A network or system in which a hub or primary node may communicate with a plurality of leaf or secondary nodes. The hub node may operate or have a capacity greater than that of the leaf nodes. Accordingly, relatively inexpensive leaf nodes may be deployed to receive data carrying optical signals from, and supply data carrying optical signals to, the hub node. One or more connections may couple each leaf node to the hub node, whereby each connection may include one or more spans or segments of optical fibers, optical amplifiers, optical splitters/combiners, and optical add/drop multiplexer, for example. Optical subcarriers may be transmitted over such connections, each carrying a data stream. The subcarriers may be generated by a combination of a laser and a modulator, such that multiple lasers and modulators are not required, and costs may be reduced. As the bandwidth or capacity requirements of the leaf nodes change, the number of subcarriers, and thus the amount of data provided to each node, may be changed accordingly. Each subcarrier within a dedicated group of subcarriers may carry OAM or control channel information to a corresponding leaf node, and such information may be used by the leaf node to configure the leaf node to have a desired bandwidth or capacity.

An optical transmitter that outputs an optical signal with a pulse amplitude modulation (PAM) configuration is disclosed. The optical transmitter includes a light-generating device and a driver. The light-generating device has non-linearity in a transfer characteristic between the electrical driving signal and the optical signal. The driver includes a PAM signal generator, a level controller, and an output driver. The PAM signal generator receives the input electrical signal and outputs a PAM signal. The level controller adjusts the electrical levels of the PAM signal based on the non-linear transfer characteristic of the light-generating device, where the electrical levels set the optical levels of the optical signal with preset ratios. The output driver generates the driving signal by superposing the electrical levels adjusted by the level controller with the PAM signal provided from the PAM signal generator.

In an embodiment, a laser includes a gain section. The gain section includes an active region, an upper separate confinement heterostructure (SCH), and a lower SCH. The upper SCH is above the active region and has a thickness of at least 60 nanometers (nm). The lower SCH is below the active region and has a thickness of at least 60 nm.

An apparatus includes a plurality of VCSELs, a master laser, one or more electrical drivers, and an optical combiner. The master laser is configured to transmit laser light to the VCSELs to optically lock wavelengths of the VCSELs. The one or more electrical drivers are connected to directly electrically modulate the VCSELs in a manner responsive to one or more digital data stream. The optical combiner is configured to combine light received from, at least, a pair of the VCSELs into an optical carrier with a substantially phase digital data modulation.

Systems and methods for controlling laser modulation in burst communications. In a start-up phase, a drive circuitry sequentially applies first and second drive currents to a laser diode such that it produces a first and second optical output, respectively. A compensating current source coupled to the laser diode provides a current related to the first and second drive currents to maintain a combined current flowing through an impedance connected to the laser diode at a substantially constant level during the start-up phase. An optical sensor measures the first and second optical outputs, and a controller uses values of the first and second drive currents, the outputs from the optical sensor, and at least one supplied input value to provide control values for the drive circuitry for controlling operating current of the laser diode during a subsequent operating phase, wherein information is transmitted in at least one burst.

An interposer device includes a substrate that includes a laser source chip interface region, a silicon photonics chip interface region, an optical amplifier module interface region. A fiber-to-interposer connection region is formed within the substrate. A first group of optical conveyance structures is formed within the substrate to optically connect a laser source chip to a silicon photonics chip when the laser source chip and the silicon photonics chip are interfaced to the substrate. A second group of optical conveyance structures is formed within the substrate to optically connect the silicon photonics chip to an optical amplifier module when the silicon photonics chip and the optical amplifier module are interfaced to the substrate. A third group of optical conveyance structures is formed within the substrate to optically connect the optical amplifier module to the fiber-to-interposer connection region when the optical amplifier module is interfaced to the substrate.

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.

An optical communication module includes a module board housed in a casing, a VCSEL and a driving IC mounted on a mounting surface of the module board, a lens holder mounted on the mounting surface of the module board, a lens block held by the lens holder, a plurality of thermal vias passing through the module board, and a first fixing screw and a second fixing screw passing through the module board to be screwed into the casing so as to press a back surface of the module board against a bottom surface of the casing, and the first fixing screw and the second fixing screw are each arranged in a region between the plug connector and the lens holder and on either outer side of the lens holder.

An optical module for preventing laser beam leakage and a control method thereof are disclosed. The optical module including a current control circuit, a first transistor, a laser, and a laser control unit. The laser control unit is configured to: if it is detected that an optical fiber is inserted in the optical fiber interface, perform control to turn on the laser, or if it is detected that no optical fiber is inserted in the optical fiber interface, control the laser to remain in an off state. A laser beam is effectively prevented from causing human bodily injury when an optical fiber is not inserted in an optical fiber interface.

A transmitter can include a laser operable to output an optical signal; a digital signal processor operable to receive data and provide a plurality of electrical signals based on the data; and a modulator operable to modulate the optical signal to provide a plurality of optical subcarriers based on the plurality of electrical signals. One of the plurality of subcarriers carries first information indicative of a first portion of the data in a first time slot and second information indicative of a second portion of the data in a second time slot. The first information is associated with a first node remote from the transmitter and the second information is associated with a second node remote from the transmitter. A receiver as well as a system also are described.