Narrow Results

Substrate removing technique is proposed in silicon Mach–Zehnder modulator (MZM) to improve the electro-optic bandwidth. Based on this technique, a silicon MZM with 3 dB electro-optical bandwidth of 55 GHz is achieved at 5 V reverse bias for the first time. The V$\pi \cdot$ L of the modulator is 1.3 V$\cdot$cm with an on-chip insertion loss of 5.4 dB. The substrate removing technique reduces the electrode transmission loss, achieves the electro-optical group index matching and realizes 50 $\mathrm{\Omega }$ impedance matching, simultaneously. In this work, we experimentally demonstrate BPSK modulation based on this modulator at the baud rate up to 56 Gb/s.

The carrier lifetime in SiGe planar waveguides with Si cladding was measured with a pump-and-probe technique, using an ultrashort 810 nm laser pulse and a CW 1.55 μm probe, as a function of layer thickness d and Ge concentration x. The measured lifetimes are in the range of 20-90 ns. The obtained interface recombination velocity S is a growing function of both d and x, taking values in the range from 300 to 4000 cm/s.

In this paper we propose and analyze numerically an hybrid nonlinear microring structure implemented in a silicon-on-insulator (SOI) platform with a cover of organic material. We study its (off-resonance) bistable switching behavior, as well as its resonant operation (add-drop), and asses the effect of the organic material, namely 2-[4-(dimethylamino)phenyl]-3-{[4-(dimethylamino)phenyl]ethynyl} buta-1,3-diene-1,1,4,4-tetracarbonitrile, in the device performance.

In this paper, we report the insertion loss and adjacent crosstalk for tapered and conventional configuration of double S-shaped design of arrayed waveguide grating (AWG) using 1.2 μm and 1.0 μm core width. The 13-channel AWG on silicon-on-insulator (SOI) was simulated using beam propagation method (BPM) at central wavelength of 1.49 μm, producing a transmission spectrum ranging from 1310–1620 nm. Tapered AWG for both core widths gave the lowest insertion loss of < 7 dB while only the AWG with the 1.2 μm core width produced the lowest crosstalk at < -19 dB compared to the other configurations. A 13-channel transmission spectrum of the AWG device has been produced which fits closely the standard ITU-T CWDM wavelength grid.

Photonics/optoelectronics research at Glasgow University is partially reviewed. The research activity reviewed is also notably connected to research groups furth of Glasgow. Silicon waveguide photonics at the sub-micrometre/nanometre scale is emphasized, including photonic wires, strong Bragg gratings and micro-/nano-cavity resonators and slow light in photonic crystal channel waveguides. High-volume processes for the fabrication of photonic quasi-crystal structures that enhance and shape the light extracted from GaN blue LEDs will also be described. Finally split-ring resonator (SRR) array based metamaterials are featured - together with their application for organic sensing.