News: Optoelectronics
12 April 2022
CompoundTek demos hybrid silicon O+C+L-band wavelength-tunable laser module
At the recent LUX-Enterprise Singapore Copackaged Photonics/ASICs & Heterogeneous Integration Workshop, Singapore-based silicon photonic (SiPh) foundry services provider CompoundTek Pte Ltd shared results on a hybrid silicon O+C+L-band wavelength-tunable laser module that a stealth-mode product company ran with CompoundTek.
Through the development of the hybrid silicon laser technology, CompoundTek’s team – led by chief operating officer KS Ang and principal engineer Dr Brian Sia together with key personnel from the stealth-mode product company – is claimed to be one of the first in the world to realise laser engines that operate simultaneously in the O, C and L wavebands. The laser engines have a wavelength tuning range of 175nm across the three wavebands, with an output power and side-mode suppression ratio (SMSR) as high as 40mW and 50dB, respectively.
As a corollary to advanced silicon manufacturing, silicon photonics has emerged as one of the fastest-growing technologies, says CompoundTek. However, due to the material properties of silicon, the realisation of laser sources has represented one of the final frontiers in the area. ‘Lighting up Silicon’ is thus a strategically imperative initiative that needs to be urgently addressed, the firm adds.
The primary advantage of a wavelength-tunable laser lies in its ability to reduce the complexity of optical systems; a single wavelength-tunable laser can be used to replace an array of single-wavelength lasers, simplifying the system architecture as well as lowering inventory cost.
While distributed feedback (DFB) laser arrays and micro-electro-mechanical systems (MEMS) vertical-cavity surface-emitting lasers (VCSEL) have been shown to demonstrate wavelength-tuning functionality, there are limitations in terms of DFB array coupler loss and mechanical instability, respectively. Littman/Littrow-configured external-cavity lasers (ECLs) have also exhibited a wide operating wavelength range; however the application space of this class of lasers is limited by their bulk, as well as greater vulnerability to environmental vibrations.
“The challenge is for the development of a solid state-based laser diode with compact footprint, and good performance that can be manufactured in a scalable, high-yield and low-cost process,” says KS Ang. “While there are many ways to build a tunable laser, what sets CompoundTek’s technology apart is our ability to integrate with silicon photonics devices which offer low propagation loss and high integration densities,” he adds.
