Regular papers

Optical modelling of a Si-based DBR laser source using a nanocrystal Si-sensitized Er-doped silica rib waveguide in the C-band

¹ Dipartimento di Elettrotecnica ed Elettronica, Politecnico di Bari, Via Re David 200, Bari, Italy
² UCC Department of Physics, University College Cork, Lee Maltings, Prospect Row Cork, Ireland

^* c.ciminelli@poliba.it

Received: 4 February 2008

Abstract

The availability of reliable silicon-based laser sources is at the basis of the integration of photonic and microelectronic devices on a single chip with consequent development of wavelength division multiplexing telecommunication systems.

A high efficiency Si-based laser source with good stability at room temperature would encourage and push the large scale of integration of electronic and photonic devices within a single chip.

Several techniques have been proposed for generating light with an internal quantum efficiency some order of magnitude greater than that typical of silicon (10⁻⁶) by using either electrical or optical pumping. Among them we mention the improvement of some fabrication process steps, reduction of the channels of non-radiative recombination, quantum confinement, the use of silicon nanocrystals (Si-ncs) incorporated in a silica matrix. This last technique is used in combination with Er³⁺ doping to generate light emission around 1500 nm in silicon, since Er-doped Si-ncs behave as electron-hole pairs trap, and the presence of Er shifts the emission peak to around 1500 nm.

In this paper we have pointed out the optical model of a Si-based DBR laser including a Si-ncs Er-doped SiO₂ rib waveguide, working at a wavelength in C-band. In particular, after a brief description of the structural and optical properties of the silicon crystals, we report on the model and design of the Er:Si-nc/SiO₂ rib waveguide, of the optical cavity and of the Bragg mirrors.