Optical module

An optical module comprising:

• a semiconductor laser;
• an optical monitor including a first optical receiver to receive a laser beam from the semiconductor laser, an optical filter to receive the laser beam from the semiconductor laser, and a second optical receiver to receive the laser beam via the optical filter;
• a stem on which a temperature adjuster is mounted, the temperature adjuster is configured to adjust a temperature in the semiconductor laser and a temperature in the optical monitor, and to perform control, when a wavelength monitor value Iλ/Ip, which is a ratio between an optical power monitor value Ip obtained by an output from the first optical receiver and a wavelength monitor value Iλ obtained by an output from the second optical receiver, deviates from a wavelength set value, to change a temperature to be given to the semiconductor laser and the optical monitor;
• a base that is mounted and fixed on a mounting surface of the temperature adjuster mounted on the stem and includes an elevation surface portion on which the semiconductor laser is mounted and fixed, and a flat surface portion that is formed integrally with the elevation surface portion and on which the optical monitor is mounted and fixed at a position where a backward laser beam of the semiconductor laser is received;
• and
• a cylindrical cap having a bottomed portion and a side wall portion, the bottomed portion having a window through which a forward laser beam of the semiconductor laser is emitted, the cap covering an inner flat surface side of the stem, and having an open end surface of the side wall portion fixed in contact with a peripheral end portion of the inner flat surface of the stem.