Methods, systems, and devices for network communications to reduce optical beat interference (OBI) in upstream communications are described. For example, a fiber node may provide a narrow band seed source to injection lock upstream laser diodes. Therefore, upstream communications from each injection locked laser diode may primarily include the wavelength associated with each seed source. The seed sources may be unique to each end device and configured to minimize OBI. That is, the upstream laser diodes may be generic, but the received seed source may enable upstream communications at varying wavelengths. The fiber node may provide each seed source by filtering (e.g., by a grating filter) a broadband light source.

Methods, systems, and devices for network communications to reduce optical beat interference (OBI) in upstream communications are described. For example, a fiber node may provide a narrow band seed source to injection lock upstream laser diodes. Therefore, upstream communications from each injection locked laser diode may primarily include the wavelength associated with each seed source. The seed sources may be unique to each end device and configured to minimize OBI. That is, the upstream laser diodes may be generic, but the received seed source may enable upstream communications at varying wavelengths. The fiber node may provide each seed source by filtering (e.g., by a grating filter) a broadband light source.

Directional wireless drop systems are provided. These systems include a tap unit that is connected to a communications line of the broadband network; a cable modem unit connected to the tap unit; a plurality of wireless routers connected to the cable modem unit; and a directional antenna unit that is connected to at least a first of the wireless routers. Each wireless router is associated with a respective one of a plurality of subscriber premises that are served by the directional wireless drop system and is configured to communicate with at least one device that is located at the respective one of plurality of subscriber premises.

Directional wireless drop systems are provided. These systems include a tap unit that is connected to a communications line of the broadband network; a cable modem unit connected to the tap unit; a plurality of wireless routers connected to the cable modem unit; and a directional antenna unit that is connected to at least a first of the wireless routers. Each wireless router is associated with a respective one of a plurality of subscriber premises that are served by the directional wireless drop system and is configured to communicate with at least one device that is located at the respective one of plurality of subscriber premises.

Apparatus, systems, and methods include leveraging the angular dependence of the angle of arrival of the incoming optical signal at an optical resonator and the output response signal to adjust the operating condition of the optical resonator. The optical resonator is dynamically tuned by rotating the optical resonator to optimize signal-to-noise ratio or other parameters for different modulation formats of the incoming optical signal or other different operating conditions.

Methods, systems, and devices for network communications to reduce optical beat interference (OBI) in upstream communications are described. For example, a fiber node may provide a narrow band seed source to injection lock upstream laser diodes. Therefore, upstream communications from each injection locked laser diode may primarily include the wavelength associated with each seed source. The seed sources may be unique to each end device and configured to minimize OBI. That is, the upstream laser diodes may be generic, but the received seed source may enable upstream communications at varying wavelengths. The fiber node may provide each seed source by filtering (e.g., by a grating filter) a broadband light source.

Methods, systems, and devices for network communications to reduce optical beat interference (OBI) in upstream communications are described. For example, a fiber node may provide a narrow band seed source to injection lock upstream laser diodes. Therefore, upstream communications from each injection locked laser diode may primarily include the wavelength associated with each seed source. The seed sources may be unique to each end device and configured to minimize OBI. That is, the upstream laser diodes may be generic, but the received seed source may enable upstream communications at varying wavelengths. The fiber node may provide each seed source by filtering (e.g., by a grating filter) a broadband light source.

A self-coherent optical data receiver configured to use direct detection of optical signals that is compatible with full (amplitude/phase) electric-field reconstruction. To enable the latter, the direct-detected optical signal includes CW light whose carrier frequency is spectrally aligned with a roll-off edge of the data-modulated portion of the signal. In an example embodiment, the receiver may employ two digital filters placed upstream and downstream, respectively, of the field-reconstruction circuit. The upstream filter is configurable to at least partially cancel the effects of SSBI caused by the direct detection. The downstream filter can be configured to perform electronic dispersion compensation and/or electronic polarization demultiplexing. In different embodiments, a filter controller may operate to adaptively change the filter coefficients of the upstream filter based on different signals generated within the digital receive chain. For example, the filter controller can use either input or output of the downstream filter for this purpose.

A self-coherent optical data receiver configured to use direct detection of optical signals that is compatible with full (amplitude/phase) electric-field reconstruction. To enable the latter, the direct-detected optical signal includes CW light whose carrier frequency is spectrally aligned with a roll-off edge of the data-modulated portion of the signal. In an example embodiment, the receiver may employ two digital filters placed upstream and downstream, respectively, of the field-reconstruction circuit. The upstream filter is configurable to at least partially cancel the effects of SSBI caused by the direct detection. The downstream filter can be configured to perform electronic dispersion compensation and/or electronic polarization demultiplexing. In different embodiments, a filter controller may operate to adaptively change the filter coefficients of the upstream filter based on different signals generated within the digital receive chain. For example, the filter controller can use either input or output of the downstream filter for this purpose.

An optical receiver is provided with: an optical reception circuit which receives wavelength multiplexed light including signal light, converts the signal light into an electrical signal by coherent detection of the signal light using local oscillation light, and outputs the power of the local oscillation light, the bit error rate of the signal light and the electrical signal; and a controller which monitors the power of the local oscillation light and the bit error rate, calculates the signal-to-noise ratio of the signal light on the basis of the power of the local oscillation light and the bit error rate, and finds the number of wavelengths of the wavelength multiplexed light and the power per wavelength of the signal light on the basis of the signal-to-noise ratio and the power of the local oscillation light.