Patent ID: 6829262
Filing Date: 2004-12-07
Classification: H01S

Abstract:
A process for evaluating an aging property of a distributed Bragg reflector (DBR) laser, the DBR laser comprising a laser cavity bounded on a first end by a reflective surface and a tunable reflector portion located adjacent to a second, opposing end of the laser cavity, said tunable reflector portion including a Bragg grating that functions as a distributed reflector, the tuning supplied by a tuning current applied across said tunable reflector, the process comprising the steps of:a) providing an initial relationship &lgr;(I) between the laser output wavelength &lgr;i and tuning current I as applied to the tunable reflector portion; b) placing the laser cavity in a non-lasing state; c) illuminating the Bragg grating by an external light source; d) applying a first tuning current to said tunable reflector portion and measuring a reflected spectrum and determining a Bragg peak wavelength &lgr;B,i for said tuning current I; e) repeating step d) for a plurality of tuning currents to determine a Bragg peak wavelength for each tuning current, defined as a pre-aging tuning current; f) turning on and aging said laser cavity, then returning said laser cavity to the non-lasing state; g) repeating step d) for the plurality of tuning currents to determine a post-aging Bragg peak wavelength &lgr;B,n for each tuning current I; h) calculating, for each Bragg peak wavelength &lgr;B, a functional relationship between a pre-aging tuning current Ii and a post-aging tuning current In, where Inâˆ’Ii=f(&lgr;B,n(Ii)âˆ’&lgr;B,i(Ii)); i) selecting a laser output wavelength &lgr;i; j) selecting a pre-aging tuning current I for producing the selected output laser wavelength &lgr;i, using the relationship provided in step a); and k) applying a post-aging tuning current In to said tunable reflector portion associated with the pre-aging tuning current Iiselected in step j), the post-aging tuning current selected using the functional relationship calculated in step h).