Experimental work on the quantum effect in photonics goes back to 1976 at AT&T-Bell Labs which resulted in the formation of a set of photodiodes. Into the 1980s, there was optimism that such gear could be used in a couple of large applications. Fast forward to today and the hyperbole surrounding quantum is at an all-time high. Large optical organizations catering to the needs of suppliers cannot afford to ignore the vast amounts of capital being thrown at quantum, despite the overwhelming challenges continuing to get in the way. At least the Rump Session at OFC’22 will provide equal time to the naysayers, who have difficulty seeing it move much beyond fundamental science. Unsurprisingly, the co-captains of the two teams are divided on pragmatic grounds with the pro side represented by a couple of prominent laboratory individuals. Still, there are expected to be several exceptions, especially in the much longer term, in which quantum may go further away from applied research in the optical realm.
Certainly, it is not inconceivable that if Peter Winzer were still at Nokia Bell Labs, he may have wound up on the other team, despite the relatively conservative movement by the actual vendor, Nokia Networks, on optical development in remaining at 400G. For example, we recall him at ECOC’16 being highly exuberant in his projections for particular amounts of petabit capacity that he thought would be necessary in future years in networks.
Additionally, co-captain, Andrew Lord acknowledged at least indirectly to us at the previous OFC that despite his very positive remarks, the network planners would play the instrumental role at BT in deciding on the merits of Infinera’s XR Optics, a concept clearly with a much greater chance of success as compared with quantum. The situation is comparable to the practical nature of his opponent, Verizon’s Glenn Wellbrock, who remains careful when it comes to disaggregation/openness, and likely prefers the optical system houses to concentrate their efforts on getting costs down on mature devices, particularly in supporting 5G wireless infrastructure.
The fourth co-captain, Mekena Metcalf, with Lawrence Berkeley National Laboratory, will be representing the pro-quantum position, and based on her background, we anticipate that she will be concentrating her attention on the broader quantum computing arena. Nevertheless, unlike in a market situation, there is no fixed timetable for demonstrating results when it comes to working at a government-funded lab.
In looking generally at the optical space over the last 40 years, change has not tended to occur in revolutionary ways. As fibeReality reminded everyone at ECOC’21, any kind of paradigm shifts are accompanied by relatively rare aberrations in the marketplace, such as Sprint enabling the existence of Ciena in the 1990s because of the small number of fibers in its cables, along with the desire of the former to prevent a re-engineering of its network in moving to 10G. Even then, this type of change is not as radical as moving to quantum as DWDM followed CWDM, PAM4 (although its necessity is considered somewhat controversial) took advantage of a modulation technique, which was widely implemented across industries; the use of coherent technology for higher end optics transmission was well-established many decades ago in the microwave sector; and the comparatively quiet shift to the O-band for 5G purposes was, of course, an obviously incremental step as well.
Quantum calls for much grander ambitions in the excitation of atoms to a higher energy state. That kind of progress will usually require a much bigger leap to achieve actual productization. It is also hardly out of the question that some otherwise intelligent network planners at incumbent operators may have problems fully grasping the complexities involved with quantum.
To be fair, there is a whole slew of potentially vast applications for the quantum properties of light. Random number generators, etc. have been productized. Conversely, while quantum theory provides the most accurate set of tools with some calculations going to 12 to 15 digits, mass production leaves a lot to be desired.
Regarding another exception, one type of product to keep an eye on is quantum dot lasers with their ability to generate combs for higher-wavelength count, data communications applications. Although reliability has been a difficulty in the past, it has been getting solved with improved material systems.
Concerning other apps that may appear to be more real, there are optical qubits, which are early in the R&D process. To the extent that they are required, if at all, involves the secure exchange of keys. Unfortunately, it seems that newcomers targeting this app have an extremely short window of opportunity.
Moreover, both quantum clocks and sensors are hardly around the corner. However, perhaps both have the advantageous peculiarity of demonstrating the exception to the rule in being more evolutionary in nature in terms of equipment requirements and manufacturing technology.