Reflector with tunable spectral reflectance

An optoelectronic device for enabling more flexible and precise control of spectral properties of laser radiation, the device comprising:

• a gain medium and configured to amplify the laser radiation within a gain band between a maximal wavelength (λmax) and a minimal wavelength (λmin);
• a laser cavity containing the gain medium and comprising:
• a first reflector disposed on a first side of the gain medium;
• and
• a second reflector disposed on a second side of the gain medium, opposite the first side, the second reflector comprising:
• a first Mach-Zehnder interferometer (MZI), comprising first and second legs having a tunable first optical pathlength difference (OPD) greater than 2×λmax;
• a second MZI, coupled in series with the first MZI and comprising third and fourth legs having a tunable second OPD less than 2×λmin;
• and
• an optical coupler configured to direct an input optical signal in the selected wavelength range into the first and second MZIs and to output a reflected optical signal from the first and second MZIs;
• and
• a controller configured to adjust the first and second OPDs to adjust the spectral properties of the laser radiation by controlling a spectral reflectance of the reflected output optical signal from the second reflector relative to the input optical signal.

A method for flexible and precise control of spectral reflectance in a selected wavelength range having a maximal wavelength (λmax) and a minimal wavelength (λmin), the method comprising:

• coupling a first Mach-Zehnder interferometer (MZI), comprising first and second legs and having a tunable first optical pathlength difference (OPD) between the first and second legs that is greater than 2×λmax, in series with a second MZI, comprising third and fourth legs having a tunable second OPD less than 2×λmin;
• directing an input optical signal in the selected wavelength range into the first and second MZIs;
• outputting a reflected optical signal from the first and second MZIs;
• and
• adjusting the first and second OPDs to control the spectral reflectance of the reflected optical signal.