摘要 |
<p>A wavelength-division lightwave multiplexing device, and method of its manufacture, having an embedded filter and two parabola-shaped crossing waveguides, the waveguides providing collimation of light transmitted therein. At least one of the parabola-shaped wave crossing waveguides includes a first port, and a second port, and a widened portion between the first and second ports having a parabola-shaped profile, wherein the widened portion widens from the first port toward a midpoint thereof, and then narrows to the second port. The invention achieves low insertion loss and high spectral isolation while keeping a narrow guard band smaller, and addresses the problem of poor spectral isolation characteristics in the filter-embedded waveguide WDM device when it is adopted to applications requiring a guard band narrower.</p> |