A system and method for performing an in-service optical time domain reflectometry test, an in-service insertion loss test, and an in-service optical frequency domain reflectometry test using a same wavelength as the network communications for point-to-point or point-to-multipoint optical fiber networks while maintaining continuity of network communications are disclosed.

A method for detecting an optical network unit (ONU) in a passive optical network (PON), an ONU, a PON and an optical line terminal (OLT) are disclosed. In an embodiment the method include detecting an ONU identity code in an open uplink empty window or an empty timeslot, wherein the ONU identity code is a specific code stream sequence of the ONU that identifies a single ONU of the plurality of ONUs included in the PON system during the open uplink empty window or the empty timeslot and determining that the single ONU corresponding to the ONU identity code is a rogue ONU according to the ONU identity code.

A method for activating an ONU in a multi-wavelength PON. Other ONUs may be already active and transmit upstream signals to the OLT on various upstream channels. The new ONU transmits an activation signal superimposed to such upstream signals. Since the ONU may include an uncalibrated tunable transmitter, initially the activation signal wavelength might be different from that upon which the ONU shall be activated. The activation signal optical power is lower than the other upstream signals, so as not to impair their reception at the OLT. The OLT operates the ONUs already active on the upstream channel on which the new ONU shall be activated to suspend transmission for one or more time gaps, during which the OLT detects the activation signal. This improves activation signal detection conditions, thereby allowing to increase its bitrate. An acceptable duration of the activation procedure can then be achieved.

Embodiments of the invention disclose a communication method which includes: receiving, by the optical network unit (ONU) by using the first port or the second port, a wavelength switching request message delivered by the optical line terminal (OLT), where the wavelength switching request message carries second wavelength channel information and port information that is of the second port; switching, by the ONU, an operating wavelength channel of an optical module connected to the second port from a first wavelength channel to a second wavelength channel corresponding to the second wavelength channel information; and sending, by the ONU, a wavelength switching complete message to the OLT by using the first port. According to the communication method provided in embodiments of the present invention, quick wavelength switching is performed based on the second port, so that a service is not interrupted in a wavelength switching process, and user experience is better.

Digital information can be carried on the fiber leg of an access network using binary modulation. Binary modulated data received at an O/E node can then be modulated onto an analog waveform using quadrature amplitude modulation or some other technique for modulating an analog waveform and transmitted over, for example, the coaxial leg of the network. The O/E node may also receive an analog signal, over the coaxial leg, modulated to carry upstream data from subscriber devices. The O/E node may demodulate the upstream signal to recover the upstream data and forward that upstream data over the fiber leg using a binary modulated optical signal.

Embodiments relate to providing simultaneous digital and analog services in optical fiber-based distributed radio frequency (RF) antenna systems (DASs), and related components and methods. A multiplex switch unit associated with a head-end unit of a DAS can be configured to receive a plurality of analog and digital downlink signals from one or more sources, such as a service matrix unit, and to assign each downlink signal to be transmitted to one or more remote units of the DAS. In one example, when two or more downlink signals are assigned to be transmitted to the same remote unit, a wave division multiplexer/demultiplexer associated with the multiplex switch unit can be configured to wave division multiplex the component downlink signals into a combined downlink signal for remote side transmission and to demultiplex received combined uplink signals into their component uplink signals for head-end side transmission.

Digital information can be carried on the fiber leg of an access network using binary modulation. Binary modulated data received at an O/E node can then be modulated onto an analog waveform using quadrature amplitude modulation or some other technique for modulating an analog waveform and transmitted over, for example, the coaxial leg of the network. The O/E node may also receive an analog signal, over the coaxial leg, modulated to carry upstream data from subscriber devices. The O/E node may demodulate the upstream signal to recover the upstream data and forward that upstream data over the fiber leg using a binary modulated optical signal.

A system and method for performing an in-service optical time domain reflectometry test, an in-service insertion loss test, and an in-service optical frequency domain reflectometry test using a same wavelength as the network communications for point-to-point or point-to-multipoint optical fiber networks while maintaining continuity of network communications are disclosed.

In one embodiment, a method for passive optical network (PON) communication includes broadcasting, by an optical line terminal (OLT), a first message including a first start time of a first quiet window and a first allocation identification number (Alloc-ID), where the first Alloc-ID indicates a first supported upstream line rate associated with the first quiet window. The method also includes receiving, by the OLT from a first optical network unit (ONU) during the first quiet window, a first serial number response, wherein a first transmitting upstream line rate of the first ONU is equal to the first supported upstream line rate.

An optical line terminal (OLT) channel termination (CT) comprises a receiver configured to receive an upstream message which comprises a correlation tag from an optical network unit (ONU), wherein the correlation tag represents a unique number, a processor coupled to the receiver and configured to process the upstream message, and generate a downstream message based on the upstream message, wherein the downstream message comprises the correlation tag, and a transmitter coupled to the processor and configured to transmit the downstream message to the ONU.