Stray light insensitive detector system and amplifier
View Patent ↗A detector system for a fiber optic component is insensitive to stray light. Specifically, the invention comprises a detector chip, which converts received light into an electric signal. A baffle substrate is positioned over the detector chip. This baffle substrate has a transmission port through which an optical signal is transmitted to the detector chip. As a result, light that is not directed to be transmitted through the port is blocked by the baffle substrate. In this way, it rejects stray light that may be present in the hermetic package. A detector substrate is provided on which the detector chip is mounted. This detector substrate preferably comprises electrical traces to which the detector chip is electrically connected. The detector substrate can further comprise bond pads for wire bonding to make electrical connections to the electrical traces.
1. A system comprising:
an optical bench on which an optical system is installed, the optical system include a stray light insensitive detector system comprising:
a detector chip which converts received light into an electrical signal;
a detector substrate on which the detector chip is mounted;
a baffle substrate positioned over the detector chip, the baffle substrate being non-transmissive and having a transmission port through which an optical signal is transmitted to the detector chip, the transmission port comprising a hole through the baffle substrate and extending parallel to a top surface of the optical bench to enable the detector chip to detect optical signals in the optical system; and
a spacer between the detector substrate and the baffle substrate to space the baffle substrate away from the detector chip, the spacer being annular shaped with the detector chip being installed within a center region of the spacer on the detector substrate, the spacer being installed on the optical bench to project vertically from the bench with an axis of the center region extending parallel to the surface of the bench;
wherein the optical signal propagates in free space above the optical bench before being directly received into the transmission port and propagating in free space through the port to the detector chip.
2. A system as claimed in claim 1 , wherein the detector substrate comprises electrical traces to which the detector chip is electrically connected.
3. A system as claimed in claim 2 , wherein the detector substrate comprises bond pads for wire bonding to make electrical connection to the electrical traces.
4. A system as claimed in claim 1 , wherein the baffle substrate comprises a light blocking coating on at least one side of the substrate and outside of the transmission port.
5. A system as claimed in claim 1 , wherein the baffle substrate comprises a light blocking coating on a front side and a back side of the baffle substrate and outside of the transmission port.
6. A system as claimed in claim 1 , wherein the baffle substrate is absorbing to at wavelength of the stray light.
7. A system as claimed in claim 1 , wherein the baffle substrate is coated to be reflective at a wavelength of the stray light.
8. A system as claimed in claim 1 , further comprising a blocking cap substrate positioned over the baffle substrate to block stray light.