The present invention is directed to data communication system and methods. More specifically, various embodiments of the present invention provide a communication interface that is configured to transfer data at high bandwidth using PAM format(s) over optical communication networks. A feedback mechanism is provided for adjusting the transmission power levels. There are other embodiments as well.

A burst-signal reception circuit that receives a differential signal of a burst signal input via a preamplifier. The burst-signal reception circuit includes a differential amplifier to which the differential signal is input via capacitors, an average detection circuit that detects an average of a differential input signal to the differential amplifier, and a differential-offset cancel circuit that operates to cancel a DC voltage level difference of the differential input signal on the basis of output signals of the average detection circuit. Average detection speed of the average detection circuit is configured to be switched according to presence or absence of burst signal reception. The average detection speed is switched to a high-speed side in a head portion of the burst signal and switched to a low-speed side in portions other than the head portion.

In various embodiments, the present disclosure includes a system for sending 50 gigabits per second (Gbps), 75 Gbps, and 100 Gbps at 50 gigabaud (GBaud) for passive optical networks (PON) downstream and upstream. The system allows for transmission of three data rates at a single baud-rate while only using 2-bits of information per sample. A motivation for sending three data rates at a single baud-rate is to allow for further granularity in the control of the data-rates for downstream and upstream traffic in a flexible PON system based on the link margin. For example, the system can use non-return-to-zero (NRZ) at 50 GBaud for 50 Gbps and can use four-level pulse-amplitude modulation (PAM-4) at 50 GBaud for 100 Gbps. In addition for 75 Gbps, a double square-8 (DSQ-8) constellation can be used at 50 GBaud.

Disclosed herein are methods, devices, and system for beam forming and beam steering within ultra-wideband, wireless optical communication devices and systems. According to one embodiment, a free space optical (FSO) communication apparatus is disclosed. The FSO communication apparatus includes an array of optical sources wherein each optical source of the array of optical sources is individually controllable and each optical source configured to have a transient response time of less than 500 picoseconds (ps).

This invention relates to a receiver configured to exploit physical phenomena of a memory in an electro-optical converter of an emitter (e.g., LED) at a transmitting end. The memory can be described as a state that is a function of an input signal of the emitter, while the emitted light is a function of the state. An incoming symbol bit sequence and corresponding state(s) of the electro-optical converter are estimated (e.g., in terms of time varying carrier concentration or charge in a quantum well) to derive a decision for a state of a received symbol. This estimation can be done for multiple levels of incoming data (e.g., at least for hypothesized binary values).

In various embodiments, the present disclosure includes a system for sending 50 gigabits per second (Gbps), 75 Gbps, and 100 Gbps at 50 gigabaud (GBaud) for passive optical networks (PON) downstream and upstream. The system allows for transmission of three data rates at a single baud-rate while only using 2-bits of information per sample. A motivation for sending three data rates at a single baud-rate is to allow for further granularity in the control of the data-rates for downstream and upstream traffic in a flexible PON system based on the link margin. For example, the system can use non-return-to-zero (NRZ) at 50 GBaud for 50 Gbps and can use four-level pulse-amplitude modulation (PAM-4) at 50 GBaud for 100 Gbps. In addition for 75 Gbps, a double square-8 (DSQ-8) constellation can be used at 50 GBaud.