Facet coatings for nonhermetically packaged lasers

Nonhermetic packaging is one avenue of reducing the module cost of optical devices; however, this requires the coatings applied to the facets of lasers and modulators to be highly stable and impervious to the effects of high humidity under high temperature/high power operating conditions. We have developed two types of facet coatings for nonhermetic applications. One involves electron cyclotron resonance plasma enhanced chemical vapor deposition (ECR-PECVD) of a SiNx cap layer and the other utilizes ion beam deposition (IBD) of a Ta2O5 cap layer, both on top of a two-layer SiO2/a-Si high-reflectance (HR) coating deposited on the facets of Fabry-Perot (F-P) ridge waveguide (RWG) lasers operating at 1310 nm. The lasers were aged under 85 deg. C/85% relative humidity (RH) conditions and ex situ tested using drive currents of 10-20 mA (subthreshold) and 80-120 mA operating currents (Iop). The output power-current-voltage (L-I-V) tests were conducted at room temperature and at various time intervals up to 5000 h. For comparison, tests were also done on devices aged in a dry oven