Vertical cavity surface emitting lasers with consistent slope efficiencies

A method for fabricating surface emitting lasers having substantially similar slopes from a plurality of wafers, the method comprising the steps of:

• fabricating a plurality of surface emitting lasers on a wafer;
• testing a sample of the lasers to determine slope efficiency distribution of the lasers on the wafer;
• and
• changing transmission of the lasers on the wafer by an amount calculated to tune the slope efficiency distribution of the lasers to within a predetermined range.

A surface emitting laser comprising:

• a substrate;
• a first mirror disposed on the substrate;
• an optical cavity adjacent the first mirror;
• a second mirror having a top facet reflectivity disposed adjacent the optical cavity opposite the first mirror;
• and
• a tuning layer for predictably changing the top facet reflectivity by an amount based on values predetermined to adjust slope of the laser to within a desired range.

A plurality of surface emitting lasers having substantially similar slopes fabricated from first and second wafers, each of the lasers comprising:

• a substrate;
• a first mirror disposed on the substrate;
• an optical cavity adjacent the first mirror;
• a second mirror having a top facet reflectivity disposed adjacent the optical cavity opposite the first mirror;
• and
• wherein the lasers on the first wafer further comprise a first tuning layer having a first tuning layer thickness over the second mirror, and the lasers on the second wafer have a second tuning layer having a second tuning layer thickness over the second mirror, and wherein the first tuning layer thickness substantially differs from the second tuning layer thickness.

An optical subassembly comprising:

• an electrical package containing a VCSEL with variable tuning layer and a photodetector for monitoring power of the VCSEL;
• a housing attached to the electrical package, the housing including a ball lens aligned in an optical path carrying light from the VCSEL into an optical fiber, and a ferule for aligning the optical fiber in the optical path;
• and
• wherein the VCSEL is tuned to enable the optical subassembly to perform within a specification, and wherein the VCSEL comprises:
• a substrate;
• a first mirror disposed on the substrate;
• an optical cavity adjacent the first mirror;
• a second mirror having a top facet reflectivity disposed adjacent the optical cavity opposite the first mirror;
• and
• a tuning layer for predictably changing the top facet reflectivity by an amount based on values predetermined to adjust slope of the laser to within a desired range.

An optical transceiver comprising:

• a transmitter portion including:
• an optical subassembly containing a VCSEL with a variable tuning layer;
• an AC laser driver coupled to the optical subassembly for applying an AC modulation signal to the VCSEL;
• a DC bias circuit for applying a bias signal to the VCSEL;
• and
• wherein the VCSEL is tuned to enable the optical transceiver perform within a specification, and wherein the VCSEL comprises:
• a substrate;
• a first mirror disposed on the substrate;
• an optical cavity adjacent the first mirror;
• a second mirror having a top facet reflectivity disposed adjacent the optical cavity opposite the first mirror;
• and
• a tuning layer for predictably changing the top facet reflectivity by an amount based on values predetermined to adjust slope of the laser to within a desired range.