Optical transceiver control method and optical transceiver

1 . A control method of an optical transceiver having a transmission port, a reception port, and a light source for transmission and reception of an optical signal, the control method comprising:

determining whether a state of a connection of a transmission path to the reception port is a loopback connection from the transmission port; and

switching a control of a gain of the reception from an automatic gain control (AGC) to a fixed gain when determining the state of the connection to be the loopback connection.

2 . The control method according to claim 1 , wherein the determining includes determining whether the state of the connection is the loopback connection, based on a change of a frequency offset amount between a locally generated light and the optical signal with respect to a change of a frequency of the light source.

3 . The control method according to claim 1 , wherein the determining includes determining the state of the connection to be the loopback connection, when a frequency of the light source is changed by a predetermined amount and a change of the predetermined amount is detected in a frequency of the optical signal at a receiving-side.

4 . The control method according to claim 3 , wherein

the determining includes:

executing, a plurality of times, a process of changing the frequency of the light source by the predetermined amount and detecting the frequency of the optical signal at the receiving-side, and

determining the state of the connection to be the loopback connection, when a frequency offset amount between the locally generated light and the optical signal detected at the receiving-side is within a predetermined threshold range for all the plurality of times the process is performed.

5 . The control method according to claim 3 , wherein the determining includes determining the state of the connection of the transmission path to be a peer-to-peer connection, when a frequency offset amount between the locally generated light and the optical signal detected at the receiving-side is outside a predetermined threshold range when the frequency of the light source is changed by the predetermined amount.

6 . The control method according to claim 1 , wherein

the determining includes:

inserting an identification (ID) unique to the optical transceiver into an available region of the optical signal to be transmitted from the transmission port, and

determining the state of the connection to be the loopback connection, when an inclusion of the ID of the optical transceiver in the optical signal received via the reception port is detected.

7 . The control method according to claim 1 , further comprising after the switching:

determining whether an error has occurred in reception data processed for reception; and

re-executing the determining the state of the connection, when determining that the error has occurred.

8 . The control method according to claim 1 , further comprising outputting, to an external device, a result of the determining the state of the connection.

9 . The control method according to claim 1 , wherein the light source is a single light source for the transmission and the reception.

10 . The control method according to claim 1 , wherein

the light source includes a first light source for the transmission and a second light source for the reception, and

the determining includes determining whether the state of the connection is the loopback connection, based on a first reception data of an instance when a frequency of the second light source is not changed and a second reception data of an instance when the frequency of the second light source is changed by a predetermined amount.

11 . The control method according to claim 10 , wherein the determining includes determining whether the state of the connection is the loopback connection, according to a combination of whether a signal bandwidth of the second reception data matches a signal bandwidth of the first reception data and whether a signal bandwidth of a third data matches the signal bandwidth of the first reception data, based on the first reception data, the second reception data, and the third data obtained by calculating and restoring the predetermined amount changed in the second reception data.

12 . The control method according to claim 1 , wherein

the light source includes a first light source for the transmission and a second light source for the reception, and

the determining includes determining whether the state of the connection is the loopback connection, according to a combination of whether a signal bandwidth of a second reception data matches a signal bandwidth of a first reception data and whether a signal bandwidth of a third data matches the signal bandwidth of the first reception data, based on the first reception data of an instance when a frequency of the second light source is changed a predetermined amount in a first direction, the second reception data of an instance when the frequency of the second light source is changed the predetermined amount in a second direction different from the first direction, and the third data obtained by calculating and restoring an absolute value of a sum of the predetermined amount changed in the first direction and the predetermined amount changed in the second direction in the second reception data.

13 . An optical transceiver having a transmission port, a reception port, and a light source for transmission and reception of an optical signal, the optical transceiver comprising a processor configured to:

determine whether a state of a connection of a transmission path to the reception port is a loopback connection from the transmission port; and

switch a control of a gain of the reception from an automatic gain control (AGC) to a fixed gain when determining the state of the connection to be the loopback connection.