With all of us opto folks going gaga over the $10+ billion LED market, stop and consider that the LED driver IC market is a sweet $2 billion, and growing at 12% compounded annually. And I'm going to say it: drivers is a photonics market too.
OK, I said it. Electronics is photonics too. I'm stretching things a bit, since the suppliers of LED driver ICs are companies like Texas Instruments, Maxim, Analog Devices, and Macroblock who don't know or care about photons. They do know a lot about hand-crafted analog circuit designs and specialty fab processes that enable circuits tolerant to high-voltages--the kind that drive long LED strings in display backlights.
But good LED design optimizes the entire circuit for efficiency, reliability, LED uniformity, and many other specs. We call the circuit--minus the LEDs themselves--the driver. It may include zero, one, or multiple ICs for the purpose.
Opto people, like myself, tend to think that there is nothing interesting in the system apart from the quantum mechanics of electron-hole recombination and fancy MOCVD epitaxial growth. But when product designers take the electronics for granted, system performance is notoriously terrible, and that's bad for the whole LED industry. Likewise, electronics designers tend to take the LED for granted, but LEDs are requiring surprisingly novel and sophisticated circuits. The only way to achieve widespread LED lighting is if electronics designers innovate enough to meet cost and performance goals. Fortunately, there are those out there who can. Look for example at companies like Exclara, iWatt, Luxera, and Lynk Labs, to name a few.
The boundary between electronics and photonics is also fuzzy for lightwave transceivers. The laser and detector in a transceiver are typically very cheap, so much of the value is in the electronics: driver and receiver, clock recovery, and so on inside the module, not to mention all the higher level routing and control elsewhere on the board.
In imaging, it is even more dramatic. The detector array is sophisticated, but the image processing electronics takes it further, correcting optical limitations and even adjusting focus after the fact. The point is not that the electronics helps the optics, but that optical science actually resides in the electronics, often on the same chip as the sensor array.
I'll get back to the LED driver market again, but for now, remember: Electronics can be photonics too.