VCSEL with monitor emission through high reflectivity mirror
View Patent ↗A bottom emitting VCSEL where the light emitted can be monitored without obstruction. No additional mountings are required, such as a header, to monitor output, which mountings are necessary in prior art arrangements.
1. A bottom-emitting vertical cavity surface emitting laser, comprising:
a substrate permitting the passage of light therethrough.
a laser stack consisting essentially of a high reflectivity mirror, a low reflectivity mirror; and an active light-amplifying region located between said high and low reflectivity mirrors, said laser stack being provided on said substrate with said low reflectivity mirror adjacent said substrate;
a light output port located in said substrate adjacent said low reflectivity mirror for transmitting light emitted by said active light-amplifying region and constituting an output of said laser; and
an ohmic contact provided on said high reflectivity mirror, said ohmic contact being photon transparent for transmitting some of said light emitted by said light-amplifying region that passes through said high reflectivity mirror for monitoring with an external photodetector.
2. A surface emitting cavity laser as claimed in claim 1 , wherein said ohmic contact is made of a photon transparent material.
3. A surface emitting cavity laser as claimed in claim 2 , wherein said photon transparent material comprises Indium Tin Oxide.
4. A surface emitting cavity laser as claimed in claim 1 , wherein said ohmic contact contains an aperture to pass light there through.
5. A surface emitting cavity laser as claimed in claim 1 , wherein said ohmic contact has a thickness between 1 and 100 nm.
6. A surface emitting cavity laser as claimed in claim 1 , wherein, said output port is provided by a hole in said substrate.
7. A surface emitting cavity laser as claimed in claim 6 , wherein said ohmic contact is made of a photon transparent material.
8. A surface emitting cavity laser as claimed in claim 7 , wherein said photon transparent material comprises Indium Tin Oxide.