Optical transmission systems and optical receivers and receiving methods for use therein

A method of tuning an optical filter to an optical signal wavelength comprising:

• providing an optical filter having a filter bandwidth including an optical signal wavelength and a portion of a tuning wavelength;
• transmitting information via the optical signal wavelength and along with the tuning wavelength to said filter;
• receiving a first portion of the tuning wavelength stopped by the filter and a second portion of the tuning wavelength passed by the filter;
• and,
• tuning the filter based on the relative amount of the first and second received portions.

An optical receiver comprising:

• an optical filter having a filter bandwidth including at least one signal wavelength and a portion of a tuning wavelength;
• an optical to electrical signal converter configured to receive at least one signal wavelength from said filter;
• a first tuning optical to electrical converter configured to receive one of a first portion of the tuning wavelength stopped by said filter and a second portion of the tuning wavelength passed by said filter;
• and
• a controller configured to tune the filter bandwidth based on the portion of the tuning wavelength received by said first tuning converter.

An optical transmission system comprising:

• at least one optical transmitter configured to transmit at least one signal wavelength and a tuning wavelength;
• an optical receiver including an optical filter having a filter bandwidth including the at least one signal wavelength and a percentage of the tuning wavelength and an optical to electrical signal converter configured to receive the at least one signal wavelength from said filter;
• a tuning optical to electrical converter configured to receive a first portion of the tuning wavelength from said filter;
• and,
• a filter controller configured to tune the filter bandwidth based on the first portion of the tuning wavelength power and a tuning wavelength set point power.

A method of transmitting and receiving information, comprising:

• transmitting the information via an optical signal wavelength;
• transmitting a tuning signal via a tuning wavelength;
• filtering the information and the tuning signal with an optical filter;
• converting a portion of the tuning signal into an electrical tuning signal;
• tuning the optical filter in response to the electrical tuning signal;
• and
• converting the information into an electrical information signal.

A method of receiving information transmitted via an optical signal wavelength and transmitted with a tuning signal at a tuning wavelength, comprising:

• filtering the information at the optical signal wavelength and a portion of the tuning signal at the tuning wavelength with an optical filter;
• converting the portion of the tuning signal into an electrical tuning signal;
• tuning the optical filter in response to the electrical tuning signal;
• and
• converting the information into an electrical information signal.

An optical receiver comprising:

• an optical filter having a filter bandwidth selective to an information signal wavelength, selective to a first portion of a tuning wavelength, and not selective to a second portion of the tuning wavelength;
• an optical to electrical information signal converter having an optical input terminal configured to receive the information signal wavelength from the filter and having an electrical output terminal;
• an optical to electrical tuning signal converter having an optical input terminal configured to receive one of the first and second portions of the tuning wavelength, and having an electrical output terminal;
• and
• a filter controller having an input terminal and configured to adjust the filter;
• and
• a controller having an input terminal connected to the output terminal of the tuning converter, and having an output terminal connected to the input terminal of the filter controller, and wherein the controller includes computer readable instructions which, when executed by the controller, cause the controller to perform the steps of:
• reading a signal at the input terminal of the controller;
• comparing the signal with a predetermined condition;
• and
• sending a control signal to the filter controller depending on a relationship between the signal and the predetermined condition.