An integrated optical circulator enabling polarization diversity, the integrated optical circulator comprising: a first port configured to receive a first optical signal; a second port configured to transmit the first optical signal received at the first port and also configured to receive a second optical signal; a first polarization beam splitter; a first reflective surface optically coupled with the first polarization beam splitter; a second polarization beam splitter; a first optical polarization rotator, a second optical polarization rotator and a third optical polarization rotator; wherein the first polarization beam splitter is configured to: receive the second optical signal; split the second optical signal into a first optical signal component and a second optical signal component; direct the first optical signal component towards the first reflective surface so that it is not received by the second polarization splitter, wherein the first reflective surface is configured to further direct the first optical signal component to pass through the first optical polarization rotator; and direct the second optical signal component through the second optical polarization rotator; wherein the second polarization beam splitter is configured to receive the second optical signal component after the second optical signal component passes through the second optical polarization rotator, and direct the second optical signal component towards a second reflective surface, the second reflective surface directing the second optical signal component towards the third optical polarization rotator; a third port configured to transmit the first optical signal component of the second optical signal after it passes through the first optical polarization rotator, the third port transmitting the first optical signal component at a first polarization state; characterised by a fourth port configured to transmit the second optical signal component of the second optical signal after it passes through the third optical polarization rotator, the fourth port transmitting the second optical signal component at a second polarization state substantially aligned with the first polarization state. a first port configured to receive a first optical signal; a second port configured to transmit the first optical signal received at the first port and also configured to receive a second optical signal; a first polarization beam splitter; a first reflective surface optically coupled with the first polarization beam splitter; a second polarization beam splitter; a first optical polarization rotator, a second optical polarization rotator and a third optical polarization rotator; wherein the first polarization beam splitter is configured to: receive the second optical signal; split the second optical signal into a first optical signal component and a second optical signal component; direct the first optical signal component towards the first reflective surface so that it is not received by the second polarization splitter, wherein the first reflective surface is configured to further direct the first optical signal component to pass through the first optical polarization rotator; and direct the second optical signal component through the second optical polarization rotator; receive the second optical signal; split the second optical signal into a first optical signal component and a second optical signal component; direct the first optical signal component towards the first reflective surface so that it is not received by the second polarization splitter, wherein the first reflective surface is configured to further direct the first optical signal component to pass through the first optical polarization rotator; and direct the second optical signal component through the second optical polarization rotator; wherein the second polarization beam splitter is configured to receive the second optical signal component after the second optical signal component passes through the second optical polarization rotator, and direct the second optical signal component towards a second reflective surface, the second reflective surface directing the second optical signal component towards the third optical polarization rotator; a third port configured to transmit the first optical signal component of the second optical signal after it passes through the first optical polarization rotator, the third port transmitting the first optical signal component at a first polarization state; characterised by a fourth port configured to transmit the second optical signal component of the second optical signal after it passes through the third optical polarization rotator, the fourth port transmitting the second optical signal component at a second polarization state substantially aligned with the first polarization state.