c either a local power supply rated at 100 mw or less or a photo generated power as explained above with reference to fig3 can be used to power the microprocessor 502 and the mems driver 504 turning to fig6 with further reference to fig3 a method 600 of thermal stabilization of the awg 11 includes a step 602 of generating powering light at a powering wavelength different from wavelengths of the optical beam 204 in a step 604 the powering light is added to the optical beam 204 for example by means of a wavelength division multiplexor steps 602 and 604 can be performed at a remote location from which the optical beam travels e g inside an optical fiber towards the wavelength selective device 300 in a step 606 the portion 310 of the optical beam 204 containing the powering light is split from the optical beam 204 using the splitter 306 and directed towards the photovoltaic cell 312 for conversion into electric power in a step 607 in a step 608 the optical beam 204 is coupled to the input slab 214 of the awg 211 this is done by first coupling the optical beam 204 to the tiltable mems mirror 206 for reflecting the optical beam 204 and second directing the reflected optical beam 204 to the lens 208 or another suitable focusing element for focusing the reflected optical beam 204 into the.