| 摘要 |
PROBLEM TO BE SOLVED: To facilitate setting of the set value of a modulation current in an optical transceiver performing differential driving of an LD.SOLUTION: In the control method of an LD, a bias current is defined by an APC circuit 5, a modulation current giving a predetermined extinction ratio is defined by a primary expression; I=α×I+&bgr;...(1), [Iis a set value of a bias current, α, &bgr; are coefficients], and the coefficients α, &bgr; are set by following formula; α=c×M/a...(2), &bgr;=I-α×I...(3), a=(M-M)×(c×I-I)/(I-I)...(4), M=2×(ER-1)/(ER+1)...(5)[Iis a set value of a bias current giving a specified average optical output under normal temperature, ERis an extinction ratio (N=1,2) when the modulation current is driven with a set value I, Iis a threshold current value of LD under normal temperature, and c is a constant]. |
