Triplexer transceiver using parallel signal detection
An optical triplexer transceiver that utilizes parallel signal detection for use in broadband passive optical networks (B-PONs). The triplexer transceiver includes an optical filter comprising a first port coupled to a laser for receiving upstream optical data signals, a second port for passing the upstream optical data signals to a network, and for receiving combined downstream optical data and video signals from the network, the video signals modulated by subcarrier modulation (SCM), and a third port for communicating the combined downstream optical data and video signals to a photodetector constructed and arranged for simultaneously receiving the combined downstream optical data and video signals and converting the optical data and video signals to electrical signals. A plurality of filters are coupled to the photodetector for separating the combined downstream data and video signals, including a low-pass filter for passing the downstream data signals, and a band-pass filter for passing the video signals. The video signals are coherently detected in a number of stages corresponding to stages of SCM applied to the video signals. The triplexer transceiver is adapted to receive optical video signals that have been subjected first and second stages of SCM to move the spectra of the SCM video signals to a higher frequency range that does not overlap with a frequency range of the baseband data signals.
1. An optical triplexer transceiver, comprising:
a laser adapted to be driven by electrical upstream data signals from a user;
an optical filter comprising a plurality of ports, a first port of the optical filter coupled to the laser for receiving upstream optical data signals, a second port of the optical filter for passing the upstream optical data signals to a network, and for receiving combined downstream optical data signals and video signals from the network, and a third port of the optical filter for communicating the combined downstream optical data and video signals to a photodetector constructed and arranged for receiving the combined downstream optical data and video signals and converting the downstream optical data and video signals to electrical signals; and
a plurality of filters coupled to the photodetector for separating the downstream data and video signals, said filters comprising a low pass filter for passing the downstream data signals and a band-pass filter for passing the video signals,
a coherent detector coupled to the band-pass filter for coherently detecting the SCM video signals in two-stages of coherent detection, where each stage corresponds to a stage of SCM
whereby, the separated downstream data and video signals may be communicated to the user;
wherein video signals received by the optical filter comprise a plurality of channels multiplexed by subcarrier modulation (SCM); and
wherein the plurality of video signals are subjected to two stages of SCM.
2. An optical triplexer transceiver, comprising:
a laser adapted to be driven by electrical upstream data signals from a user;
an optical filter comprising a plurality of ports, a first port of the optical filter coupled to the laser for receiving upstream optical data signals, a second port of the optical filter for passing the upstream optical data signals to a network, and for receiving combined downstream optical data signals and video signals from the network, the optical video signals modulated by subcarrier modulation (SCM), and a third port of the optical filter for communicating the combined downstream optical data and video signals to a photodetector constructed and arranged for receiving the combined downstream optical data and video signals and converting the combined downstream optical data and video signals to electrical signals; and
a plurality of filters coupled to the photodetector for separating the combined downstream data and video signals, including a low-pass filter for passing the downstream data signals, and a band-pass filter for passing the video signals; and
a coherent detector for detecting the video signals,
whereby, the separated downstream data and video signals may be communicated to the user.
3. In a broadband passive optical network for transmitting downstream optical data and voice signals, and upstream optical data signals, to and from an optical network terminal, respectively, a method comprising the steps of:
receiving optical baseband data signals;
receiving optical video signals that have been subjected to a first stage of subcarrier modulation (SCM);
employing a second stage of SCM to move the spectra of the SCM video signals to a higher frequency range that does not overlap with a frequency range of the baseband data signals; and
combining the optical baseband data signals with the second-stage SCM shifted video signals and transmitting the combined optical data and SCM video signals to the optical network terminal;
generating upstream optical data signals from upstream electrical signals received from a user;
communicating the upstream optical data signals to a first port of an optical filter;
through a second port of the optical filter, passing the upstream optical data signals to the network, and receiving the combined downstream optical data and SCM video signals from the network;
receiving the combined downstream optical data and SCM video signals from a third port of the optical filter and photodetecting the combined downstream optical data and SCM video signals and converting the downstream optical data and SCM video signals to electrical signals; and
filtering the photodetected downstream optical data and SCM video signals to separate the downstream data and SCM video signals.
4. The method recited in claim 3 , further comprising the step of coherently detecting the SCM video signals.
5. The method recited in claim 3 , wherein the step of coherently detecting the SCM video signals comprises two stages of coherent detection, wherein each stage corresponds to a stage of SCM.