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.

Materials containing picocrystalline quantum dots that form artificial atoms are disclosed. The picocrystalline quantum dots (in the form of born icosahedra with a nearly-symmetrical nuclear configuration) can replace corner silicon atoms in a structure that demonstrates both short range and long-range order as determined by x-ray diffraction of actual samples. A novel class of boron-rich compositions that self-assemble from boron, silicon, hydrogen and, optionally, oxygen is also disclosed. The preferred stoichiometric range for the compositions is (B.sub.12H.sub.w).sub.xSi.sub.yO.sub.z with 3≤w≤5, 2≤x≤4, 2≤y≤5 and 0≤z≤3. By varying oxygen content and the presence or absence of a significant impurity such as gold, unique electrical devices can be constructed that improve upon and are compatible with current semiconductor technology.

An optical receiver that includes an input port configured to receive intensity modulated optical signal with multipath interference (MPI); a detector configured to convert the intensity modulated optical signal with multipath interference to an electrical signal; a high pass filter (HPF) configured to filter the electrical signal and suppress carrier-carrier beat noise induced by the MPI to produce a filtered electrical signal; and an output port configured to transmit the filtered electrical signal.

Embodiments may provide a way of communicating via an electromagnetic radiator, or light source, that can be amplitude modulated such as light emitting diode (LED) lighting and receivers or detectors that can determine data from light received from the amplitude modulated electromagnetic radiator. Some embodiments may provide a method of transmitting/encoding data via modulated LED lighting and other embodiments may provide receiving/decoding data from the modulated LED lighting by means of a device with a low sampling frequency such as a relatively inexpensive camera (as might be found in a smart phone). Some embodiments are intended for indoor navigation via photogrammetry (i.e., image processing) using self-identifying LED light anchors. In many embodiments, the data signal may be communicated via the light source at amplitude modulating frequencies such that the resulting flicker is not perceivable to the human eye.

Embodiments may provide a way of communicating via an electromagnetic radiator, or light source, that can be amplitude modulated such as light emitting diode (LED) lighting and receivers or detectors that can determine data from light received from the amplitude modulated electromagnetic radiator. Some embodiments may provide a method of transmitting/encoding data via modulated LED lighting and other embodiments may provide receiving/decoding data from the modulated LED lighting by means of a device with a low sampling frequency such as a relatively inexpensive camera (as might be found in a smart phone). Some embodiments are intended for indoor navigation via photogrammetry (i.e., image processing) using self-identifying LED light anchors. In many embodiments, the data signal may be communicated via the light source at amplitude modulating frequencies such that the resulting flicker is not perceivable to the human eye.

An optical transmitter includes: a controller that generates a multi-level amplitude modulated signal based on transmission data that is binary data; a driver that generates a drive signal in accordance with the multi-level amplitude modulated signal; and a light emitter that generates an optical signal in accordance with the drive signal. The controller selects one of a first encoding method and a second encoding method in accordance with a switching signal. The controller generates the multi-level amplitude modulated signal by converting a bit string of M (M is an integer of 2 or more) bits included in the transmission data into a pulse signal having 2.sup.M logic levels using a selected encoding method. The controller sets voltage values of the 2.sup.M logic levels depending on the selected encoding method.

Optical transmitter includes: signal processing circuit, optical modulator, optical filter, and delay circuit. The signal processing circuit generates N drive signals for generating a modulated optical signal. Symbol rate of the modulated optical signal is fs and each symbol of the modulated optical signal transmits N bits. The optical modulator includes Mach-Zehnder interferometer and N phase-shift segments each of which shifts a phase of light propagating through an optical path of the Mach-Zehnder interferometer according to the N drive signals. The optical filter removes, from output light of the optical modulator, a frequency component in a range of ±fs/2 with respect to a center frequency of the modulated optical signal, and extracts at least a part of other frequency components. The delay circuit controls timings of the N drive signals so as to reduce optical power of the frequency component extracted by the optical filter.

A packaged integrated white light source configured for illumination and communication or sensing comprises one or more laser diode devices. An output facet configured on the laser diode device outputs a laser beam of first electromagnetic radiation with a first peak wavelength. The first wavelength from the laser diode provides at least a first carrier channel for a data or sensing signal.

A method (100) of encoding communications traffic bits onto an optical carrier signal in a pulse amplitude modulation, PAM, format. The method comprises: receiving (102) bits to be transmitted; receiving (104) an optical carrier signal comprising optical pulses having an amplitude and respective phases; performing (106) PAM of the optical pulses to encode at least one respective bit in one of a pre-set plurality of amplitudes of a said optical pulse; and performing (108) phase modulation of the optical pulses to encode at least one further respective bit in a phase difference between a said optical pulse and a consecutive optical pulse.

A method (100) of encoding communications traffic bits onto an optical carrier signal in a pulse amplitude modulation, PAM, format. The method comprises: receiving (102) bits to be transmitted; receiving (104) an optical carrier signal comprising optical pulses having an amplitude and respective phases; performing (106) PAM of the optical pulses to encode at least one respective bit in one of a pre-set plurality of amplitudes of a said optical pulse; and performing (108) phase modulation of the optical pulses to encode at least one further respective bit in a phase difference between a said optical pulse and a consecutive optical pulse.