Optical demodulator

An optical demodulation method, comprising:

• splitting, by an optical splitter, input light for a first time, wherein a first path of light and a second path of light obtained through the splitting for the first time are emitted to a first reflective mirror and a second reflective mirror respectively;
• reflecting, by the first reflective mirror, the first path of light to the optical splitter, and reflecting, by the second reflective mirror, the second path of light to the optical splitter;
• splitting, by the optical splitter for a second time, the first path of light reflected back by the first reflective mirror, wherein two paths of light obtained by splitting the first path of light are emitted to the first reflective mirror and a third reflective mirror respectively, and splitting for the second time the second path of light reflected back by the second reflective mirror, wherein two paths of light obtained by splitting the second path of light are emitted to the first reflective mirror and the third reflective mirror respectively;
• reflecting, by the first reflective mirror, one of the two paths of light that are split from the first path of light and the second path of light to the optical splitter, and reflecting, by the third reflective mirror, the other of the two paths of light that are split from the first path of light and the second path of light to the optical splitter;
• and splitting, by the optical splitter, two paths of light that are reflected back by the first reflective mirror and the third reflective mirror respectively and obtained by splitting the first path of light, and then making the split light to interfere with each other, so as to obtain and emit two paths of light with different phases, and splitting two paths of light reflected back by the first reflective mirror and the third reflective mirror respectively and obtained by splitting the second path of light, and then making the split light to interfere with each other, so as to obtain and emit two paths of light with different phases, wherein, the first, second and third reflective mirrors are separated from the optical splitter, and positions of reflections of the first path of light and the second path of light reflected back by the first reflective mirror and the second reflective mirror respectively are adjustable with respect to each other on the optical splitter, by adjustment of an incident angle of the input light, a distance between the first reflective mirror and the optical splitter, and a distance between the second reflective mirror and the optical splitter.

A communication device, comprising an optical receiver and a optical demodulator, wherein:

• the optical demodulator, comprises a first reflective mirror, a second reflective mirror, a third reflective mirror, and an optical splitter, wherein the first reflective mirror is located at one side of the optical splitter, and the second reflective mirror and the third reflective mirror are located at the other side of the optical splitter, and the first, second and third reflective mirrors are separated from the optical splitter;
• the optical splitter is configured to:
• split input light for a first time, wherein a first path of light and a second path of light obtained through the splitting for the first time are emitted to the first reflective mirror and the second reflective mirror respectively;
• split for a second time the first path of light reflected back by the first reflective mirror, wherein two paths of light obtained by splitting the first path of light are emitted to the first reflective mirror and the third reflective mirror respectively, and split for the second time the second path of light reflected back by the second reflective mirror, wherein two paths of light obtained by splitting the second path of light are emitted to the first reflective mirror and the third reflective mirror respectively;
• and split two paths of light that are reflected back by the first reflective mirror and the third reflective mirror respectively and obtained by splitting the first path of light, and then make the split light to interfere with each other, so as to obtain and emit two paths of light with different phases, and split two paths of light that are reflected back by the first reflective mirror and the third reflective mirror respectively and obtained by splitting the second path of light, and then make the split light to interfere with each other, so as to obtain and emit two paths of light with different phases;
• the first reflective mirror is configured to:
• reflect the first path of light to the optical splitter after the splitting for the first time;
• reflect one of the two paths of light split from the first path of light to the optical splitter after the splitting for the second time, so that the optical splitter splits the two paths of light obtained by splitting the first path of light, and then makes the split light to interfere with each other, so as to obtain two paths of light with different phases;
• and reflect one of the two paths of light split from the second path of light to the optical splitter, so that the optical splitter splits the two paths of light obtained by splitting the second path of light, and then makes the split light to interfere with each other, so as to obtain two paths of light with different phases;
• the second reflective mirror is configured to reflect the second path of light to the optical splitter after the splitting for the first time;
• the third reflective mirror is configured to:
• reflect the other of the two paths of light split from the first path of light to the optical splitter after the splitting for the second time, so that the optical splitter splits the two paths of light obtained by splitting the first path of light, and then makes the split light to interfere with each other, so as to obtain two paths of light with different phases;
• and reflect the other of the two paths of light split from the second path of light to the optical splitter, so that the optical splitter splits the two paths of light obtained by splitting the second path of light, and then makes the split light to interfere with each other, so as to obtain two paths of light with different phases;
• and
• the optical receiver is configured to convert an optical signal demodulated by the optical demodulator into an electrical signal,
• wherein positions of reflections of the first path of light and the second path of light reflected back by the first reflective mirror and the second reflective mirror respectively are adjustable with respect to each other on the optical splitter, by adjustability of an incident angle of the input light, a distance between the first reflective mirror and the optical splitter, and a distance between the second reflective mirror and the optical splitter.