Mode-matched ion-exchanged glass-waveguide bridge for high-performance dense wavelength division multiplexer

Data bit rate, 1-dB passband, and device dimensions are the key properties of dense wavelength division multiplexing (WDM) devices. For blazed-grating-based dense WDM devices, analysis shows that all these three properties can be enhanced by reducing the output fiber-array channel spacing. In this paper, we propose an ion-exchanged glass waveguide to reduce the output channel spacing. To fabricate the low-loss fiber-compatible waveguide, a field-assisted ion-exchange process is developed. The waveguides fabricated by this process have a propagation loss of 0.16 dB/cm and a coupling loss to single-mode fiber (SMF) of 0.1 dB. A 47-channel 100-GHz-spacing dense WDM integrated with the glass waveguide is then packaged and demonstrated. The device performance has verified the effectiveness of the proposed solution and the successfulness of the ion-exchanged glass-waveguide technique in this application.