Grant: Research Tools and Instruments

This application proposes to purchase a tunable laser and associated optical detectors needed to characterize novel photonic devices that the applicants are developing using silicon chips operating at optical wavelengths near 1.3 µm. The laser and a set of detectors are urgently needed to support three recently awarded major research project grants in quantum communication, optical communications in data centres, and biosensors. In addition, two single photon detectors are required for the quantum communications project. * Most research in silicon photonics to date has been focused on wavelengths near 1.55 µm, known as the C-band. This band was chosen for long distance optical telecommunications primarily due to the availability of erbium-doped fibre amplifiers. Due to the plethora of components available for this industry (optical amplifiers, filters, optical fibres, modulators, detectors, and lasers), it was natural for silicon photonics researchers to develop components at this standard wavelength. However, there are applications where other wavelengths are more suitable. The first is short-reach optical communications where optical amplifiers are not required. We are not constrained to 1.55 µm and instead can operate at 1.31 µm, the O-band, where the dispersion of digital pulses is minimized. Thus, silicon photonic systems for data centres are being implemented using 1.31 µm, and we aim to develop a library of components that we fabricate and test at UBC. * For quantum optics, we seek a wavelength that is most suitable for developing on-demand high-purity single photon sources. There exist several defect states in silicon that can emit light near 1.3 µm (e.g., G-centre). The G-centre shares many of the properties that make nitrogen vacancies in diamond useful as quantum emitters for single photons. Our objective is to develop single photon sources and single photon detectors, and to build a prototype quantum key distribution (QKD) system implemented in silicon. This will require characterizing photonic crystal resonators using a tunable laser and detector, then characterizing the single photon emission properties of the defects added to the photonic crystal cavities using a single photon detector system. The latter step will also involve the same tunable laser source, for resonant excitation. * The third application is for biosensors. Our research in biosensors is currently being commercialized at a wavelength of 1.55 µm. Sensors in aqueous media (blood, saliva) will perform 10X better at 1.3 µm than at 1.55 µm due to reduced water absorption. Our aim is to research systems at a 1.3 µm wavelength with improved sensitivity. This project shares similar device design and test requirements as the two other applications, namely the development of a library of components such as fibre coupling, splitters, and filters, all which need to be characterized using a tunable laser and detector system, and with an Optical Vector Network Analyzer.*