| 摘要 |
PROBLEM TO BE SOLVED: To feed light to a PD provided for each wavelength while maintaining sufficient light intensity for high-speed communication.SOLUTION: An optical element includes first to Nth photosensitive elements 4-4for receiving first to N-th light components λ-λof different wavelengths contained in an incoming first optical signal IN, a grating 3G for outputting a second optical signal OUT along a same light path as that of the first optical signal, and a wavelength filter block 6 with a reflective member 11 provided above the grating, all provided on a common substrate 1. The wavelength filter block has a wavelength filter film 7 having zeroth to N-th regions for transmitting the second optical signal and the first to N-th light components, respectively, where the second optical signal transmits through the zeroth region, and the first to N-th light components reflected by the zeroth region propagates through while being reflected between the reflective member and the first to N-th regions, during which the i-th light component transmits through the i-th region (i is an integer from 1 to N) and is received by the i-th photosensitive element 4. |
