Distributed optical combining: OBI free, power free
Implementing a laser into a system that uses a remote powered combiner or an aggregating combiner (AC) with one or more in-range contributing combiners may provide power to the downstream contributing combiners (CC). The power may be provided on the same fiber that downstream signals and the upstream signals traverse.
1. A contributing optical splitter/combiner configured to function passively without electrical power, the contributing optical splitter/combiner connected via a fiber to an aggregating optical splitter/combiner with at least one output port located upstream from the contributing optical splitter/combiner, the contributing optical splitter/combiner comprising:
one or more detectors for detecting reverse path optical signals received from one or more optical network units (ONU) and configured for detecting forward path optical signals received from the upstream aggregating optical splitter/combiner
at least one additional detector for detecting a light injected in a forward path by a pump laser by the upstream aggregating optical splitter/combiner,
a powering circuit configured to use the forward path light from the upstream aggregating optical splitter/combiner's pump laser to provide electrical power to the contributing optical splitter/combiner, powering at least one of downstream circuitry or upstream circuitry in the contributing optical splitter/combiner for processing the respective reverse path optical signals and forward path optical signals.
2. The contributing optical splitter/combiner of claim 1 , wherein the contributing optical splitter/combiner is without an electrical power connection.
3. The contributing optical splitter/combiner of claim 1 , wherein the contributing optical splitter/combiner and the aggregating optical splitter/combiner are located within a close enough proximity to each other that the fiber connecting the combiners is of a length that the light injected in to the fiber from the pump laser is sufficient to power the downstream and upstream circuitry for outputting upstream and downstream signals in response to the received optical signals.
4. The contributing optical splitter/combiner of claim 1 , further comprising at least one amplifier for amplifying the reverse path optical signals.
5. The contributing optical splitter/combiner of claim 4 , wherein the amplifier is powered on when the optical power is detected by the at least one additional detector.
6. The contributing optical splitter/combiner of claim 4 , further comprising at least one laser for re-transmitting the amplified reverse path optical signals.
7. The contributing optical splitter/combiner of claim 6 , wherein the laser is turned on when optical power is detected by the at least one additional detector.
8. The contributing optical splitter/combiner of claim 1 , further comprising a battery that accumulates power from the pump laser for powering an amplifier and laser in the contributing optical splitter/combiner.
9. The contributing optical splitter/combiner of claim 1 , wherein an optical amplifier for the forward path light is optically pumped in the aggregating optical splitter/combiner by at least one of a 980 nm pump laser or a 1480 nm pump laser, and
wherein at least one of a 980 nm pump laser, a 1480 nm pump laser or an 850 nm pump laser provides forward path light to the splitter/combiner for powering the contributing optical splitter/combiner.
10. The contributing optical splitter/combiner of claim 1 , wherein the pump laser has a fiber attenuation of not more than 1 dB of loss per 1 km of fiber.
11. The contributing optical splitter/combiner of claim 1 , wherein the length of fiber between the combiners is not more than 3 km.
12. The contributing optical splitter/combiner of claim 1 , wherein the at least one additional detector is at least one of a Si detector, an InGaAsP detector based on InP, or an InGaAsP detector based on GaAs.
13. The contributing optical splitter/combiner of claim 1 , further comprising a transistor amplifier for amplifying the reverse path optical signals and a laser for re-transmitting the amplified reverse path optical signals,
wherein the one or more detectors are arranged in a transmission line structure and an output of the transmission line structure is provided to the transistor amplifier with an input impedance matched to a transmission line impedance and an output impedance matched to a laser impedance.
14. The contributing optical splitter/combiner of claim 13 , wherein a supply voltage to the one or more detectors is greater than 5 times the rms value of an RF signal output from the transmission line structure to the transistor amplifier, and a supply voltage to the transistor amplifier is less than a supply voltage to the one or more detectors but not higher than a supply voltage to a laser bias circuit.
15. The contributing optical splitter/combiner of claim 14 , wherein the supply voltage to the transistor amplifier is not higher than the voltage drop across a laser used to transmit upstream signals.
16. The contributing optical splitter/combiner of claim 1 , wherein the contributing optical splitter/combiner is one of a plurality of contributing combiners is remotely powered by the aggregating combiner.
17. The contributing optical splitter/combiner of claim 16 , wherein the remote powering by the aggregating combiner contributing optical splitter/combiner causes passive behavior of the contributing optical splitter/combiner such that the contributing combiners do not require additional electrical power.