An optical module of the present invention includes a first substrate 1,
a second substrate 2, a PD 3, a LD 4, and an optical fiber
5. The first substrate 1 has a first optical waveguide core 1c
formed therein. The second substrate 2 has a second optical waveguide
core 2c formed therein. The first optical waveguide core 1c
and the second optical waveguide core 2c form an optical connecting
portion where the first substrate 1 and the second substrate 2 are
bonded to each other. The LD 4 is capable of transmitting an optical signal
via the second optical waveguide core 2c and the optical fiber 5.
The PD 3 is capable of receiving an optical signal which enters the second
optical waveguide core 2c from the optical fiber 5, and propagates
through the first optical waveguide core 1c via the optical connecting
portion formed between the first optical waveguide core 1c and the
second optical waveguide core 2c.
