Optical time domain reflectometer in a small form factor package
A system for creating an optical time domain reflectometer (OTDR) in a small package is described. This system allows the implementation of multiple channels of OTDR in package of similar size to existing fiber optic transceivers.
1. An optical time domain reflectometer (OTDR) device, comprising:
a connector guide configured to mate to an attachable fiber optic connector;
a beam splitter disposed within the connector guide;
a lens seal coupled to a bottom portion of the connector guide;
a collimating lens in alignment with the beam splitter and sealed to a bottom portion of the lens seal to prevent external contamination;
a transparent carrier coupled to a bottom portion of the collimating lens, wherein the transparent carrier has electrical pathways;
an optical transmitter and optical receiver in alignment with the collimating lens and mounted to an underside of the transparent carrier and connected to the electrical pathways; and
a transmitting and receiving circuit mounted to the underside of the transparent carrier and connected to the electrical pathways, a transmitter of the transmitting and receiving circuit configured to send a signal to the optical transmitter to cause the optical transmitter to send a pulse of light into an optical fiber of the attachable fiber optic connector, and a receiver of the transmitting and receiving circuit configured to receive a signal from the optical receiver, from a received pulse of light from the optical fiber of the attachable fiber optic connector;
wherein a time domain reflectometry measurement is determined from a time difference between a sent and received signal.
2. The device of claim 1 , wherein the time domain reflectometry measurement is for a plurality of fibers in the attachable fiber optic connector.
3. The device of claim 1 , wherein the transmitting and receiving circuit comprises a timing control ASIC and a transceiver ASIC.
4. The device of claim 1 , wherein the beam splitter is configured with at least one of a first partially reflective surface of approximately 45 degrees and a second surface that is approximately 100% reflective.
5. The device of claim 1 , wherein the transmitting and receiving circuit is flip-chip bonded to the transparent carrier.
6. The device of claim 1 , wherein the transparent carrier and lens seal are flip-chip bonded to each other.
7. The device of claim 1 , wherein the optical receiver comprises a OTDR receiver and an additional optical receiver.
8. The device of claim 1 , wherein an overall height of the device is less than 10 mm.
9. The device of claim 1 , wherein the beam splitter, lens seal, collimating lens, transparent carrier, and at least one of the optical transmitter and optical receiver have a matching coefficient of thermal expansion of less than +/−5 ppm/C. deg.
10. The device of claim 1 , wherein at least one of the optical transmitter, the optical receiver and the transmitting and receiving circuit is formed on the transparent carrier.
11. The device of claim 1 , wherein the optical receiver is a PIN diode, and the optical transmitter is at least one of a diode laser, diode LED and modulated laser.
12. device of claim 1 , wherein the transparent carrier is mounted to a substrate having a plurality of electrical wiring, and a portion of the transparent carrier's electrical pathways are in communication with the substrate's electrical wiring.
13. The device of claim 1 , wherein the transmitting and receiving circuit further comprises an OTDR timing circuit.
14. The device of claim 11 , wherein the optical receiver and optical transmitter are aligned to a desired position on the transparent carrier within a precision of less than 3 microns.
15. The device of claim 12 , wherein the substrate is a ceramic carrier substrate.
16. The device of claim 12 , wherein the transparent carrier is flip-chip bonded to the substrate.
17. The device of claim 13 , wherein at least one of the transmitting and receiving circuit and the OTDR timing circuit is an application specific integrated circuit (ASIC).
18. The device of claim 13 , wherein the OTDR timing circuit comprises a clock circuit, a pattern generator and delay circuit, sampling receiver circuit, and a optical transmitter compatible signal driver.
19. The device of claim 18 , wherein the sampling receiver circuit is configured to take two samples, one sample accounting for system noise.
20. A method of performing optical time domain reflectometry, comprising:
generating a clocking signal via a first integrated circuit bonded to a transparent substrate;
generating a pulse pattern via a second integrated circuit bonded to the transparent substrate;
transmitting the pulse pattern to a driver bonded to the transparent substrate;
exciting an optical transmitter bonded to the transparent substrate with the pulse pattern from the driver, to emit light pulses into a bi-directional coupler that couples light into a first fiber and couples light from the first fiber into a second fiber;
detecting via an optical receiver bonded to the transparent substrate, a received light from the second fiber; and
sampling the received light and measuring a time difference, via a timing circuit bonded to the transparent substrate, between a sent and received light, to determine a time domain reflectometry measurement.
21. The method of claim 20 , wherein the first integrated circuit, second integrated circuit, driver, optical transmitter, optical receiver, and timing circuit are bonded to the transparent substrate via a flip-chip bonding process.
22. The method of claim 20 , wherein the sampling is performed at least two times, wherein one sample determines a baseline measurement of system noise.