Systems, methods, and devices are disclosed for implementing photonic links. Methods include transmitting light using an optical emitter, splitting, using an input coupler, the light into a first path and a second path, the first path being provided to a modulator, and the second path being provided to a phase shifter, and combining, using an output coupler, an output of the modulator and an output of the phase shifter. Methods further include identifying a modulator phase angle that reduces a third order distortion at an output of the output coupler, applying a first bias voltage to a modulator to maintain the identified modulator phase angle, and applying a control signal to the phase shifter to maintain a phase difference between an output of the modulator and an output of a phase shifter.

Various indirect feedback tuning apparatuses and methods for tuning photonic systems are enabled. For instance, a system can perform operations, comprising: determining a temperature of an optical device, determining, based on the temperature of the optical device and a feedback model, a tuning input to stabilize an optical signal, and performing, based on the tuning input, feedback tuning, wherein the feedback tuning comprises thermal tuning and electrical tuning.

A photonics system includes a transmit photonics module and a receive photonics module. The photonics system also includes a transmit waveguide coupled to the transmit photonics module, a first optical switch integrated with the transmit waveguide, and a diagnostics waveguide optically coupled to the first optical switch. The photonics system further includes a receive waveguide coupled to the receive photonics module and a second optical switch integrated with the receive waveguide and optically coupled to the diagnostics waveguide.

Provided is an optical transceiver including a reference tunable laser module configured to generate and output light of a reference wavelength; a first general tunable laser module configured to generate and output light of a first wavelength; and a controller configured to control a tuning operation of the first wavelength of the first general tunable laser module, based on information about a relationship between the reference wavelength and the first wavelength.

Embodiments of the present disclosure relate to method, device and computer-readable medium for communication in a Passive Optical Network (PON). The method comprises receiving a first sequence from an Optical Network Unit (ONU) the first sequence being transmitted by using a reference sequence shared with the Optical Line Terminal (OLT) based on a first set of parameters associated with an uplink transmission from the ONU to the OLT; determining parameter adjustment information based on the first sequence and the reference sequence, the parameter adjustment information being used to adjust at least one parameter in the first set of parameters associated with the uplink transmission, to cause transmission property of the uplink to satisfy a predetermined condition; and transmitting the parameter adjustment information to the ONU.

An autonomous failure recovery method and a system for a fiber-optic communication system. The method comprises acquiring a real-time operation timing sequence of a digital high-speed serial transceiver of a fiber-optic communication system, and comparing the operation timing sequence against a pre-stored reference timing sequence of normal operation of the serial transceiver; when the operation timing sequence is inconsistent with the reference timing sequence, determining that failure of an optical path of the fiber-optic communication system has occurred; sending a pre-determined autonomous recovery timing sequence to the serial transceiver when the optical path is in a failure state, and performing an autonomous failure recovery operation of the fiber-optic communication system in response to the autonomous recovery timing sequence. The method and the system for a fiber-optic communication system achieve automatic troubleshooting and autonomous failure recovery for an optical path failure, thereby improving efficiency of troubleshooting and system recovery.

The disclosure provides for a method for reacquiring a communication link between a first communication device and a second communication device. The method includes using one or more processors of the first communication device to receive historical data related to the first communication device and an environment surrounding the first communication device. The one or more processors are then used to determine one or more trends in the historical data related to fading of the communication link. Based on the one or more trends, the one or more processors are used to determine a starting time and an initial search direction for a search for the communication link. The one or more processors then execute the search at the starting time from the initial search direction.

[Problem] To allow addition of new functions to an optical module at a low cost.

[Solution] An optical transceiver 11a includes a CPU 21 configured to perform download control of a program for executing an additional function to be newly added to the optical transceiver 11a, a wireless transmitting and receiving device 22 configured to receive, in accordance with the download control, the program from a terminal device 13 that stores various programs, and a memory unit 23 configured to store the program that is received. The CPU 21 is configured to perform, by interrupting a monitoring and control signal from a transmission device 12, control to write data related to transmission and reception processing of a Tx 25a and a Rx 26a in accordance with execution of the programs stored in the memory unit 23 in a storage area at a specific address of an EEPROM 24.

A passive optical network power meter includes at least one memory and the computer program code configured to, with at least one processor, cause the passive optical network power meter to: determine an extinction ratio for the optical network unit based on a first plurality of consecutive optical transmissions indicative of a first logic value during a first time interval and a second plurality of consecutive optical transmissions indicative of a second logic value during a second time interval, the second time interval being subsequent to the first time interval; detect an average transmit power for the optical network unit based on a third plurality of consecutive optical transmissions during a third time interval, the third plurality of consecutive optical transmissions indicative of alternating first and second logic values; and identify an operating state of the optical network unit based on the extinction ratio and the average transmit power.

Methods and apparatus for coherent transmitter calibration are provided that employ direct detection (DD) using one single photodetector (PD). The provided method and apparatus do not require hardware for coherent reception, or additional ADCs for quality control. An additional optical tone is added to a QAM optical signal that is outside the band of the QAM optical signal. The result of this is that after direct detection, there is a correlation between the real and imaginary parts, and the imaginary part can be recovered with a Hilbert transform. The estimated QAM optical signal obtained by direct detection is used to perform a transmitter factory calibration method to calibrate for one or more transmitter impairments and/or to perform in-line self-calibration.