Prevention of collision for time division multiplexing optical network, apparatus and method thereof

A method for preventing collision of upstream signals, suitable for a TDM PON, the method comprising:

• splitting a first optical signal into a detection optical signal and a data optical signal, wherein the first optical signal is provided by an optical network unit (ONU);
• converting the detection optical signal into a first electrical signal;
• generating a control signal according to the first electrical signal;
• and
• determining whether to guide the data optical signal to a photoresist device according to the control signal, wherein the data optical signal is guided to the photoresist device while the ONU is in an continuous wave (CW) mode if the continuous time of the first electrical signal being greater than a threshold value is longer than a predetermined time;
• and the data optical signal is not guided while the ONU is in an burst mode if the continuous time of the first electrical signal being greater than the threshold value is not longer than the predetermined time.

A TDM PON system for preventing collision of upstream signals, comprising:

• an optical line termination (OLT);
• a first optical coupler device, for splitting and coupling optical signals;
• a plurality of end-user devices, wherein each of the end-user devices comprises:
• an ONU;
• and
• a signal collision prevention apparatus, coupled to the ONU, for receiving a first optical signal from the ONU and splitting the first optical signal into a detection optical signal and a data optical signal, and for determining whether to guide the data optical signal to a photoresist device according to the detection optical signal;
• and
• a plurality of optical fibers, for connecting the OLT and the first optical coupler device and also connecting the first optical coupler device and the end-user devices, wherein each of the signal collision prevention apparatuses comprises:
• a second optical coupler device, coupled to the ONU, for receiving the first optical signal and splitting the first optical signal into the detection optical signal and the data optical signal;
• an O/E, coupled to the second optical coupler device, for converting the detection optical signal into a first electrical signal;
• a control system, coupled to the O/E, for generating a control signal according to the first electrical signal;
• and
• an optical signal switch module, coupled to the second optical coupler device and the control system, for determining whether to guided the data optical signal to the photoresist device according to the control signal,
• wherein the optical signal switch module guided the data optical signal to the photoresist device while the ONU is in an continuous wave (CW) mode if the time of the first electrical signal being greater than a threshold value is longer than a predetermined time, and the optical signal switch module allows the signal collision prevention apparatus to output the data optical signal while the ONU is in an burst mode if the time of the first electrical signal being greater than the threshold value is not longer than the predetermined time.