An integrated optical module, comprising:
- a first light-emitting-element pair which is formed of a first mounting section having a first light-emitting element for emitting from a first light-emitting spot thereof, a first optical signal, and a second mounting section arranged alongside the first mounting section and having a second light-emitting element for emitting from a second light-emitting spot thereof, a second optical signal whose wavelength is different from that of the first optical signal;
- a second light-emitting-element pair which is formed of a third mounting section having a third light-emitting element for emitting from a third light-emitting spot thereof, a third optical signal whose wavelength is different to those of the first and second optical signals,
- and a fourth mounting section arranged alongside the third mounting section and having a fourth light-emitting element for emitting from a fourth light-emitting spot thereof, a fourth optical signal whose wavelength is different from those of the first to third optical signals;
- a first collimating lens for transforming the first optical signal emitted from the first light-emitting spot, into parallel light;
- a second collimating lens for transforming the second optical signal emitted from the second light-emitting spot, into parallel light;
- a third collimating lens for transforming the third optical signal emitted from the third light-emitting spot, into parallel light;
- a fourth collimating lens for transforming the fourth optical signal emitted from the fourth light-emitting spot, into parallel light;
- an optical multiplex section having a first filter for transmitting therethrough only the wavelength of the first optical signal transformed into parallel light by the first collimating lens;
- a front-side mirror for reflecting the first optical signal transmitted through the first filter;
- a second filter arranged alongside the first filter, for transmitting therethrough only the wavelength of the second optical signal transformed into parallel light by the second collimating lens, and for reflecting the first optical signal reflected by the front-side mirror and multiplexing it with the transmitted second optical signal;
- a back-side mirror for reflecting again the first and second optical signals reflected by the front-side mirror, toward the front-side mirror;
- a third filter for transmitting therethrough only the wavelength of the third optical signal transformed into parallel light by the third collimating lens;
- and a fourth filter arranged alongside the third filter, for transmitting therethrough only the wavelength of the fourth optical signal transformed into parallel light by the fourth collimating lens, and for reflecting the third optical signal reflected by the front-side mirror and multiplexing it with the transmitted fourth optical signal;
- wherein, assuming that a distance between the first light-emitting spot in the first mounting section and the second light-emitting spot in the second mounting section and a distance between the third light-emitting spot in the third mounting section and the fourth light-emitting spot in the fourth mounting section, are each d, a distance between the second light-emitting spot in the second mounting section and the third light-emitting spot in the third mounting section is nd (n denotes an integer of 2 or more);
- wherein the first light-emitting element is mounted in the first mounting section so as to be displaced from its center in a width direction across an emission direction of the first optical signal, toward the second light-emitting element;
- and the second light-emitting element is mounted in the second mounting section so as to be displaced from its center in a width direction across an emission direction of the second optical signal, toward the first light-emitting element;
- and
- wherein the third light-emitting element is mounted in the third mounting section so as to be displaced from its center in a width direction across an emission direction of the third optical signal, toward the fourth light-emitting element;
- and the fourth light-emitting element is mounted in the fourth mounting section so as to be displaced from its center in a width direction across an emission direction of the fourth optical signal, toward the third light-emitting element.