrayed input waveguides receive the N corresponding pixels one by one. Thus, the spectrum of each pixel is obtained in a time division multiplexing fashion.

Fig. 2. (a) Scanning electron microscope (SEM) images of the cross-section of a deep etched strip waveguide, (b) cross-section of a shallow etched ridge waveguide, (c) tapers between ridge waveguides and deep etched strip waveguides, (d) cross-section of the Al coated surface, and (e) the grating facets of the EDG. (f) The photograph of the EDG chip compared with one yuan coin.

Fig. 3. (Color online) Transmission spectra for (a) input waveguide No. 1, (b) input waveguide No. 33, and (c) input waveguide No. 65. The enlarged spectra for output channel Nos. 32 to 34 of input waveguide No. 33 are given in (d), showing the detailed polarization insensitive characteristics.

Table 1. Design Parameters of the EDG