Research Review: PICs Could Benefit From Square Lasers
A team of researchers at the Chinese Academy of Sciences has built the first square microlasers featuring output ports on opposite corners.
These devices that are produced by planar processes could provide a key building block for the fabrication of photonic integrated circuits (PICs).
The shape of microdisk lasers governs the direction of their emission. Square lasers with output ports in the corners were investigated, because this design can realize highly confined modes while still producing directional emission.
Fabrication of the structures begins by using plasma enhanced CVD to deposit an 800 nm-thick SiO2 film onto the top of epitaxial laser structures grown on InP. Photolithography defines the profile of the laser, before plasma and wet etching techniques remove the oxide film. A second SiO2 layer is then deposited, with further photolithography and etching steps defining a window in the cavity. The addition of Ti/Au and Au/Ge/Ni contacts creates n and ptype electrodes.
A 1514 nm laser created by this process delivered 4.8 μW at a 72 mA injection current. “It’s only a concept device, and the threshold current and output power are not good enough for making photonic integrated circuits yet," explains corresoponding author Yong-Zhen Huang.
He says that the team will now focus on reducing the threshold current and increasing the output power of its microlasers.
“We are now investigating coupled circular resonators, which can have over 99 percent coupling efficiency, according to finitedifference time-domain simulations," says Huang.
The two-port square microlaser has 20 μm sides and output waveguides on opposite corners. Credit: CAS.
K-J. Che et al Electron. Lett. 46 585 (2010)
AngelTech Live III: Join us on 12 April 2021!
AngelTech Live III will be broadcast on 12 April 2021, 10am BST, rebroadcast on 14 April (10am CTT) and 16 April (10am PST)
and will feature online
versions of the market-leading physical events: CS International
and PIC International
PLUS a brand new Silicon Semiconductor International
Thanks to the great diversity of the semiconductor industry, we are always chasing new markets and developing a range of exciting technologies.
2021 is no different. Over the last few months interest in deep-UV LEDs has rocketed, due to its capability to disinfect and sanitise areas and combat Covid-19. We shall consider a roadmap for this device, along with technologies for boosting its output.
We shall also look at microLEDs, a display with many wonderful attributes, identifying processes for handling the mass transfer of tiny emitters that hold the key to commercialisation of this technology.
We shall also discuss electrification of transportation, underpinned by wide bandgap power electronics and supported by blue lasers that are ideal for processing copper.
Additional areas we will cover include the development of GaN ICs, to improve the reach of power electronics; the great strides that have been made with gallium oxide; and a look at new materials, such as cubic GaN and AlScN.
Having attracted 1500 delegates over the last 2 online summits, the 3rd event promises to be even bigger and better – with 3 interactive sessions over 1 day and will once again prove to be a key event across the semiconductor and photonic integrated circuits calendar.
So make sure you sign up today and discover the latest cutting edge developments across the compound semiconductor and integrated photonics value chain.
REGISTER FOR FREE