Multiple reflectivity band reflector for laser wavelength monitoring

A method for monitoring a laser system comprising the steps of:

• pumping an active region located in a laser cavity of a laser, at least a portion of the laser cavity defined by a first mirror and an exit mirror, until laser light is emitted;
• coupling a multiple reflectivity band reflector (MRBR) to at least a portion of the emitted laser light, the MRBR having at least first and second wavelength bands with reflectivity above a particular reflectivity separated by at least a third wavelength band having reflectivity below the particular reflectivity, such that the MRBR transmits filtered laser light;
• coupling at least a portion of the filtered laser light to a first photodiode such that an output is produced based on the amount and wavelength of light received by the first photodiode;
• and
• adjusting the emitted wavelength of the laser toward a desired wavelength in one of the at least first, second, and third wavelength bands based at least in part on the output of the first photodiode.

A computer program, stored on a tangible storage medium, for monitoring a laser, the program comprising executable instructions that cause a processor to

• send a signal resulting in pumping an active region located in a laser cavity of a laser, at least a portion of the laser cavity defined by a first mirror and an exit mirror, until laser light is emitted;
• store an output of a first photodiode coupled to at least a portion of filtered laser light transmitted by an MRBR that is coupled to at least a portion of the laser light;
• and
• send a signal resulting in adjusting the emitted wavelength of the laser toward a desired wavelength based at least in part on the stored output of the first photodiode.

A multiple reflectivity band reflector, comprising a plurality of layers of material arranged in parallel such that the reflector has:

• a first wavelength band with reflectivity above a lasing threshold reflectivity;
• a second wavelength band with reflectivity above the lasing threshold reflectivity;
• and
• a third wavelength band including wavelengths between the first and second wavelength bands having reflectivity below the lasing threshold reflectivity.

A laser apparatus, comprising:

• a laser comprising:
• a first mirror;
• a second mirror comprising a multiple reflectivity band reflector (MRBR) having at least first and second wavelength bands with reflectivity above a lasing threshold reflectivity separated by a third wavelength band having reflectivity below the lasing threshold reflectivity;
• at least a portion of a laser cavity defined by the first mirror and the MRBR;
• and
• an active region located within the laser cavity, the active region containing a material that is capable of stimulated emission at one or more wavelengths in the first and second wavelength bands.

A monitored laser system, comprising:

• a laser comprising
• a first mirror,
• an exit mirror, at least a portion of a laser cavity defined by the first mirror and the exit mirror;
• and
• an active region located in the laser cavity, the active region containing a material that is capable of stimulated emission at one or more wavelengths of laser light within a tuning range of the laser;
• a multiple reflectivity band reflector (MRBR) coupled to at least a portion of laser light emitted from the laser and transmitting filtered laser light, the MRBR comprising a plurality of layers of material arranged in parallel such that the reflector has a plurality of reflectivity peaks within the tuning range, each reflectivity peak separated from neighboring reflectivity peak by a reflectivity trough having a trough minimum, said reflectivity peaks characterized by a peak profile and said trough minima between said reflectivity peaks characterized by a trough profile, wherein at least one of said peak profile and said trough profile has a substantially non-constant relationship of wavelength to reflectivity;
• a first photodiode coupled to at least a portion of the filtered laser light and producing an output based on the amount of light received;
• and
• means for adjusting the emitted wavelength of the laser toward a desired wavelength within the tuning range based at least in part on the output of the first photodiode.

A monitored laser system, comprising:

• a laser comprising
• a first mirror,
• an exit mirror,
• at least a portion of a laser cavity defined by the first mirror and the exit mirror;
• and
• an active region located in the laser cavity, the active region containing a material that is capable of stimulated emission at one or more wavelengths such that laser light is emitted from the laser;
• a multiple reflectivity band reflector (MRBR) coupled to at least a portion of the emitted laser light and transmitting filtered laser light, the MRBR having at least first and second wavelength bands with reflectivity above a particular reflectivity separated by at least a third wavelength band having reflectivity below the particular reflectivity;
• a first photodiode coupled to at least a portion of the filtered laser light and producing an output based on the amount and wavelength of light received;
• and
• a non-section-112(6) means for adjusting the emitted wavelength of the laser toward a particular wavelength in one of the at least first, second, and third wavelength bands based at least in part on the output of the first photodiode.