An electronic device may include a proximity sensor for detecting whether an external object is in the vicinity of the device. The proximity sensor may have a light detector and a light source that can be reused for data communications. The light detector may be coupled to optical receiver circuitry, whereas the light source may be coupled to optical transmitter circuitry. The optical transmitter circuitry may include encoding circuits configured to convert electrical signals to optical signals. The optical receiver circuitry may include decoding circuits configured to convert optical signals to electrical signals. The optical signals can be encoded and decoded using pulse width modulation schemes or amplitude modulation schemes.

An optical fiber holder is disclosed herein that includes at least one confinement slot for routing intermediate optical fibers within a housing of an optical assembly module, and preferably, a plurality of confinement slots for maintaining a target/nominal fiber bending radius for one or more intermediate optical fibers within the housing. Preferably, the optical fiber holder is disposed within the housing of an optical subassembly between an optical component, e.g., a TOSA arrangement and/or ROSA arrangement, and optical coupling receptacles, e.g., LC coupling receptacles, for optically coupling with external fibers for sending and/or receiving optical signals.

An optical fiber holder is disclosed herein that includes at least one confinement slot for routing intermediate optical fibers within a housing of an optical assembly module, and preferably, a plurality of confinement slots for maintaining a target/nominal fiber bending radius for one or more intermediate optical fibers within the housing. Preferably, the optical fiber holder is disposed within the housing of an optical subassembly between an optical component, e.g., a TOSA arrangement and/or ROSA arrangement, and optical coupling receptacles, e.g., LC coupling receptacles, for optically coupling with external fibers for sending and/or receiving optical signals.

Transmit-side equalization is disclosed for network devices and network communications methods employing onboard/co-packaged optics. An illustrative network device includes a substrate having a host device IC (integrated circuit) and an optical module IC connected by a short-reach link. The optical module IC having a transmit chain includes a CTLE (continuous time linear equalizer) to at least partly compensate for a channel response of the short-reach link, and a driver that amplifies an output of the CTLE for a photoemitter that couples to an optical fiber. The host device IC includes: a parallel-to-serial converter that produces a digital symbol stream; a digital to analog converter that supplies an analog signal to the short-reach link; and a pre-equalizer coupling the parallel-to-serial converter to the digital-to-analog converter, the pre-equalizer filtering the digital symbol stream to at least partly compensate for a channel response of a combined channel that includes the short-reach link, the CTLE, the driver, and the photoemitter.

Transmit-side equalization is disclosed for network devices and network communications methods employing onboard/co-packaged optics. An illustrative network device includes a substrate having a host device IC (integrated circuit) and an optical module IC connected by a short-reach link. The optical module IC having a transmit chain includes a CTLE (continuous time linear equalizer) to at least partly compensate for a channel response of the short-reach link, and a driver that amplifies an output of the CTLE for a photoemitter that couples to an optical fiber. The host device IC includes: a parallel-to-serial converter that produces a digital symbol stream; a digital to analog converter that supplies an analog signal to the short-reach link; and a pre-equalizer coupling the parallel-to-serial converter to the digital-to-analog converter, the pre-equalizer filtering the digital symbol stream to at least partly compensate for a channel response of a combined channel that includes the short-reach link, the CTLE, the driver, and the photoemitter.

A receiver circuit includes an input terminal for receiving an input current signal, a transimpedance amplifier having an input node, the transimpedance amplifier converting a current signal input to the input node into a voltage signal, an inductor having a first terminal and a second terminal, and a bypass circuit. The first terminal is coupled to the input terminal and the second terminal is coupled to the input node. The bypass circuit includes a bias circuit supplying a bias voltage, a first variable resistor coupled between the first terminal and the bias circuit, a second variable resistor coupled between the second terminal and the bias circuit, and an impedance adjustment circuit including a resistor and a capacitor connected in parallel to the resistor, the impedance adjustment circuit connected in series to at least one of the first variable resistor and the second variable resistor.

A receiver circuit includes an input terminal for receiving an input current signal, a transimpedance amplifier having an input node, the transimpedance amplifier converting a current signal input to the input node into a voltage signal, an inductor having a first terminal and a second terminal, and a bypass circuit. The first terminal is coupled to the input terminal and the second terminal is coupled to the input node. The bypass circuit includes a bias circuit supplying a bias voltage, a first variable resistor coupled between the first terminal and the bias circuit, a second variable resistor coupled between the second terminal and the bias circuit, and an impedance adjustment circuit including a resistor and a capacitor connected in parallel to the resistor, the impedance adjustment circuit connected in series to at least one of the first variable resistor and the second variable resistor.

The signal detection device includes the signal detection unit that derives the estimation vector of the transmission signal vector,

the first conversion unit that converts the estimation vector of the transmission signal vector to the estimation vector of the transmission signal vector based on the reduced basis, the first determination unit that converts the estimation vector of the transmission signal vector based on the reduced basis to the determination value vector of the transmission signal vector, the first update unit that updates the separation matrix, the second conversion unit that converts the first error signal vector to the second error signal vector based on the reduced basis, the second update unit that updates the error covariance matrix based on the reduced basis, the second determination unit that determines whether or not the predetermined condition is satisfied, and a third update unit that updates the unimodular matrix, the inverse matrix of the unimodular matrix, and the error covariance matrix based on the reduced basis when it is determined that the predetermined condition is established.

The signal detection device includes the signal detection unit that derives the estimation vector of the transmission signal vector,

the first conversion unit that converts the estimation vector of the transmission signal vector to the estimation vector of the transmission signal vector based on the reduced basis, the first determination unit that converts the estimation vector of the transmission signal vector based on the reduced basis to the determination value vector of the transmission signal vector, the first update unit that updates the separation matrix, the second conversion unit that converts the first error signal vector to the second error signal vector based on the reduced basis, the second update unit that updates the error covariance matrix based on the reduced basis, the second determination unit that determines whether or not the predetermined condition is satisfied, and a third update unit that updates the unimodular matrix, the inverse matrix of the unimodular matrix, and the error covariance matrix based on the reduced basis when it is determined that the predetermined condition is established.

An exemplary medical system includes a first electrical circuit (204-1) on a PCB (206), a second electrical circuit (204-2) on the PCB and electrically isolated from the first electrical circuit, and a free space optics interface assembly (302) on the PCB. The free space optics assembly includes a housing (402) defining a free space chamber (404) in the housing, an optical transmitter (416) having an input (426) that is electrically coupled to the first electrical circuit, and an optical receiver (418) in optical communication with the optical transmitter via the free space chamber and having an output (432) that is electrically coupled to the second electrical circuit. The optical transmitter and the optical receiver are hermetically sealed within the housing.