Though optical parts are still 'big' and nobody seems to know how to make small IC's - 20 years ago I worked in networking and they were trying to make optical

Though optical parts are still 'big' and nobody seems to know how to make small IC's - 20 years ago I worked in networking and they were trying to make optical switches with mirrors! At the long haul level, they use a transport layer tech called SONET. Rather than demuxing the optical signal into bits, then back into optical and out another pipe, they wanted to switch using fancy mirrors. Frankly, I'm not sure of the advantage. Maybe some performance? Security? I'm doubtful though.