When an OEwaves customer referred to our lasers as having “Ridiculously Narrow Linewidth”, we took that as an expression of their amazement at how a semiconductor laser in a small, cellphone sized package that includes the drive electronics, can deliver low noise at sub-Hz level. Of course, what makes this performance possible is our patented approach of self-injection locking (SIL) of the diode to our unique crystalline whispering gallery mode resonators. This results in an “extended cavity” configuration with the “cavity” sporting a quality factor (Q) in excess of 1 billion, up to 10 billion. The SIL architecture featuring a simple way of locking with no required electronics well represents our philosophy that carefully designed simplicity gives the best results. We understand Ockham discovered this philosophy a long time ago and we thank him for his wisdom.
But there are other desirable features of our patented approach: we can generate such a low noise performance for any available diode within the UV to IR range; and we can actuate a PZT placed on the resonator (also our own patented design) to modulate the laser extremely linearly to a (shall I say, ridiculously?) low RAM level below 80 dB! In this way PDH locking the output of the laser to a reference cavity or an atomic transition becomes a cinch. But this easy (simple again?) approach also has the desirable outcome of providing a system that is amazingly robust.
So, when a customer called us to report that their laser locked with our PZT modulator to a reference cavity did not budge even as he repeatedly banged on the optical table, we were not surprised. We were smiling, though, when he also said “This laser is nice!”. So, here you have it: Ridiculous but Nice. Leave it to the scientists, engineers, and technicians at OEwaves to produce a laser making mixed metaphors look good!