Silicon nanomembrane based photonic crystal waveguide array for wavelength-tunable true-time-delay lines

We demonstrate a four-channel on-chip true-time-delay module based on a photonic crystal waveguide array. Using the photonic crystal taper to minimize the coupling loss, the delay lines with 1–3 mm long photonic crystal waveguides can operate up to a group index ng ∼ 23 without significant loss. The large group velocity dispersion enables continuous and wavelength-tunable time delays. Measurements show a highly linear phase-frequency relation, highest time delay up to 216.7 ps, and large tuning ranges of 58.28 ps, 115.74 ps, and 194.16 ps for 1–3 mm delay lines. The chip-scale true-time-delay module occupies only 0.18 mm2 area and can provide ±44.38° steering for an X-band phased-array-antenna.

[1]  Ray T. Chen,et al.  Optimum access waveguide width for 1 x N multimode interference couplers on silicon nanomembrane. , 2010, Optics letters.

[2]  T. Krauss,et al.  Ultracompact and low-power optical switch based on silicon photonic crystals. , 2008, Optics letters.

[3]  Ray T. Chen,et al.  Wideband group velocity independent coupling into slow light silicon photonic crystal waveguide , 2010 .

[4]  Ray T. Chen,et al.  Electro-optic polymer infiltrated silicon photonic crystal slot waveguide modulator with 23 dB slow light enhancement , 2010 .

[5]  Ray T. Chen,et al.  Photonic crystal slot waveguide absorption spectrometer for on-chip near-infrared spectroscopy of xylene in water , 2011 .

[6]  Alwyn J. Seeds,et al.  Optically generated true-time delay in phased-array antennas , 1995 .

[7]  R.T. Chen,et al.  Photonic Crystal Fiber-Based True-Time-Delay Beamformer for Multiple RF Beam Transmission and Reception of an X-Band Phased-Array Antenna , 2008, Journal of Lightwave Technology.

[8]  L. O'Faolain,et al.  Tunable Delay Lines in Silicon Photonics: Coupled Resonators and Photonic Crystals, a Comparison , 2010, IEEE Photonics Journal.

[9]  Ray T. Chen,et al.  On-chip methane sensing by near-IR absorption signatures in a photonic crystal slot waveguide. , 2011, Optics letters.

[10]  Toshihiko Baba,et al.  Slow light in photonic crystals , 2008 .

[11]  Thomas F. Krauss,et al.  Low-loss propagation in photonic crystal waveguides , 2006 .

[12]  Ray T. Chen,et al.  Photonic dual RF beam reception of an X band phased array antenna using a photonic crystal fiber-based true-time-delay beamformer. , 2008, Applied optics.

[13]  Xiaolong Wang,et al.  Effective in-device r33 of 735 pm/V on electro-optic polymer infiltrated silicon photonic crystal slot waveguides. , 2011, Optics letters.

[14]  Wolfgang Freude,et al.  High-speed low-voltage electro-optic modulator with a polymer-infiltrated silicon photonic crystal waveguide. , 2008, Optics express.