A wavelength selective switch (WSS) can route optical signals into any of output ports by wavelength, and is a key component of the reconfigurable optical add/drop multiplexer. We propose a wavefront control type WSS using silicon photonics technology. This consists of several arrayed waveguide gratings sharing a large slab waveguide, wavefront control waveguides and distributed Bragg reflectors. The structure, design method, operating principle, and scalability of the WSS are described and discussed. We designed and fabricated a 1 × 2 wavefront control type WSS using silicon waveguides. This has 16 channels with a channel spacing of 200 GHz. The chip size is 5 mm × 10 mm. The switching operation was achieved by shifting the phase of the light propagating in each wavefront control waveguide, and by controlling the propagation direction in the shared large slab waveguide. Our WSS has no crossing waveguide, so the loss and the variation in loss between channels were small compared to conventional waveguide type WSSs. The heater power required for switching was 183 mW per channel, and the average extinction ratios routed to Output#1 and Output#2 were 9.8 dB and 10.2 dB, respectively.

Abstract:The phase errors in 100-GHz spacing, 8-ch, Si-wire arrayedwaveguide gratings (AWG) fabricated by ArF-immersion photolithography were measured by the frequency-domain interference method. To our knowledge, this is the first time phase error measurements in a Si-wire AWG have been performed. By comparing the reconstructed transmission spectrum to the directly measured spectrum, the accuracy of this phase error measurement was confirmed. The average phase error in the AWGs on 6 chips was 0.27π radian, and this value is equivalent to a fluctuation in the effective refractive index of 1.1 × 10 −4.

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