PON supervision using OTDR measurements

A Wavelength Adaptation Module configured to adapt an Optical Time Domain Reflectometry (OTDR) signal for supervision of Optical Network Terminals (ONTs) in a Passive Optical Network (PON), the Wavelength Adaptation Module being adapted to:

• receive an OTDR signal comprising at least one wavelength;
• Red/Blue (R/B) filter the received OTDR signal;
• convert the filtered OTDR signal to a photoelectric current;
• amplitude modulate said photoelectric current and an optical signal having a pre-selected wavelength from a Continuous Wavelength light source, thereby producing an amplitude modulated signal having the pre-selected wavelength of said optical signal;
• and
• output said amplitude modulated signal towards a Remote Node, (RN), wherein said pre-selected wavelength of said optical signal has been pre-selected to enable a splitter in said RN to forward said amplitude modulated signal a dedicated group of ONTs in the PON, thereby supervising fibre links between the RN and the dedicated group of ONTs, and wherein the OTDR signal and the optical signal having the pre-selected wavelength are received as a result of an alarm issued by an ONT belonging to said dedicated group of ONTs.

A method in a Remote Node (RN) in a Passive Optical Network (PON), the PON comprising Optical Network Terminals (ONTs), and a Wavelength Adaptation Module arranged in a fibre path between an Optical Time Domain Reflectometry (OTDR) device and said RN, the RN comprising a passive splitter arrangement, the method comprising:

• receiving an amplitude modulated signal having a pre-selected wavelength from said Wavelength Adaptation Module on a dedicated fibre link, wherein the pre-selected wavelength of the amplitude modulated signal has been pre-selected to enable a splitter in the RN to forward the amplitude modulated signal to a dedicated group of ONTs in the PON;
• outputting said amplitude modulated signal to the dedicated group of ONTs with regards to the pre-selected wavelength of said received amplitude modulated signal;
• and
• filtering out said received amplitude modulated signal, and transmitting said amplitude modulated signal also on a feeder fibre link between an optical line terminal (OLT) and said RN.

A Remote Node (RN) in a Passive Optical Network (PON), the PON comprising Optical Network Terminals (ONTs) and a Wavelength Adaptation Module arranged in a fibre path between an Optical Time Domain Reflectometry (OTDR) device and said RN, said RN comprising a passive splitter arrangement, the RN being adapted to:

• receive an amplitude modulated signal having a pre-selected wavelength from said Wavelength Adaptation Module on a dedicated fibre link, wherein the pre-selected wavelength of the amplitude modulated signal has been pre-selected to enable a splitter in the RN to forward the amplitude modulated signal to a dedicated group of ONTs in the PON;
• output said amplitude modulated signal to the dedicated group of ONTs with regards to the pre-selected wavelength of said received amplitude modulated signal;
• and
• wherein said RN is further adapted to filter out said received amplitude modulated signal, and to transmit said amplitude modulated signal also on a feeder fibre link between an optical line terminal (OLT) and said RN.