Holevo capacity achieving joint detection receiver

An optical receiver of comprising:

• a unitary transformation operator to:
• receive an n-symbol optical codeword associated with a codebook, and
• perform, based on the codebook, a unitary transformation on the n-symbol optical codeword to generate a transformed optical codeword;
• the unitary transformation operator including a combined unitary transformation operator that performs a particular unitary transformation on the n-symbol optical codeword followed by a plurality of single mode unitary transformations on particular optical symbols of the transformed optical codeword;
• n optical detectors, a particular one of the n optical detectors being to:
• detect a particular optical symbol of the transformed optical codeword, and
• determine whether the particular optical symbol corresponds to at least a first optical symbol or a second optical symbol;
• and
• a decoder to:
• construct a codeword based on whether the particular optical symbol corresponds to the at least the first optical symbol or the second optical symbol, and
• decode the constructed codeword into a message using the codebook.

An optical receiver comprising:

• a unitary transformation operator to:
• receive an n-symbol codeword associated with a codebook,
• where the n-symbol optical codeword corresponds to a temporally encoded codeword, and
• perform, based on the codebook, a unitary transformation on the temporally encoded codeword to generate a transformed optical codeword;
• n optical detectors, a particular one of the n optical detectors being to:
• detect a particular optical symbol of the transformed optical codeword, and
• determine whether the particular optical symbol of the transformed optical codeword corresponds to at least a first optical symbol or a second optical symbol;
• an optical demultiplexer to select a particular optical symbol of the temporally encoded codeword;
• n optical buffers,
• a particular one of the n optical buffers being to receive the particular optical symbol of the temporally encoded codeword, and
• the n optical buffers being to forward all optical symbols of the temporally encoded codeword to the unitary transformation operator substantially at a same time;
• and
• a decoder to:
• construct a codeword based on determining whether the particular optical symbol of the transformed optical codeword corresponds to the at least the first optical symbol or the second optical symbol, and
• decode the constructed codeword into a message using the codebook.

An optical receiver comprising:

• a unitary transformation operator to:
• receive an n-symbol codeword associated with a codebook,
• the n-symbol codeword being encoded based on a first order Reed-Muller code,
• the unitary transformation operator including n*log2(n/2) beam splitters, and
• perform, based on the codebook, a unitary transformation on the encoded n-symbol codeword to generate a transformed optical codeword;
• n optical detectors,
• the n optical detectors including n single photon detectors,
• a particular one of the n optical detectors being to:
• detect a particular optical symbol of the transformed optical codeword, and
• determine whether the particular optical symbol corresponds to at least a first optical symbol or a second optical symbol;
• a Dolinar receiver,
• a first one of the n single photon detectors detecting a photon prior to other ones of the n single photon detectors, triggering the Dolinar receiver;
• and
• a decoder to:
• construct a codeword based on determining whether the particular optical symbol corresponds to the at least the first optical symbol or the second optical symbol, and
• decode the constructed codeword into a message using the codebook.

A method performed by an optical receiver, the method comprising:

• receiving, by the optical receiver, an optical codeword associated with a codebook,
• the optical codeword comprising n symbols, and
• the optical codeword being based on a Hadamard matrix;
• performing, by the optical receiver, a unitary transformation on the received optical codeword to generate a transformed optical codeword comprising n transformed symbols,
• where the unitary transformation corresponds to a lossless transformation on a quantum state of the n symbols, and
• the unitary transformation including n*log2(n/2) beam splitting operations;
• determining, by n single photon detectors included in the optical receiver and for the n transformed symbols, whether a particular one of the n transformed symbols corresponds to at least a first optical symbol or a second optical symbol;
• and
• generating, by the optical receiver, an electrical codeword, corresponding to the optical codeword, based on determining whether the particular one of the n transformed symbols corresponds to the at least the first optical symbol or the second optical symbol.

A method comprising:

• receiving, by an optical receiver, an optical codeword associated with a codebook,
• the optical codeword comprising n symbols;
• performing, by the optical receiver, a unitary transformation on the received optical codeword to generate a transformed optical codeword comprising n transformed symbols,
• the unitary transformation corresponding to a lossless transformation on a quantum state of the n symbols, and
• performing the unitary transformation on the received optical codeword including:
• performing a unitary transformation on the received optical codeword;
• and
• performing a plurality of single mode unitary transformations on particular optical symbols of the transformed optical codeword;
• determining, by the optical receiver and for the n transformed symbols, whether a particular one of the n transformed symbols corresponds to at least a first optical symbol or a second optical symbol;
• and
• generating, by the optical receiver, an electrical codeword, corresponding to the optical codeword, based on determining whether the particular one of the n transformed symbols corresponds to the at least the first optical symbol or the second optical symbol.

A method comprising:

• receiving, by an optical receiver, an optical codeword associated with a codebook,
• the optical codeword being encoded based on a first order Reed-Muller code, and
• the optical codeword comprising n symbols;
• performing, by the optical receiver, a unitary transformation on the received optical codeword to generate a transformed optical codeword comprising n transformed symbols,
• the unitary transformation corresponding to a lossless transformation on a quantum state of the n symbols, and
• the unitary transformation including n*log2(n/2) beam splitting operations, and
• determining, for the n transformed symbols, whether a particular one of the n transformed symbols corresponds to at least a first optical symbol or a second optical symbol,
• determining whether the particular one of the n transformed symbols corresponds to a first optical symbol or a second optical symbol is performed by n single photon detectors in combination with a Dolinar receiver or a Kennedy receiver triggered by a first one of the n single photon detectors that detects a photon;
• and
• generating, by the optical receiver, an electrical codeword, corresponding to the optical codeword, based on the determination.