A receiver system is provided for receiving a coherent Pulse Amplitude Modulation (PAM) encoded signal. The receiver system may include an optical polarization component configured to modulate a polarization of the received coherent PAM encoded signal. The receiver system may further include a digital signal processor (DSP) configured to perform polarization recovery between the received coherent PAM encoded signal and the LO signal using a first control loop, and to perform phase recovery between the received coherent PAM encoded signal and the LO signal using a second control loop.

Systems and methods for synchronize word correlation. The methods comprise: obtaining first values that each indicate a likelihood or probability that a respective timeslot in a symbol timing window of a carrier wave is meant or expected to include energy; multiplying, by the correlator, the first values respectively by correlation coefficients to produce a plurality of products (wherein at least one of the correlation coefficients comprises a negative coefficient value); generating a correlation value by combining the products together; determining whether a synchronization word has been detected with a given amount of likelihood based on the correlation value; and causing symbol timing synchronization at a receiver when a determination is made that the synchronization word has been detected with the given amount of likelihood based on the correlation value.

Provided is a burst mode optical transmitter capable of preventing an optical signal from being output from a light source during burst mode disable time through an arithmetic circuit configured to remove an idle signal included in a MAC electrical signal by using a MAC electrical signal and a burst mode control signal.

The invention relates to a method and apparatus of operating a bidirectional optical transmission link. The optical transmission link includes a first and a second optical transceiver at a dedicated end of the optical transmission link and an optical path connecting the first and second optical transceiver. The optical transceivers apply the methods of converting an electrical digital transmit signal into an electrical PAM-n transmit signal, pre-emphasizing the electrical PAM-n transmit signal) by digital filtering and using the pre-emphasized electrical PAM-n signal.sub.2) as modulating signal for optically modulating an optical carrier signal. The optical modulation method deployed is configured to create an optical PAM-n transmit signal with a positive or negative chirp. For initializing the optical transmission link (100), an initialization process is performed in which at least one loop including the following steps is run through creating, in the first optical transceiver, an optical PAM-n training transmit signal and transmitting it to the second optical transceiver, the optical PAM-n training transmit signal being created using an electrical PAM-n training transmit signal including a binary training sequence. Initial values for filter parameters are used for pre-emphasizing the electrical PAM-n training transmit signal and an initial value is used for a chirp parameter that defines the positive or negative chirp of the optical PAM-n training transmit signal receiving, in the second optical transceiver, the optical PAM-n training transmit signal as an optical PAM-n training receive signal using direct detection. The optical PAM-n training receive signal is converted into an electrical PAM-n training receive signal. The method includes obtaining sampled values of the electrical PAM-n training receive signal (RP.sub.el,1) by sampling this signal at predetermined points in time; and using the sampled values obtained and corresponding sampled values of an ideal electrical PAM-n transmit signal to determine operating values for the filter parameters and an operating value for the chirp parameter.

The invention relates to a method and apparatus of operating a bidirectional optical transmission link. The optical transmission link includes a first and a second optical transceiver at a dedicated end of the optical transmission link and an optical path connecting the first and second optical transceiver. The optical transceivers apply the methods of converting an electrical digital transmit signal into an electrical PAM-n transmit signal, pre-emphasizing the electrical PAM-n transmit signal) by digital filtering and using the pre-emphasized electrical PAM-n signal.sub.2) as modulating signal for optically modulating an optical carrier signal. The optical modulation method deployed is configured to create an optical PAM-n transmit signal with a positive or negative chirp. For initializing the optical transmission link (100), an initialization process is performed in which at least one loop including the following steps is run through creating, in the first optical transceiver, an optical PAM-n training transmit signal and transmitting it to the second optical transceiver, the optical PAM-n training transmit signal being created using an electrical PAM-n training transmit signal including a binary training sequence. Initial values for filter parameters are used for pre-emphasizing the electrical PAM-n training transmit signal and an initial value is used for a chirp parameter that defines the positive or negative chirp of the optical PAM-n training transmit signal receiving, in the second optical transceiver, the optical PAM-n training transmit signal as an optical PAM-n training receive signal using direct detection. The optical PAM-n training receive signal is converted into an electrical PAM-n training receive signal. The method includes obtaining sampled values of the electrical PAM-n training receive signal (RP.sub.el,1) by sampling this signal at predetermined points in time; and using the sampled values obtained and corresponding sampled values of an ideal electrical PAM-n transmit signal to determine operating values for the filter parameters and an operating value for the chirp parameter.

A control device of modulating signal generates high-side signal and low-side signal. The high-side signal takes level in accordance with level of AC component of a monitor signal obtained by photoelectric conversion of modulated light, when the polarity of the AC component is positive, or its magnitude is zero. The high-side signal further takes constant level when the polarity of the AC component is negative. The low-side signal takes constant level when the polarity of the AC component is positive. The low-side signal further takes level in accordance with level of the AC component when the polarity of the AC component is negative, or its magnitude is zero. Then, the control device adjusts level of the modulating signal based on a greatest value of absolute values of levels taken by the high-side signal and a greatest value of absolute values of levels taken by the low-side signal.

A control device of modulating signal generates high-side signal and low-side signal. The high-side signal takes level in accordance with level of AC component of a monitor signal obtained by photoelectric conversion of modulated light, when the polarity of the AC component is positive, or its magnitude is zero. The high-side signal further takes constant level when the polarity of the AC component is negative. The low-side signal takes constant level when the polarity of the AC component is positive. The low-side signal further takes level in accordance with level of the AC component when the polarity of the AC component is negative, or its magnitude is zero. Then, the control device adjusts level of the modulating signal based on a greatest value of absolute values of levels taken by the high-side signal and a greatest value of absolute values of levels taken by the low-side signal.

Systems and methods for performing operations based on LIDAR communications are described. An example device may include one or more processors and a memory coupled to the one or more processors. The memory includes instructions that, when executed by the one or more processors, cause the device to receive data associated with a modulated optical signal emitted by a transmitter of a first LIDAR device and received by a receiver of a second LIDAR device coupled to a vehicle and the device, generate a rendering of an environment of the vehicle based on information from one or more LIDAR devices coupled to the vehicle, and update the rendering based on the received data. Updating the rendering includes updating an object rendering of an object in the environment of the vehicle. The instructions further cause the device to provide the updated rendering for display on a display coupled to the vehicle.

Systems and methods for performing operations based on LIDAR communications are described. An example device may include one or more processors and a memory coupled to the one or more processors. The memory includes instructions that, when executed by the one or more processors, cause the device to receive data associated with a modulated optical signal emitted by a transmitter of a first LIDAR device and received by a receiver of a second LIDAR device coupled to a vehicle and the device, generate a rendering of an environment of the vehicle based on information from one or more LIDAR devices coupled to the vehicle, and update the rendering based on the received data. Updating the rendering includes updating an object rendering of an object in the environment of the vehicle. The instructions further cause the device to provide the updated rendering for display on a display coupled to the vehicle.

A method and system for multipulse-pulse position modulation optical transmission that includes selecting a multipulse-pulse position modulation having a symbol alphabet having an upper-bound symbol alphabet size, and determining, based on at least one transmission characteristic associated with a transmitter, a subset of symbols of the selected symbol alphabet capable of being transmitted by the transmitter, the subset of symbols having a set of binary codewords. The method and system may include identifying two-symbol concatenation of binary codewords in the set of binary codewords, calculating a cross correlation of binary codeword in the set of binary code words through every two-symbol concatenation, determining a set of one or more acceptable codeword combinations by eliminating a portion of two-symbol concatenation of codewords corresponding to overlapping peaks in the respective calculated cross correlations, and transmitting, by the transmitter via an optical communication channel, information encoded based on the determined acceptable codeword combinations.