Methods and systems for a free space CWDM MUX/DEMUX for integration with a grating coupler based silicon platform may include an optical assembly coupled to a photonic chip. The optical assembly includes a lens array on the top surface of the chip, an angled mirror, a transparent spacer, and a plurality of thin film filters. The optical assembly may receive an input optical signal comprising a plurality of optical signals at different wavelengths via an optical fiber coupled to the optical assembly, communicate the plurality of optical signals through the transparent spacer, pass a first of the plurality of optical signals through a corresponding one of the plurality of thin film filters while reflecting others of the plurality of optical signals back into the transparent spacer, and reflect the others of the plurality of signals towards a second of the plurality of thin film filters.

Disclosed herein is a wavelength-division multiplexing device with a unified passband. In particular, disclosed is a wavelength-division multiplexing (WDM) device with at least a common port, a channel port, and a WDM filter. The common port is configured for optical communication of a multiplexed signal to the WDM filter. A demultiplexed signal of the multiplexed signal includes a first secondary demultiplexed signal within a first wavelength range and a second secondary demultiplexed signal within a second wavelength range, which are separated from each other by a third wavelength range. The first WDM filter has a single unified passband including the first wavelength range, the second wavelength range, and the third wavelength range, such that the first WDM filter is configured to pass the first secondary demultiplexed signal and the second secondary demultiplexed signal to the first channel port.

Aspects described herein include an optical apparatus comprising at least a first Bragg grating of a first stage. The first Bragg grating is configured to transmit a first two wavelengths and to reflect a second two wavelengths of a received optical signal. The optical apparatus further comprises a second Bragg grating of a second stage. The second Bragg grating is configured to transmit one of the first two wavelengths and to reflect the other of the first two wavelengths. The optical apparatus further comprises a third Bragg grating of the second stage. The third Bragg grating is configured to transmit one of the second two wavelengths and to reflect the other of the second two wavelengths.

Aspects described herein include an optical apparatus comprising at least a first Bragg grating of a first stage. The first Bragg grating is configured to transmit a first two wavelengths and to reflect a second two wavelengths of a received optical signal. The optical apparatus further comprises a second Bragg grating of a second stage. The second Bragg grating is configured to transmit one of the first two wavelengths and to reflect the other of the first two wavelengths. The optical apparatus further comprises a third Bragg grating of the second stage. The third Bragg grating is configured to transmit one of the second two wavelengths and to reflect the other of the second two wavelengths.

Exemplary multi-channel optical couplers include a molded coupling module comprising a first surface, a second surface, a lens array receptacle, and fiber receptacles for optical fibers; an optical arrangement comprising: a particular surface carrying a reflective coating, and a further surface carrying a plurality of optical filters, each configured to pass a single optical wavelength; a first lens array configured such that each lens is optically aligned with the plurality of optical filters via at least the reflective coating, and with a position, within a particular fiber receptacle, corresponding to the end of a particular optical fiber; a second lens array arranged with the second surface such that each lens is optically aligned with an optical filter. The optical block and lens arrays can be configured such that the optical coupler produces no more than 10 dB of crosstalk on any of the optical wavelengths passed by the optical filters.

In one embodiment, a first group of splitters receives a group of signals from a group of transmitters. Each splitter in the first group of splitters splits a signal into a plurality of signals that are sent to a plurality of multiplexers. A multiplexer in the plurality of multiplexers receives one of the plurality of signals from each splitter in the group of splitters and multiplexes the received one of the plurality of signals into a multiplexed signal. The multiplexer sends the multiplexed signal through a single connection in which upstream signals are sent to a group of nodes and downstream signals are received from the group of nodes. A de-multiplexer de-multiplexes the multiplexed signal into the group of signals and sends the group of signals to the group of nodes via a second group of splitters that are connected to the group of nodes.

A redundancy system for a distributed antenna system is provided. The system includes a first communication link, a second communication link, a first communication node and a second communication node. The first communication link traverses first path. The second communication link traverses a second path. The second path is spatially separated from the first path. The first communication node is communicatively coupled to transmit the same signal through both the first communication link and the second communication link. The second communication node has a receiver system that is communicatively coupled to receive the signals transmitted through the first and second communication links. The receiver system is configured to synchronize delay and phase differences between the received signals and then combine the signals together to generate a single output.

The invention relates to optical communication methods and systems. In particular, the invention relates to an optical communication method and system which is configured to create a multiplexed beam from an incident beam, wherein the multiplexed beam comprises a predetermined number of spatial modes simultaneously generated and multiplexed together in a fashion that is independent of wavelength. The spatial modes have two degrees of spatial freedom. The multiplexed beam is de-multiplexed downstream from multiplexing thereof in the communication system in a simultaneous fashion independent of wavelength to yield the predetermined number of spatial mode. The modes are used in optical communication as channels or as bits in a bit (de) encoding scheme.

An optical network is provided that includes at least one strand of a plurality of strands of optical fiber optically connected to a first fiber distribution hub and an access terminal. The at least one strand optically is also connected to a second fiber distribution hub and the access terminal. The at least one strand thus provides a full duplex optical path in a first direction from the first fiber distribution hub to the access terminal and in a second direction from the second fiber distribution hub to the access terminal.

A method for configuring hardware-configured optical links includes generating a first optical signal comprising a slow scan of wavelength channels where the slow scan has a dwell time on a particular wavelength channel. A second optical signal is generated comprising a fast scan of wavelength channels, where the fast scan has a dwell time on a particular wavelength channel and a complete channel scan time where the slow scan dwell time is greater than or equal to complete channel scan time. The first optical signal is transmitted over a link and a portion is then detected. A pulse of light having a duration that is less than the dwell time on the particular wavelength channel of the fast scan is then detected. Client data traffic is then sent over the link in response to the detected pulse of light and the detected portion of the first optical signal.