Apparatus and method for tracking optical wavelength in WDM passive optical network using loop-back light source
AssigneeSamsung Electronics Co., Ltd.
InventorsDae-Kwang Jung, Yun-Je Oh, Seong-Taek Hwang
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Abstract
An optical wavelength tracking apparatus and method in a wavelength division multiplexed (WDM) passive optical network (PON) in which a central office (CO) having a multi-frequency light source is connected to a plurality of optical network units (ONUs) having loop-back light sources through a WDM MUX/DEMUX in a remote node (RN). The power levels of downstream and upstream WDM optical signals are measured. The WDM wavelengths of the multi-frequency light source and the WDM MUX/DEMUX are controlled to be nearly identical in order to minimize the difference between the power levels of the downstream and upstream WDM optical signals.
Claims16
An optical wavelength tracking apparatus in a wavelength division multiplexed (WDM) passive optical network (PON) in which a central office (CO) having a multi-frequency light source is connected to a plurality of optical network units (ONUs) having loop-back light sources through a WDM multiplexer/demultiplexer (MUX/DEMUX) in a remote node (RN), the apparatus comprising:
- a first optical power measurer for measuring a power level of a downstream WDM optical signal for the plurality of ONUs that is directed from the multi-frequency light source to the WDM MUX/DEMUX;
- a second optical power measurer for measuring a power level of an upstream WDM optical signal received from the loop-back light sources of the ONUs through the WDM MUX/DEMUX;
- and
- a control unit for controlling the WDM wavelengths of the multi-frequency light source and the WDM MUX/DEMUX to be nearly identical in order to minimize the difference between the power levels of the measured downstream and upstream WDM optical signals.
An optical wavelength tracking apparatus in a wavelength division multiplexed (WDM) passive optical network (PON) in which a central office (CO) having a multi-frequency light source is connected to a plurality of optical network units (ONUs) having loop-back light sources through a WDM multiplexer/demultiplexer (MUX/DEMUX) in a remote node (RN), the apparatus comprising:
- a first optical divider for branching off a section of a downstream WDM optical signal for the ONUs directed from the multi-frequency light source to the WDM MUX/DEMUX;
- a first optical receiver for receiving the branched optical signal from the first optical divider and outputting a voltage at the power level of the received optical signal as a reference voltage;
- a second optical divider for branching off a section of an upstream WDM optical signal received from the loop-back light sources through the WDM MUX/DEMUX;
- a second optical receiver for receiving the branched optical signal from the second optical divider and outputting a voltage at the power level of the received optical signal as a monitoring voltage;
- a temperature control unit (TCU) mounted to the multi-frequency light source;
- and
- a controller for controlling the WDM wavelengths of the multi-frequency light source and the WDM MUX/DEMUX to be nearly identical by adjusting the temperature of the multi-frequency light source by means of the TCU in order to minimize the difference between the reference voltage and the monitoring voltage.
An optical wavelength tracking method in a wavelength division multiplexed (WDM) passive optical network (PON) in which a central office (CO) having a multi-frequency light source is connected to a plurality of optical network units (ONUs) having loop-back light sources through a WDM multiplexer/demultiplexer (MUX/DEMUX) in a remote node (RN), the method comprising the steps of:
- (a) branching off a section of a downstream WDM optical signal for the ONUs directed from the multi-frequency light source to the WDM MUX/DEMUX,
- (b) measuring the power level of the branched optical signal as a reference voltage,
- (c) branching off a section of an upstream WDM optical signal received from the loop-back light sources through the WDM MUX/DEMUX,
- (d) measuring the power level of the branched optical signal as a monitoring voltage;
- and
- (e) controlling the WDM wavelengths of the multi-frequency light source and the WDM MUX/DEMUX to be nearly identical by adjusting the temperature of the multi-frequency light source in order to minimize the difference between the reference voltage and the monitoring voltage.
An optical wavelength tracking method in a wavelength division multiplexed (WDM) passive optical network (PON) in which a central office (CO) having a multi-frequency light source connected to a plurality of optical network units (ONUs) having loop-back light sources through a WDM multiplexer/demultiplexer (MUX/DEMUX) in a remote node (RN), the method comprising the steps of:
- (a) branching off a section of a downstream WDM optical signal for the ONUs directed from the multi-frequency light source to the WDM MUX/DEMUX,
- (b) measuring the power level of the branched optical signal as a reference voltage,
- (c) branching off a section of an upstream WDM optical signal received from the loop-back light sources through the WDM MUX/DEMUX, and measuring the power level of the branched optical signal as a monitoring voltage;
- and
- (d) controlling the WDM wavelengths of the multi-frequency light source and the WDM MUX/DEMUX to be nearly identical by adjusting the temperature of the multi-frequency light source in order to minimize the difference between the reference voltage and the monitoring voltage.
Dependencies are inferred from the claim text.