Screw the hype – technically speaking
Investors demonstrate unbecoming schoolboyish excitement when it comes to photonics. They fall over themselves to declare it the next gravy train, the modality that will finally deliver quantum advantage (making them billions, of course), the shiny horse to back (beware, read my earlier article on which horse are you backing). And, true to the zeitgeist, they bank on the buzz and forget the depth – forget the substance. It is typical of this day and age: pour billions into the headline, ignore the footnotes and hope the cash cow survives the milking.
But beneath the bonnet of this so‑called photonic revolution lie the quiet, unglamorous components that actually make the train move. And if even one of these humble nuts and bolts fails, the entire locomotive stalls. Yet because they lack hype, almost no one peers beneath the bonnet. Big sigh. Chase the bucks, forget the mechanics.
So let me start taking them apart, one by one. Starting with tunable lasers.
Image: A typical laser diode. When mounted with external optics, these lasers can be tuned mainly in the red and near-infrared. Public domain image from Jet Propulsion Lab.
Tunable Lasers: The Pen‑Drive‑Sized Workhorses of Photonics
These small, pen‑drive‑sized beauties are not optional accessories; they are the beating heart of photonic quantum systems. Without them, nothing works. No qubit initialisation, no coherent control, no entangling operations, no readout.
Photonics may be the gravy train, but tunable lasers are the rails. Remove the rails, and the train does not merely slow – it never leaves the station. But do these hungry, superkeen investors know this??????
A photonic qubit is nothing more than exquisitely controlled light. And exquisitely controlled light does not appear by magic. It requires:
- ultra‑narrow linewidth sources
- precise wavelength tuning
- low phase noise
- long‑term frequency stability
- clean spectral purity
These are not marketing adjectives. They are hard physical constraints. If your laser drifts by even a few kilohertz, your qubit drifts with it. If your phase noise spikes, your gate fidelity collapses. If your spectral purity degrades, your entanglement vanishes.
This is why tunable lasers matter. They are the quiet custodians of coherence that few bother to think about when chasing the photonics dream.
Why Investors Should Care . But Don’t
Most investors have never heard of tunable lasers. They know the word photonics, but not the machinery that makes photonics possible. They talk about scaling, but not about the fact that scaling requires dozens – eventually thousands – of stable, narrow‑linewidth lasers operating in perfect synchrony.
They talk about billion‑dollar valuations, but not about the supply chain fragility of these components. They talk about quantum advantage, but not about the fact that a single unstable laser can destroy an entire computation. That this winds me up BIG TIME.
And this is the uncomfortable truth: The photonics gravy train depends on components no one is paying attention to.
The Technical Reality Under the Hype
A tunable laser is not just a light source. It is a precision instrument that must satisfy quantum‑grade requirements:
- Linewidth: Sub‑100 kHz, ideally sub‑10 kHz. Anything broader introduces decoherence.
- Tunability: Wide spectral range to hit atomic transitions, nonlinear crystals, and integrated photonic resonances.
- Phase Noise: Must be suppressed to prevent qubit phase errors.
- Frequency Stability: Long‑term drift must be negligible; otherwise, gates become inconsistent.
- Spectral Purity: Side modes and spurious peaks destroy interference visibility.
These are the nuts and bolts. They are not glamorous, but they are essential.
And yet, because they do not come with glossy investor decks or breathless headlines, they remain invisible. The industry pours billions into photonics while ignoring the very components that determine whether photonics will succeed.
Why I’m Writing This
Because someone needs to say it. Because the quantum industry cannot afford another hype cycle built on selective ignorance. Because investors deserve to know what they are actually backing. And because photonics might indeed be the future – but only if we stop pretending that the future is built from buzzwords rather than hardware.
So yes, photonics may be the gravy train. But tunable lasers – these humble, pen‑drive‑sized workhorses – are the nuts and bolts holding the entire train together.
And if we don’t pay attention to them, the train will not move. WAKE UP.
