A tunable 1x4 silicon CMOS photonic wavelength multiplexer/demultiplexer for dense optical interconnects

Abstract

We report the first compact silicon CMOS 1x4 tunable multiplexer/ demultiplexer using cascaded silicon photonic ring-resonator based add/drop filters with a radius of 12 microm, and integrated doped-resistor thermal tuners. We measured an insertion loss of less than 1 dB, a channel isolation of better than 16 dB for a channel spacing of 200 GHz, and a uniform 3 dB pass band larger than 0.4 nm across all four channels. We demonstrated accurate channel alignment to WDM ITU grid wavelengths using integrated silicon heaters with a tuning efficiency of 90 pm/mW. Using this device in a 10 Gbps data link, we observed a low power penalty of 0.6 dB.

Fabrication-Tolerant Four-Channel Wavelength-Division-Multiplexing Filter Based on Collectively Tuned Si Microrings

“…For one channel this corresponds to 74 mW/FSR for the filter design with 1RR and 101 mW/FSR for 2RR, which are comparable with other reported values, e.g. 89 mW/FSR in [8]. As demonstrated in [10], these efficiencies can drastically be improved using a top-side silicon undercut-etching technique, resulting in a 2.4 mW/FSR.…”

“…Uniform local heating of the WDM filter is demonstrated using carefully designed p-type doped silicon heaters. Collective tuning would require only a single thermal control circuit for each WDM filter, as compared to an individually tuned WDM filter array on a 200 GHz grid as proposed in [8]. This reduced complexity for thermal control will likely reduce the power and footprint overhead of the required CMOS control circuits, which will be beneficial when scaling to higher channel counts.…”

Silicon Nanowire Waveguides and Their Applications in Planar Wavelength Division Multiplexers/Demultiplexers

“…11. Four-channel demultiplexer using ring resonators with different bend radius (Bogaerts et al, 2006) 14 Another fabricated 1x4 WDM multiplexer/demultiplexer with integrated thermal tuning is shown in Figure 12 (Zheng et al, 2010). Instead of using rings slightly different in size to achieve filters with different central wavelengths, identical rings with integrated thermal tuning are used.…”

“…12. Fabricated 1x4 multiplexer/demultiplexer by cascading 4 ring add/drop filters with integrated doped resistor thermal tuner (shown in the inset SEM picture) using FreeScale 130 nm CMOS process (Zheng et al, 2010) 3.2 Multiple-channel multiplexers/demultiplexers using silicon nanowire platform Although planar filters are enough simple and effective for the applications of wavelength multiplexing and demulitplexing, they have to be cascaded to support multiple operated wavelength channels, which increase the insertion loss and the noise. AWGs and EDGs are two typical multiplexers/demultiplexers based on planar integrated optical waveguides, which can offer more than 40 channels of dense WDM.…”

Thermo-optic switch based on transmission-dip shifting in a double-slot photonic crystal waveguide

“…High Q microring resonator could be a solution, but it is very sensitive to thermal fluctuations or fabrication imperfections, and also the operating bandwidth is very narrow. 5,8,9 Another one is photonic crystal waveguide (PCWG) with the help of slow light effect, which could be achieved with a flexible design of the photonic band structure. [10][11][12][13] There are two operating mechanisms reported for the PCWG based optical switches.…”