An underwater communications system may include a first device and a second device being movable relative to one another. The first device may include a first laser transmitter configured to generate a first laser beam having a selectable spatiotemporal beam shape from among a plurality thereof, and a first controller coupled to the first laser transmitter and configured to select a spatiotemporal beam shape for the first laser beam from among the spatiotemporal beam shapes. The second device may include a second laser receiver configured to receive the first laser beam, and a second controller coupled to the second laser receiver.

An apparatus is provided for using a square wave digital chirp signal for optical chirp range detection. A laser source emits an optical signal and a RF waveform generator generates an input digital chirp signal based on the square wave digital chirp signal. A frequency of the optical signal is modulated based on the input digital chirp signal. A splitter divides the optical signal into a transmit optical signal and a reference optical signal. A detector combines the reference optical signal and a return optical signal from an object. The detector generates an electrical output signal based on the combined reference optical signal and the return optical signal. A processor determines a range to the object based on a characteristic of a Fourier transform the electrical output signal. A method is also provided for using the square wave digital chirp signal for optical chirp range detection.

Embodiments of the present disclosure include optical transmitters and transceivers with improved reliability. In some embodiments, the optical transmitters are used in network devices, such as in conjunction with a network switch. In one embodiment, lasers are operated at low power to improve reliability and power consumption. The output of the laser may be modulated by a non-direct modulator and received by integrated optical components, such as a modulator and/or multiplexer. The output of the optical components may be amplified by a semiconductor optical amplifier (SOA). Various advantageous configurations of lasers, optical components, and SOAs are disclosed. In some embodiments, SOAs are configured as part of a pluggable optical communication module, for example.

Methods and systems for redundant light sources by utilizing two inputs of an integrated modulator are disclosed and may include: an optoelectronic transmitter integrated in a semiconductor die with first and second laser sources coupled to the semiconductor die, said optoelectronic transmitter comprising an optical modulator with a first input waveguide coupled to the first laser source and second input waveguide coupled to the second laser source, the optoelectronic receiver being operable to: configure the first laser source to provide an optical signal to the first input of the optical modulator; and if the first laser source does not provide an optical signal, configure the second laser source to provide an optical signal to the second input of the optical modulator. The first laser source may be optically coupled to the first input waveguide and the second laser source optically coupled to the second input waveguide using grating couplers.

A cryogenic optoelectronic data link, comprising a sending module operating at a cryogenic temperature less than 100 K. An ultrasensitive electro-optic modulator, sensitive to input voltages of less than 10 mV, may include at least one optically active layer of graphene, which may be part of a microscale resonator, which in turn may be integrated with an optical waveguide or an optical fiber. The optoelectronic data link enables optical output of weak electrical signals from superconducting or other cryogenic electronic devices in either digital or analog form. The modulator may be integrated on the same chip as the cryogenic electrical devices. A plurality of cryogenic electrical devices may generate a plurality of electrical signals, each coupled to its own modulator. The plurality of modulators may be resonant at different frequencies, and coupled to a common optical output line to transmit a combined wavelength-division-multiplexed (WDM) optical signal.

A transmitter can include a laser operable to output an optical signal; a digital signal processor operable to receive user data and provide electrical signals based on the data; and a modulator operable to modulate the optical signal to provide optical subcarriers based on the electrical signals. A first one of the subcarriers carriers carries first TDMA encoded information and second TDMA encoded information, such that the first TDMA encoded information is indicative of a first portion of the data and is carried by the first one of the subcarriers during a first time slot, and the second TDMA encoded information is indicative of a second portion of the data and is carried by the first one of the subcarriers during a second time slot. The first TDMA encoded information is associated with a first node remote from the transmitter and the second TDMA encoded information is associated with a second node remote from the transmitter. A second one of the subcarriers carries third information that is not TDMA encoded, the third information being associated with a third node remote from the transmitter. A receiver and system also are described.

A wavelength division multiplexing filter comprises: a first multi-order Mach-Zehnder interferometer comprising a plurality of first-order Mach-Zehnder interferometers, and a second multi-order Mach-Zehnder interferometer comprising a plurality of first-order Mach-Zehnder interferometers; wherein the first multi-order Mach-Zehnder interferometer and the second multi-order Mach-Zehnder interferometer are included in a group of multiple multi-order Mach-Zehnder interferometers arranged within a binary tree arrangement, the binary tree arrangement comprising: a first set of a plurality of multi-order Mach-Zehnder interferometers, the first set including the first multi-order Mach-Zehnder interferometer, and having an associated spectral response with a first spacing between adjacent passbands, and a second set of at least twice as many multi-order Mach-Zehnder interferometers as in the first set, the second set including the second multi-order Mach-Zehnder interferometer, and having an associated spectral response with a second spacing between adjacent passbands that is twice the first spacing.

In a system for converting digital data into a modulated optical signal, an electrically controllable device, including a modulator having one or more actuating electrodes, provides an analog-modulated optical signal that is modulated in response to output data bits of a digital-to-digital mapping. A digital-to-digital conversion provides the mapping of input data words to the output data bits. The mapping enables adjustments to correct for non-linearities and other undesirable characteristics, thereby improving signal quality.

A light source unit (1000) of the present disclosure includes a light source part (100), a first electrical signal generating device (40-1) configured to control current that drives an optical semiconductor device (30), an optical modulator (200) having a Mach-Zehnder type optical waveguide (10) and an electrode configured to apply an electric field to the optical waveguide (10), and a second electrical signal generating device (40-2) configured to control a voltage that operates the optical modulator (200), the first electrical signal generating device (40-1) and the second electrical signal generating device (40-2) are synchronizably connected to each other, and intensity of light emitted from the optical modulator (200) is changed by the current controlled by the first electrical signal generating device (40-1) and the voltage controlled by the second electrical signal generating device (40-2).

Embodiments of the present disclosure include optical transmitters and transceivers with improved reliability. In some embodiments, the optical transmitters are used in network devices, such as in conjunction with a network switch. In one embodiment, lasers are operated at low power to improve reliability and power consumption. The output of the laser may be modulated by a non-direct modulator and received by integrated optical components, such as a modulator and/or multiplexer. The output of the optical components may be amplified by a semiconductor optical amplifier (SOA). Various advantageous configurations of lasers, optical components, and SOAs are disclosed. In some embodiments, SOAs are configured as part of a pluggable optical communication module, for example.