Miniaturization And High Integration Become A Key Proposition in Laser Development

In order to realize the goal of next-generation coherent pluggable devices, next-generation tunable lasers must reach a whole new level of optoelectronic integration.
It is worth noting that miniaturization and integration of lasers is not just a size challenge, but more importantly, how to improve the power efficiency of these lasers. Here are some of the benefits that small lasers offer in terms of improved energy efficiency:
First, small lasers have lower operating voltage and current requirements. This is because highly integrated laser designs often utilize advanced processes and materials that allow for much lower threshold voltages and currents than traditional large lasers.
Second, the compact design contributes to improved heat dissipation. In small lasers, the distance that light travels within the laser chip is much shorter, which helps to minimize light loss and heat dissipation problems.
In addition, highly integrated lasers can reduce coupling losses. In photonics, the coupling between free-space optics and the chip has always been a technical challenge. By integrating multiple functions on a single chip, the new lasers are able to avoid this coupling and its associated losses.
Photonic integration is essential to reduce size and power consumption. As more and more components are integrated onto a single chip, losses are gradually reduced and the efficiency of the optical transceiver increases accordingly.
Successes and Challenges in Laser Integration Technology
Tunable laser integration technology has advanced significantly over the past decade, largely meeting the market's pressing need for smaller size and higher integration.
In 2011, tunable lasers followed the guidelines of the Multi-Source Agreement (MSA) for Integration of Tunable Laser Assemblies (ITLA), initially demonstrating their integration potential.
In 2015, tunable lasers were further miniaturized and brought to market in the form of compact micro-ITLAs that are only 22% of the size of the original ITLA package, significantly reducing device size.
In 2019, the size is further reduced with the advent of the nano ITLA, a module that is only 39% of the micro ITLA, reflecting the continuity and constant progress in technology development.

Figure 1: Evolution of coherent optics tunable laser shape factor 2011-2021
Despite these impressive advances, laser integration technology still faces further integration challenges, especially in the 100G ZR coherent access space, where there is a growing demand for QSFP28 pluggable devices.
QSFP28 pluggable modules offer lower power consumption and a smaller footprint than QSFP-DD modules, so they should not use the same lasers as QSFP-DD modules. What they need - dedicated laser solutions with a smaller footprint and lower power consumption.

Figure 2: Comparison of QSFP-DD and QSFP-28 form factors for 100G applications
In order to achieve this goal, the development of monolithic lasers becomes critical.
Ideally, such a laser would be able to integrate all key laser functions, including gain, laser cavity, and wavelength locker, on the same chip, resulting in a significant increase in integration, a reduction in size, and a reduction in power consumption. The realization of this technology will lay a solid foundation for the development of next-generation optical communication devices.
Promoting further size reduction of tunable lasers
In the future, in order to further reduce the size of tunable lasers, it will be necessary to realize a high degree of integration of their internal components.
For example, each tunable laser relies on a wavelength locker assembly to ensure the stability of the laser output under various environmental conditions such as temperature.
Integrating the wavelength locker assembly directly onto the laser chip, rather than through external connections, significantly reduces the space footprint and energy consumption of the laser package.
EFFECT Photonics, the Dutch leader in optical integration technology, has come up with an innovative solution: they have developed a single-chip solution compatible with a wide range of tunable lasers, which integrates all functions, including the wavelength locker, on a single chip. This configuration is ideal for reducing power consumption and driving mass production.
By integrating all tunable laser functions on a single chip, EFFECT Photonics has successfully developed the new pico-ITLA (pITLA) module, which will be the smallest ITLA for coherent applications worldwide.
The pITLA is a forward-looking product for tunable laser integration that includes all laser functions in a package that is only 20% of the size of a nanoITLA module. It is only 20% of the size of a nanoITLA module. As shown in Figure 6, the pITLA appears extremely small even when compared to a standard matchstick.

Figure 3: Evolution of coherent optics ITLA module form factor and size reduction, 2011-2023

The impact of miniaturized integrated lasers goes far beyond the size advantage; it is equally critical to improving power efficiency. More compact laser designs can often operate at lower voltages and currents, which helps improve thermal performance and minimize coupling losses.
And photonic integration is a key factor in achieving these performance gains - by combining multiple functions on a single chip, efficiency can be maximized.
Compact and energy-efficient QSFP28-sized coherent pluggable devices and their accompanying miniaturized tunable lasers are in high demand as we advance the use of 100G coherent technology in access networks. pITLA modules from EFFECT Photonics are an important step in this integration and miniaturization process.
At only 20% of the size of a nanoITLA module, the pITLA not only meets the industry's expectation for smaller size, but also demonstrates the continued pursuit and drive to realize compact, efficient and scalable tunable lasers at the edge of optical networks.