Impact Statement:A broadband AWG spectrometer with high spectral resolution requires large number of channels which increase the design difficulty, as both the insertion loss and the inte...Show More
Abstract:
Arrayed waveguide gratings (AWG) have been widely used as wavelength multiplexers and demultiplexers in dense wavelength division multiplexing communications. In this let...Show MoreMetadata
Impact Statement:
A broadband AWG spectrometer with high spectral resolution requires large number of channels which increase the design difficulty, as both the insertion loss and the inter-channel crosstalk become worse when more channels are included. The footprint of the device also expands nonlinearly. In our work, we optimize the device from the waveguide spacing, the receiver aperture at the end of the free propagation region, the geometry of the waveguide taper and the number of arrayed waveguides to achieve an ultracompact AWG design with low insertion loss and low inter-channels crosstalk. The AWG was fabricated and measured. The AWG had an operational bandwidth of 60 nm and channel spacing of 1.5 nm, which had a good agreement with our design objectives. The insertion loss varied from 0.6 dB to 1.3 dB across the central 20 channels and rose to 1.8 dB on the edge channels. The worst inter-channel crosstalk among the central 20 channels was 17.2 dB.
Abstract:
Arrayed waveguide gratings (AWG) have been widely used as wavelength multiplexers and demultiplexers in dense wavelength division multiplexing communications. In this letter, we describe a highly compact 40-channel AWG fabricated on the silicon nitride platform for operation with a center wavelength near 860 nm for use in spectral domain optical coherence tomography. The total footprint of the AWG is 910μm × 680μm. The transmission spectrum of the fabricated device was measured. The AWG had a channel spacing of 1.5 nm and optical spectral range of 60 nm, in accord with the design. The measured insertion loss was 1.3 dB for the central channels and 1.8 dB for the outmost channels. The inter-channel crosstalk varied from 17.2 dB to 19.7 dB for the central 20 channels.
Published in: IEEE Journal of Quantum Electronics ( Volume: 56, Issue: 1, February 2020)
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