Multimode optical fiber couplers are widely used in optical local networks or FTTx networks that use multimode fibers. These couplers can be fabricated using 50/125 or 62.5/125 micron fibers and at central wavelengths of 850nm or 1310n. Single mode wideband couplers have 80nm bandwidth, compared to 40nm of standard single mode couplers. This product has very low excess loss and high temperature stability.